JP3777878B2 - Method for producing metal matrix composite material - Google Patents

Description

図１に、上記の各反応をＤＴＡ（differential thermal analysis:示差熱分析）で観測した一例を示す。同図は、各反応を明確に分離して検出できるように、５℃／min 程度の遅い昇温速度で観測した結果である。
【００２３】
図中の左寄り（低温寄り）に、上向きの大きな２つの発熱ピークと、その間に挟まれて下向きの大きな一つの吸熱ピークが生じている。これらのピークは、低温側から順に、(1) 固体Ｔｉと固体Ａｌとが化合して固体ＴｉＡｌ₃ が生成する反応の発熱ピーク（６１７℃で開始）、(2) Ａｌが溶融する吸熱ピーク（６５７℃で開始）、(3) 液体Ａｌと固体Ｔｉとが化合して固体ＴｉＡｌ₃ が生成する反応の発熱ピーク（６６７℃で開始し７４７℃で終了）である。
【００２４】
更に温度上昇に伴い、(4) および(5) の反応により固体ＴｉＡｌ₃ と固体Ａｌ₄ Ｃ₃ または固体Ｃとが化合して固体ＴｉＣが生成する発熱ピークと中間生成物の生成・分解による発熱および吸熱ピークが８８２℃〜９９２℃の温度領域に観察される。
本発明においては、成形体を不活性雰囲気中にて急速加熱することにより、成形体中でＡｌまたはＡｌ合金の融点（反応(2) ）直近で起きるＴｉＡｌ₃ 生成反応（反応(1) 、反応(3) ）を生じさせ、このＴｉＡｌ₃ 生成反応(1) (3) の発熱により成形体を自動的に急速昇温させて成形体中でＴｉＣ粒子生成反応（反応(4) 、反応(5) ）を生じさせる。
【００２５】
そのために、急速加熱の加熱速度は、ＴｉＡｌ₃ 生成反応(1) (3) で発生する熱から外部への放散および生じうる吸熱反応（反応(2) 等）による熱損失を差し引いた残余の熱により、成形体全体がＴｉＣ粒子生成反応(4) (5) の生じる温度（８８２℃〜９９２℃）にまで自動的に昇温できるように、十分な短時間でＴｉＡｌ₃ 生成反応(1) (3) を進行させる加熱速度とする。また、急速加熱による加熱到達温度はＴｉＡｌ₃ 生成反応(1) (3) の生じ得る下限温度（＝反応(1) の起きる下限温度６１７℃）からＴｉＣ粒子生成反応(4) (5) の生じ得る上限温度（＝反応(5) の起きる上限温度９９２℃）までの範囲内とする。
【００２６】
上記のように急速加熱を行うことにより、本来は図１のように各々独立した反応である(1) 〜(5) の反応が連続的に生じ、見掛け上一つの発熱反応となり、反応(1) の開始から１〜２分程度の極めて短時間で反応(5) まで完了する。
図２に、本発明による急速加熱を行った場合の時間に対するＤＴＡ挙動を、図１のような緩速加熱時の挙動と比較して模式的に示す（横軸は時間である。）
このような急速加熱は、誘導加熱により容易に行うことができ、加熱装置を到達温度７００℃に設定し、加熱速度２０℃／min で行えば反応(1) 〜(5) を自動的に連続進行させるには十分である。この場合、設定温度の７００℃に到達する直前（６１７℃）から反応(1) により発熱が始まり、成形体の温度は実際には設定温度の７００℃で停留することなく連続昇温が進行し、１〜２分程度で１２００℃程度まで到達する。反応(5) によるＴｉＣ生成が完了すると、成形体は急速に温度降下する。
【００２７】
上記のように急速加熱により発熱反応を誘起して短時間でＴｉＣ粒子の生成を完遂させる上で、含浸を行うことは下記２点で決定的に重要である。
（１）化合物粒子の微細化
含浸により成形体中の空隙は殆どＡｌで充填される。これにより、Ｔｉ粉末粒子、Ｃ粉末粒子、Ａｌとの化合物粒子の間には含浸されたＡｌが介在するため、急速加熱による反応中に各生成物粒子、特に最終的なＴｉＣ粒子同士の凝集による粗大化が防止され、微細なＴｉＣ粒子が分散した金属基複合材料が得られる。粒子の微細分散は、この金属基複合材料を直接実用に供する場合には優れた機械特性を付与するし、また、この金属基複合材料を粒子添加材として溶湯中に導入する場合には粒子が溶湯中に容易に微細分散し、凝固により得られる金属基複合材料の機械特性の向上に寄与する。
【００２８】
（２）急速加熱時の反応促進
含浸時にＡｌ溶湯とＴｉ粉末粒子とが反応してＴｉ粒子の周囲に微細なＴｉＡｌ₃ 粒子が生成し、急速加熱時に最終反応であるＴｉＡｌ₃ ＋Ｃ→ＴｉＣ＋３Ａｌが促進される。これにより見掛け上の反応開始温度が低下し、本発明の急速加熱によるＴｉＣ粒子の効率的な生成を可能とする。
【００２９】
また、含浸により成形体中の空隙が殆どＡｌで充填されるので、急速加熱時に成形体全体に渡って熱伝導が促進され反応が促進される。
このように本発明によれば、従来のように高温・長時間の加熱を必要とせず、例えば分単位の極めて短時間でＴｉＣ粒子の生成反応を完遂させられる。
更に、従来のような重力偏析等の問題が生じないので、成形体のサイズをかなり大きくすることができる。
【００３０】
すなわち、従来の高温・長時間の加熱では、一因としては、マトリクス成分であるＡｌまたはＡｌ合金が溶融状態で長時間維持されるので、各粉末からの成分元素や生成した化合物粒子の重力偏析が生じ易いため、またもう一つの原因としては、成形体のサイズが大きくなると温度分布が不均一になるため、サイズの大きい成形体では体積全体に渡ってＴｉＣ粒子の生成反応を完遂させることができなくなる。
【００３１】
本発明では、成形体全体を加熱反応開始温度まで急速に、すなわち短時間加熱して、ＴｉＣ生成に到る各反応を自動進行させることにより、上記従来の問題が解消され、成形体のサイズに対する制限が大幅に緩和される。
第１観点のＴｉＣ粒子に代えて、第２、第３、第４、第５観点によりＺｒＣ粒子、ＨｆＣ粒子、ＮｂＣ粒子、ＴｉＢ₂ 粒子を生成させる場合にも、同様な原理により極めて短時間で大きな成形体中に各粒子を生成させることができる。
【００３２】
【実施例】
〔実施例１〕
第１発明の第１態様に従って、純アルミニウム中にＴｉＣ粒子を生成させた金属基複合材料を下記の手順で製造した。ＴｉＣのＣ源としてＣ粉末を用いた。
〔成形体の作製〕
純アルミニウム粉（−４５μｍ、９９．３％）、純チタン粉（−４５μｍ、９９．４％）、純黒鉛粉（−４５μｍ、９９．４％）をそれぞれ７ｇ、１１．２ｇ、２．８ｇ秤量して混合し、成形圧７ｔ／cm² でφ３０mmの円柱状成形体を作製した。得られた成形体の空隙率は約１０％であった。
【００３３】
〔アルミニウム溶湯の含浸〕
上記の成形体を７３０℃の純アルミニウム溶湯（純度９９．９％）に３０秒浸漬させた後、速やかに溶湯より取り出し、成形体の空隙中に純アルミニウム溶湯を含浸させた。この含浸により、成形体の重量は含浸前の１８．５ｇから約３０ｇに増加した。
【００３４】
含浸したアルミニウム溶湯は、成形体の内部の密着性・熱伝導性を高める効果に加え、チタン粉末粒子と反応してＴｉ粒子の周囲に微細なＡｌ₃ Ｔｉ粒子を生成し、後にの急速加熱によるＴｉＣ生成までの反応を効率良く進め、ＴｉＣ粒径の微細化に寄与する。
図３に、含浸後の成形体の顕微鏡組織の一例を示す。Ａｌマトリクス（黒色）中に分散したＴｉ粒子（白色）の周囲に１μｍ程度の微細なＴｉＡｌ₃ （灰色）が多数生成している。
【００３５】
これ対して、作製した含浸なしの成形体は、後の高周波加熱において加熱効率が著しく低く、健全なＡｌ−ＴｉＣペレットが得られなかった。
また、同じ比較材を、５℃／min の昇温速度で１３００℃まで昇温させてＴｉＣを生成させたが、生成したＴｉＣ粒子は平均粒径３μｍと大きかった。
〔ＴｉＣ粒子の生成〕
ＴｉＣ粒子生成のための急速加熱を、周波数３６００Ｈｚ、出力２０ｋＷの高周波電動発電機を備えた真空溶解炉を用いて行った。
【００３６】
炉内に上記含浸後の成形体を７個重ねて装入し（計２１０ｇ）、炉内を１０^-2Torrまで真空引きした後、Ａｒガスを−２０ｃｍＨｇまで導入し、高周波誘導加熱により急速加熱を行った。
加熱速度は、高周波出力の設定により制御した。表１に示したように、試料の加熱速度および装置の設定到達温度はそれぞれ、発明例１：３０℃／min ，７００℃、発明例２：５０℃／min ，８００℃、発明例３：１００℃／min ，６５０℃とした。
【００３７】
比較例１は、加熱設定温度を本発明の範囲（ＴｉＡｌ₃ 生成反応下限温度である６１７℃以上）より低い６００℃とした以外は、発明例１と同じ条件で処理を行った例である。
比較例２〜５では、加熱速度が本発明の範囲（一旦ＴｉＡｌ₃ 生成反応が開始した後はＴｉＣ粒子生成反応の生じる温度にまで自動的に昇温できる加熱速度）より遅い例として、従来と同様に通常の電気炉にて加熱を行った。加熱速度は炉の能力上限一杯の１０℃／min とし、加熱設定温度は比較例２では８００℃、比較例３、４、５では１２００℃とした。加熱保持は行なわず、設定温度到達後に炉内で冷却した。
【００３８】
比較例６は、含浸を行わず、本発明の範囲の加熱条件で高周波加熱を行った例である。
試料サイズは、比較例２、３では３０ｇ（成形体１個）、比較例４では６０ｇ（成形体２個）、比較例５では９０ｇ（成形体３個）と変化させた。比較例６の試料サイズは６０ｇ（成形体２個）とした。
【００３９】
本発明による急速加熱を行った発明例１、２、３では、昇温過程において６００℃を超えた温度付近から急激な試料温度の上昇が始まり、２０秒〜４０秒でそれぞれ１２１５℃、１２３５℃、１３２０℃に達し、その後、急激に温度が降下した。これは、反応(1) 〜(5) が連続的に生じることにより自己発熱で試料の温度が短時間で上昇し、最後の反応(5) の完了とともに温度が急速に降下したためである。このように、反応による自己発熱の方が高周波装置による人為的な加熱を遙かに上回るため、本実施例の範囲内の設定温度であれば、ＴｉＣ生成に要する時間はほぼ同程度の極めて短時間である。
【００４０】
発明例１〜３および比較例１〜６による処理後の試料について、Ｘ線回折による相同定およびＳＥＭミクロ組織写真の画像処理による粒径測定を行った。これらの調査結果も併せて表１に示す。
本発明による急速加熱を行った発明例１〜３は、Ａｌマトリクス中に平均粒径０．２μｍのＴｉＣ粒子が均一に分散した組織であった。他の相は検出されなかった。
【００４１】
比較例１では、加熱速度は発明例１と同等であったが、加熱設定温度６００℃が反応(1) のＡｌ₃ Ｔｉ生成反応開始温度６１７℃に達しなかったため、この反応による自己発熱が起きず、その後の昇温はなく試料到達温度は加熱設定温度の６００℃止まりであり、ＴｉＣの生成には到らなかった。処理後の試料は、含浸によるＡｌ凝固相、Ａｌ粒子（含浸時未溶解分）、Ｔｉ粒子、Ｃ粒子、ＴｉＡｌ₃ 粒子が混在した組織であった。
【００４２】
比較例２は、加熱設定温度は８００℃であり反応(1) (3) によるＴｉＡｌ₃ 生成による発熱はあったが、加熱速度が本発明の範囲より遅かったため、反応(1) (3) から反応(4) (5) が連続して生ずることがなく、ＴｉＣは生成しなかった。処理後の試料は、Ａｌ凝固相中にＴｉ、Ｃ、ＴｉＡｌ₃ の各粒子が混在した組織であった。
【００４３】
比較例３、４、５は、本出願人が開発した日本特許第２７３４８９１号による従来の処理条件を満たしており、発明例１〜３と同様にＡｌマトリクス中に平均粒径０．２μｍのＴｉＣ粒子が均一に分散した組織が得られた。ただし、試料サイズが３０ｇの比較例３ではＡｌ相とＴｉＣ粒子のみが観察されたが、試料サイズを６０ｇ、９０ｇと増加させた比較例４、５では、Ａｌ相およびＴｉＣ粒子以外にＴｉＡｌ₃ 相が混在しており、その量は試料サイズの増加に伴い増加していた。処理炉内で試料の下部であった部位にＴｉＡｌ₃ 粒子が存在する傾向が強かったことから、その存在理由は次のように考えられる。
【００４４】
すなわち、従来のような加熱保持によるＴｉＣ生成処理においては、（Ａ）反応(1) 〜(5) が全て完了するのに要する時間が長いため、１２００℃で溶融状態にあるＡｌの溶湯中で重力偏析により組成のばらつきが生じ、反応(1) (3) で生成した中間生成物であるべきＴｉＡｌ₃ が反応(4) (5) へ進行せずに残留したか、（Ｂ）試料サイズが大きいため温度分布が不均一になり易く、局所的に反応の進行が不完全になったか、あるいはこれら両者が併行したか、である。
【００４５】
発明例１〜３では、試料全体を少なくとも反応(1) が生じ得る温度にまで急速加熱し、以降の反応(2) 〜(5) を自動的に連続進行させることにより、短時間でＴｉＣ生成反応(5) まで完全に行わせるので、上記のような長時間加熱保持による重力偏析や温度不均一によるＴｉＡｌ₃ の残留が起きることがない。
更に、発明例１〜３による成形体総重量が増加してもＴｉＣ粒径は平均０．２μｍであり、表１には示していないが粒径は均一で０．３μｍ以上のＴｉＣ粒子は存在しない。
【００４６】
これに対し、従来の高温熱処理を行った比較例３〜５では、ＴｉＣ粒径は平均０．２μｍではあるが、０．１μｍ〜１．５μｍの粒径分布が認められた。
このように本発明により均一なＴｉＣ粒径が得られたのは、ＴｉＣ生成が極めて短時間で完了したことに加え、成形体内で温度差が殆ど生じないためであると考えられる。
【００４７】
【表１】

【００４８】
〔実施例２〕
第１発明の第１態様に従って、ＴｉＣ粒子添加材として、純アルミニウム中にＴｉＣ粒子を生成させた金属基複合材料を下記の手順で製造した。ＴｉＣのＣ源としてＳｉＣ粉末を用いた。
〔成形体の作製〕
純アルミニウム粉（−４５μｍ、９９．３％）、純チタン粉（−４５μｍ、９９．４％）、ＳｉＣ粉（１３μｍ、５０μｍ）をそれぞれ表２の配合で混合し、成形圧７ｔ／cm² でφ３０mmの円柱状成形体を作製した。発明例１および３は、全てのＳｉＣがＴｉと反応するモル比として配合であり、ＳｉＣ粉の粒径を２水準とした。発明例２は、Ｔｉとの反応に必要な量の２倍のモル比のＳｉＣ量とした。得られた成形体の空隙率は約７％であった。
【００４９】
【表２】

【００５０】
〔アルミニウム溶湯の含浸〕
上記の成形体を７３０℃の純アルミニウム溶湯（純度９９．９％）に３０秒浸漬させた後、速やかに溶湯より取り出し、成形体の空隙中に純アルミニウム溶湯を含浸させた。この含浸により、成形体の重量は、発明例１では含浸前の２７．６ｇから約３１ｇに、発明例２では３７ｇから４２ｇに、発明例３では２７．６ｇから３０ｇに、それぞれ増加した。含浸後の成形体中には、Ａｌ、Ｔｉ、ＳｉＣ、Ａｌ₃ Ｔｉが存在していた。Ａｌ₃ Ｔｉは、Ｔｉ粒子の周囲に微細粒（直径１μｍ程度）として生成していた。
【００５１】
〔ＴｉＣ粒子の生成〕
ＴｉＣ粒子生成のための急速加熱を、実施例１と同じ真空溶解炉を用いて行った。
炉内に上記含浸後の成形体を、表３に示した重量・個数で炉内に装入し、炉内を１０^-2Torrまで真空引きした後、Ａｒガスを−２０ｃｍＨｇまで導入し、高周波加熱により急速加熱を行った。
【００５２】
加熱速度は、高周波出力の設定により制御した。試料の加熱速度および装置の設定到達温度は全て１００℃／min 、７００℃とした。
発明例１〜３のいずれの場合も、昇温過程において７００℃付近から急激な試料温度の上昇が始まり２０秒〜４０秒で約１３００℃に達し、その後、急激に温度が低下した。この急激な昇温は、下記の発熱反応によると考えられる。
【００５３】
Ti＋3Al → TiAl₃
TiAl₃ ＋SiC → 3Al＋TiC ＋Si（＊）
Ti＋SiC → TiC＋Si（＊）
（＊：Ti粉末に対してSiC 粉末の配合量が過剰な場合にSiC が残留)
すなわち、上記の発熱反応が連続的に起きることによる自己発熱で試料の温度が上昇し、極めて短時間でＴｉＣの生成反応が進行したものである。
【００５４】
上記処理後の発明例１〜３の試料について、Ｘ線回折による相同定およびＳＥＭミクロ組織写真の画像処理による粒径測定を行った。これらの調査結果を表３に示す。
【００５５】
【表３】

【００５６】
発明例１〜３のいずれにおいても、Ａｌマトリクス中に平均粒径０．２μｍのＴｉＣ粒子が均一に分散した組織であった。また、反応副生成物としてＳｉ相（５〜５０μｍ）が存在するが、ＳｉはＡｌ合金の強度、耐摩耗性、鋳造性を向上させる効果がある。
発明例２においては、過剰に添加したＳｉＣ粒子が残存しており、ＴｉＣ粒子とＳｉＣ粒子の２種類の分散粒子（強化粒子）を有するアルミニウム基複合材料が得られた。
【００５７】
本実施例においては、ＴｉＣ粒子のＣ源として黒鉛粉末に代えてＳｉＣ粉末を用いたことにより下記の点で有利である。
▲１▼ＳｉＣ粉末は黒鉛粉末に比べて価格が数分の１と安価である。
▲２▼ＳｉＣとＴｉとの反応による副生成物であるＳｉは、Ａｌ溶湯の流動性、鋳造性を高める元素であり、成形体をＴｉＣ粒子添加材としてＡｌ溶湯中に添加した際の溶湯中への溶解性とＴｉＣ粒子（およびＳｉＣ粒子）の溶湯中への分散性を高める。Ａｌ−Ｓｉ系２元状態図からも分かるように、純Ａｌの融点６６０℃はＳｉの添加により最低５７７℃まで低下するので、この低融点化による直接的な溶解性および分散性の向上効果も得られる。
【００５８】
発明例２のように、意図的にＳｉＣをＴｉに対して過剰量とすることにより、ＴｉＣ生成処理後の成形体中にＳｉＣを共存させると、ＴｉＣ粒子よりもＳｉＣ粒子の方がＡｌ溶湯中での分散性が高いことを、下記のように利用できる利点がある。
ＴｉＣ粒子を生成させた成形体を添加する溶湯の合金組成が、例えばＡｌ−Ｓｎ−Ｓｉ等である場合、成形体の添加および溶解後の凝固時に、ＴｉＣ粒子がＡｌ相から排出されて最終凝固部である粒界に偏析する傾向がある。偏析によりＴｉＣ粒子は本来の分散効果を十分に発揮できず、複合材料として所期の強度特性が得られない場合がある。特に、偏析が顕著な場合には、粒界に偏析したＴｉＣ粒子により粒界脆化が起きてしまい、むしろ強度が低下する危険もある。
【００５９】
このような組成のＡｌ合金に対しては、ＴｉＣ粒子とＳｉＣ粒子が共存することにより、ＴｉＣ粒子よりも分散性の高いＳｉＣ粒子により分散強化を行い、同時に、ＴｉＣ粒子によりＡｌマトリクスの微細化と耐摩耗性向上を行うことができる。
〔実施例３〕
第２発明の第１態様に従い、下記の手順により、ＴｉＣ粒子含有成形体をＭｇまたはＭｇ合金の溶湯に添加して、金属基複合材料を製造した。
【００６０】
純ＭｇおよびＡＺ９１Ｍｇ合金をそれぞれＳＦ₆ ガス雰囲気中で溶解した。
得られたＭｇまたはＭｇ合金の溶湯に、上記発明例１および発明例３により作成したＴｉＣ粒子含有成形体を添加し、５分間の機械的攪拌を行った後、ＪＩＳ４号舟金型に７５０℃で鋳造した。成形体の添加量を種々に変えることにより、鋳造材中のＴｉＣ含有量を０〜５ vol％の範囲で変化させた。各鋳造材について、硬さ、引張特性、耐摩耗性を調べた結果を図４〜７に示す。純ＭｇおよびＡＺ９１Ｍｇ合金のいずれについても、ＴｉＣ粒子による分散強化が得られた。なお、引張強度特性および耐摩耗特性は下記条件での試験により求めた。
【００６１】
＜引張試験条件＞
試験片形状：平行部、φ５×２５（mm）
引張速度：１mm／min
＜摩耗試験条件＞
試験片形状：１５．７×１０．１×６．３
相手材形状：φ３５リング状
相手材材質：ＳＵＪ−２
回転速度：１６０rpm
荷重：１９６Ｎ
試験時間：６０分
潤滑：５Ｗ−３０基油
また、ＴｉＣ粒子の添加により鋳造材の結晶粒が微細化した。図８に純Ｍｇ鋳造材の鋳造組織を示す。ＴｉＣ粒子添加なしの鋳造材（Ａ）に比べて、上記のようにＴｉＣ粒子を１ vol％添加した鋳造材（Ｂ）は鋳造組織が顕著に微細化している。
【００６２】
従来、ＭｇおよびＭｇ合金の鋳造組織微細化には、ヘキサクロロエタン（Ｃ₂ Ｃｌ₆ ）等が微細化材として広く用いられており、微細化機構としてはＡｌ₄ Ｃ₃ による異種核生成説が一般的に取られている。
本発明によれば、分散強化による強度特性の向上と同時に鋳造組織の微細化による強度特性および耐食性の向上が可能になる。
【００６３】
〔実施例４〕
第１発明の第２態様に従って、純アルミニウム中にＺｒＣ粒子を生成させた金属基複合材料を下記の手順で製造した。
〔成形体の作製〕
純アルミニウム粉（−４５μｍ、９９．９９％）、純ジルコニウム粉（−１４７μｍ、９９．９％）、純黒鉛粉（−４５μｍ、９９％）をそれぞれ７ｇ、１６．８５ｇ、２．２２ｇ秤量して混合し、成形圧７ｔ／cm² でφ３０mmの円柱状成形体を作製した。得られた成形体の空隙率は約３％であった。
【００６４】
この際、Ｚｒ粉末とＣ粉末との混合比はＺｒＣの化学量論比（モル比）に対応させることが望ましい。Ｚｒ粉末およびＣ粉末とＡｌ粉末との混合比は特に限定されない。粉末の混合比は最終的に作成するＺｒＣ粒子含有成形体の目標ＺｒＣ濃度に応じて調整することができる。
〔アルミニウム溶湯の含浸〕
上記の成形体を７３０℃の純アルミニウム溶湯（純度９９．９９％）に３０秒浸漬させた後、速やかに溶湯より取り出し、成形体の空隙中に純アルミニウム溶湯を含浸させた。この含浸により、成形体の重量は含浸前の２６．０７ｇから約５０ｇに増加した。比較のため、含浸を行わない試料も用意した。
【００６５】
〔ＺｒＣ粒子の生成〕
ＺｒＣ粒子生成のための急速加熱を、実施例１と同じ真空溶解炉を用いて高周波誘導加熱により行った。ただし、比較のため通常の電気炉による加熱も行った。生成粒子について、Ｘ線回折による相同定およびＳＥＭミクロ組織写真の画像処理による粒径測定を行った。表４に、加熱条件および生成相を示す。
【００６６】
【表４】

【００６７】
〔金属溶湯への添加〕
第２発明の第２態様に従って、発明例１により作製したＺｒＣ粒子含有成形体を、８００℃に保持したＡｌ−Ｓｉ合金（ＡＣ８Ａ）の溶湯（重量５００ｇ）中に添加し（添加量：４０ｇ）、５分間攪拌した後、溶湯温度７５０℃で、８０℃に予熱したＪＩＳ４号舟金型に鋳造した。比較のため、上記添加を行わずに同様に鋳造を行った。ＺｒＣ粒子の添加により、硬さ、耐摩耗性、引張強さが向上することを確認した。
【００６８】
上記ＺｒＣ粒子を添加した合金溶湯をアトマイズすることにより、ＺｒＣ粒子含有金属基複合材料粉末を作製することができる。
ＺｒＣ粒子はＡｌ合金溶湯に溶け込まないため、ＺｒＣ粒子の添加量を増加することにより、更に高強度の金属基複合材料を得ることもできる。
〔実施例５〕
第１発明の第３態様に従って、純アルミニウム中にＨｆＣ粒子を生成させた金属基複合材料を下記の手順で製造した。
【００６９】
〔成形体の作製〕
純アルミニウム粉（−４５μｍ、９９．９９％）、純ハフニウム粉（−４５μｍ、９８％）、純黒鉛粉（−４５μｍ、９９％）をそれぞれ７ｇ、３１．７３ｇ、２．１４ｇ秤量して混合し、成形圧７ｔ／cm² でφ３０mmの円柱状成形体を作製した。得られた成形体の空隙率は約６％であった。
【００７０】
この際、Ｈｆ粉末とＣ粉末との混合比はＨｆＣの化学量論比（モル比）に対応させることが望ましい。Ｈｆ粉末およびＣ粉末とＡｌ粉末との混合比は特に限定されない。粉末の混合比は最終的に作成するＨｆＣ粒子含有成形体の目標ＨｆＣ濃度に応じて調整することができる。
〔アルミニウム溶湯の含浸〕
上記の成形体を７３０℃の純アルミニウム溶湯（純度９９．９９％）に３０秒浸漬させた後、速やかに溶湯より取り出し、成形体の空隙中に純アルミニウム溶湯を含浸させた。この含浸により、成形体の重量は含浸前の４０．８７ｇから約６５ｇに増加した。
【００７１】
〔ＨｆＣ粒子の生成〕
ＨｆＣ粒子生成のための急速加熱を、実施例１と同じ真空溶解炉を用いて高周波誘導加熱により行った。ただし、比較のため通常の電気炉による加熱も行った。生成粒子について、Ｘ線回折による相同定およびＳＥＭミクロ組織写真の画像解析による粒径測定を行った。表５に、加熱条件および生成相を示す。
【００７２】
【表５】

【００７３】
ＨｆＣ粒子の生成は、約６５０℃以上の温度域で、低温側から順に下記の反応が起きることによる。
Hf ＋3Al → HfAl₃ (1)
HfAl₃ ＋C → HfC＋ 3Al (2)
粉末成形体にＡｌ溶湯を含浸すると、Ｈｆ粉末粒子とＡｌ溶湯とが上記(1) の反応をして、Ｈｆ粉末粒子の周囲に微細なＨｆＡｌ₃ 粒子が生成する。この状態で次の急速加熱をすると(2) の反応が促進される。
【００７４】
反応(2) によるＨｆＣ生成には、通常は１０００℃以上の高温域まで加熱する必要がある。本発明に従って昇温速度２０℃／分以上で急速加熱することにより、反応(1) が起きる約６５０℃まで加熱すれば、反応(1) による自己発熱で自動的に昇温し、反応(2) が起きてＨｆＣが生成する。要した加熱時間は２０秒〜２分であった。
【００７５】
本実施例では、加熱雰囲気として不活性ガス雰囲気を用いたが、例え大気中で加熱しても、本発明の急速加熱であれば成形体の表面が僅かに酸化されるだけなので、問題はない。
〔金属溶湯への添加〕
第２発明の第３態様に従って、発明例１により作製したＨｆＣ粒子含有成形体を、８００℃に保持したＡｌ−Ｓｉ合金（ＡＣ８Ａ）の溶湯（重量５００ｇ）中に添加し（添加量：４５ｇ）、５分間攪拌した後、溶湯温度７５０℃で、８０℃に予熱したＪＩＳ４号舟金型に鋳造した。比較のため、上記添加を行わずに同様に鋳造を行った。ＨｆＣ粒子の添加により、硬さ、耐摩耗性、引張強さが向上することを確認した。
【００７６】
上記ＨｆＣ粒子を添加した合金溶湯をアトマイズすることにより、ＨｆＣ粒子含有金属基複合材料粉末を作製することができる。
ＨｆＣ粒子はＡｌ合金溶湯に溶け込まないため、ＨｆＣ粒子の添加量を増加することにより、更に高強度の金属基複合材料を得ることもできる。
〔実施例６〕
第１発明の第４態様に従って、純アルミニウム中にＮｂＣ粒子を生成させた金属基複合材料を下記の手順で製造した。
【００７７】
〔成形体の作製〕
純アルミニウム粉（−４５μｍ、９９．９９％）、純ニオブ粉（−１５０μｍ、９９．９％）、純黒鉛粉（−４５μｍ、９９％）をそれぞれ７ｇ，１９．４９ｇ，２．５２ｇ秤量して混合し、成形圧７ｔ／cm² でφ３０mmの円柱状成形体を作製した。得られた成形体の空隙率は約１０％であった。
【００７８】
この際、Ｎｂ粉末と黒鉛粉末との混合比はＮｂＣの化学量論比（モル比）に対応させることが望ましい。Ｎｂ粉末および黒鉛粉末とＡｌ粉末との混合比は特に限定されない。粉末の混合比は最終的に作成するＮｂＣ粒子含有成形体の目標ＮｂＣ濃度に応じて調整することができる。
〔アルミニウム溶湯の含浸〕
上記の成形体を７３０℃の純アルミニウム溶湯（純度９９．９９％）に３０秒浸漬させた後、速やかに溶湯より取り出し、成形体の空隙中に純アルミニウム溶湯を含浸させた。この含浸により、成形体の重量は含浸前の２９．０１ｇから約３５ｇに増加した。
【００７９】
〔ＮｂＣ粒子の生成〕
ＮｂＣ粒子生成のための急速加熱を、実施例１と同じ真空溶解炉を用いて高周波誘導加熱により行った。ただし、比較のため通常の電気炉による加熱も行った。生成粒子について、Ｘ線回折による相同定およびＳＥＭミクロ組織写真の画像解析による粒径測定を行った。表６に、加熱条件および生成相を示す。
【００８０】
【表６】

【００８１】
ＮｂＣ粒子の生成は、約６５０℃以上の温度域で、低温側から順に下記の反応が起きることによる。
Nb ＋3Al → NbAl₃ (1)
NbAl₃ ＋C → NbC＋ 3Al (2)
粉末成形体にＡｌ溶湯を含浸すると、Ｎｂ粉末粒子とＡｌ溶湯とが上記(1) の反応をして、Ｎｂ粉末粒子の周囲に微細なＮｂＡｌ₃ 粒子が生成する。この状態で次の急速加熱をすると(2) の反応が促進される。
【００８２】
反応(2) によるＮｂＣ生成には、通常は１０００℃以上の高温域まで加熱する必要がある。本発明に従って昇温速度２０℃／分以上で急速加熱することにより、反応(1) が起きる約６５０℃まで加熱すれば、反応(1) による自己発熱で自動的に昇温し、反応(2) が起きてＮｂＣが生成する。要した加熱時間は２０秒〜２分であった。
【００８３】
本実施例では、加熱雰囲気として不活性ガス雰囲気を用いたが、例え大気中で加熱しても、本発明の急速加熱であれば成形体の表面が僅かに酸化されるだけなので、問題はない。
〔金属溶湯への添加〕
第２発明の第４態様に従って、発明例１により作製したＮｂＣ粒子含有成形 体を、８００℃に保持したＡｌ−Ｓｉ合金（ＡＣ８Ａ）の溶湯（重量５００ｇ）中に添加し（添加量：３５ｇ）、５分間攪拌した後、溶湯温度７５０℃で、８０℃に予熱したＪＩＳ４号舟金型に鋳造した。比較のため、上記添加を行わずに同様に鋳造を行った。ＮｂＣ粒子の添加により、硬さ、耐摩耗性、引張強さが向上することを確認した。
【００８４】
上記ＮｂＣ粒子を添加した合金溶湯をアトマイズすることにより、ＮｂＣ粒子含有金属基複合材料粉末を作製することができる。
ＮｂＣ粒子はＡｌ合金溶湯に溶け込まないため、ＮｂＣ粒子の添加量を増加することにより、更に高強度の金属基複合材料を得ることもできる。
〔実施例７〕
第１発明の第５態様に従って、純アルミニウム中にＴｉＢ₂ 粒子を生成させた金属基複合材料を下記の手順で製造した。
【００８５】
〔成形体の作製〕
純アルミニウム粉（−４５μｍ、９９．９９％）、純チタン粉（−１５０μｍ、９９．４％）、ＡｌＢ₂ 粉（−４５μｍ、９９％）を重量比で５：８：８の割合で混合し、成形圧７ｔ／cm² でφ３０×１０mmの円柱状成形体を作製した。得られた成形体の空隙率は約１０％であった。
【００８６】
この際、Ｔｉ粉末とＡｌＢ₂ 粉末との混合比はＴｉＢ₂ の化学量論比（モル比）に対応させることが望ましい。Ｔｉ粉末およびＡｌＢ₂ 粉末とＡｌ粉末との混合比は特に限定されない。粉末の混合比は最終的に作成するＴｉＢ₂ 粒子含有成形体の目標ＴｉＢ₂ 濃度に応じて調整することができる。
〔アルミニウム溶湯の含浸〕
上記の成形体を７３０℃の純アルミニウム溶湯（純度９９．９９％）に３０秒浸漬させた後、速やかに溶湯より取り出し、成形体の空隙中に純アルミニウム溶湯を含浸させた。この含浸により、成形体の重量は含浸前の２４．８７ｇから約３５ｇに増加した。
【００８７】
〔ＴｉＢ₂ 粒子の生成〕
ＴｉＢ₂ 粒子生成のための急速加熱を、実施例１と同じ真空溶解炉を用いて高周波誘導加熱により行った。ただし、比較のため通常の電気炉による加熱も行った。生成粒子について、Ｘ線回折による相同定およびＳＥＭミクロ組織写真の画像解析による粒径測定を行った。表７に、加熱条件および生成相を示す。
【００８８】
【表７】

【００８９】
ＴｉＢ₂ 粒子の生成は、６１７℃以上の温度域で、低温側から順に下記の反応が起きることによる。
Ti ＋3Al → TiAl₃ (1)
TiAl₃ ＋AlB₂→ TiB₂ ＋ 3Al (2)
AlB₂＋T → Al ＋TiB₂ (3)
粉末成形体にＡｌ溶湯を含浸すると、Ｔｉ粉末粒子とＡｌ溶湯とが上記(1) の反応をして、Ｔｉ粉末粒子の周囲に微細なＴｉＡｌ₃ 粒子が生成する。この状態で次の急速加熱をすると(2) の反応が促進される。
【００９０】
反応(2) および(3) によるＴｉＢ₂ 生成には、通常は１０００℃以上の高温域まで加熱する必要がある。本発明に従って昇温速度２０℃／分以上で急速加熱することにより、反応(1) が起きる６１７℃まで加熱すれば、反応(1) による自己発熱で自動的に昇温し、反応(2) および(3) が起きてＴｉＢ₂ が生成する。生成にようする加熱時間は２０秒〜２分であった。
【００９１】
表７において、発明例１は、アルミニウム溶湯含浸後に高周波加熱により２０℃／分で７００℃まで加熱したもので、７００℃に到達した後は上記反応(1) 〜(3) の連鎖による自己発熱で１３５０℃まで自動的に昇温し、その後急激に温度低下した。７００℃から１３５０℃までの所要時間は約２０秒であった。加熱後の試料は、Ａｌマトリクス中に平均粒径０．２μｍ（最大粒径３μｍ）のＴｉＢ₂ 粒子が均一に分散していた。
【００９２】
比較例１は、アルミニウム溶湯含浸後に高周波加熱により２０℃／分で６００℃まで加熱したもので、反応(1) の温度に達していないため、自己発熱は起きなかった。加熱後の試料は、ＴｉＢ₂ は生成しておらず、原料粉末のＡｌ，Ｔｉ，ＡｌＢ₂ と、含浸時に生成したＡｌ₃ Ｔｉとが混在した状態であった。
比較例２は、アルミニウム溶湯含浸後に電気炉にて１０℃／分で１１００℃まで加熱したもので、１１００℃に到達した後に炉の出力を切って、室温まで炉冷した。加熱後の試料は、Ａｌマトリクス中に平均粒径０．５μｍ（最大粒径３μｍ）のＴｉＢ₂ 粒子が均一に分散していたが、未反応のＡｌＢ₂ およびＴｉが残存していた。
【００９３】
比較例３は、アルミニウム溶湯の含浸を行わずに、比較例２と同様に電気炉で加熱した。ただし、加熱雰囲気は大気中であった。加熱後の試料は、多孔質のＡｌマトリクス中に平均粒径３μｍ（最大粒径１０μｍ）のＴｉＢ₂ 粒子が分散していた。また、試料表面にＡｌ₂ Ｏ₃ 等の酸化物が生成していた。
〔金属溶湯への添加〕
第２発明の第５態様に従って、発明例１により作製したＴｉＢ₂ 粒子含有成形体（ＴｉＢ₂ 濃度：約３３ vol％（４５wt％））を、それぞれ８００℃に保持したＡｌ−４．５Ｃｕ合金およびＡｌ−Ｓｉ合金（ＡＣ８Ａ）の溶湯（重量５００ｇ）中に添加し（ＴｉＢ₂ 添加量：０．０５〜５ vol％）、５分間攪拌した後、溶湯温度７５０℃で、８０℃に予熱したＪＩＳ４号舟金型に鋳造した。比較のため、上記添加を行わずに同様に鋳造を行った。
【００９４】
ＴｉＢ₂ の添加により鋳造材のマクロ組織が著しく微細化されることを確認した。この微細化効果は上記範囲の添加量について同等であった。Ａｌ−４．５Ｃｕ合金の平均結晶粒径は、無添加材で約３mmであったのが、ＴｉＢ₂ 添加材では３０μｍまで微細化されており、結晶粒の形状はデンドライト構造から全て等軸晶に変化していた。ＡＣ８Ａ合金では、デンドライト構造が残っており、結晶粒径の定量的な測定はできなかったが、図９に示すようにＴｉＢ₂ 添加により著しく微細化していることが分かる。
【００９５】
表８に機械的性質を示す。発明例２〜７および比較例４，５は上記鋳造により作製した鋳造材である。発明例８，９は上記ＴｉＢ₂ 添加後の溶湯を下記条件でアトマイズした粉末から熱間押出により作製した粉末冶金材である。引張強度特性および耐摩耗特性は実施例３と同様の試験により評価した。
＜アトマイズ条件＞
溶湯温度：１１００℃
噴霧圧力：９．８MPa(Ｎ₂ ガス）
噴霧ノズル径：φ２mm
＜熱間押出条件＞
アトマイズ粉末３０ｇをφ３０mmの銅缶に入れ、３ton ／cm² の圧力でプリフォームを作製し、これを窒素ガス雰囲気中で１時間加熱して脱気した後、間接押出を行った。
【００９６】
温度：４００℃
押出比：１２
ラム速度：０．２mm／秒
【００９７】
【表８】

【００９８】
表８の結果から、鋳造材の全てにおいて、ＴｉＢ₂ 添加により強度と延性が大幅に向上していることが分かる。このように本発明は、組織微細化と分散強化とにより、強度と延性を同時に向上させることができるという、顕著な効果が得られる。
粉末冶金材についても、高い強度と延性が両立できることが分かる。本実施例では、鋳造材と同じ組成での評価しか行っていないが、ＴｉＢ₂ 粒子はＡｌ合金溶湯に溶け込まないため、ＴｉＢ₂ 粒子の添加量を増加することにより、更に高強度の金属基複合材料を得ることもできる。
【００９９】
上記各実施例では、ＡｌまたはＡｌ合金マトリクス中にＴｉＣ、ＺｒＣ、ＨｆＣ、ＮｂＣ、またはＴｉＢ₂ 粒子が分散したＡｌ基複合材料を製造する場合について説明しが、本発明はこれに限定されることなく、急速加熱した際に化合物生成反応の自己発熱により最終的な化合物粒子の生成反応まで連続的に自動進行し得るマトリクス組成および化合物組成であれば、本発明を適用できることは勿論である。
【０１００】
【発明の効果】
以上説明したように、本発明によれば、粉末成形体に溶湯を含浸した後に加熱して分散強化用化合物粒子を生成させる方法を改良し、高温・長時間の加熱を必要とせず極めて短時間の処理で、且つ一度に処理できる成形体のサイズを拡大し、高い生産性で金属基複合材料を製造することができる。
【図面の簡単な説明】
【図１】図１は、Ｔｉ粉、黒鉛粉、Ａｌ粉から成る圧粉成形体にＡｌを含浸させた試料について、常温からゆっくりと昇温させる過程で生ずる発熱ピークと吸熱ピークを示す示差熱分析（ＤＴＡ）チャートである。横軸は温度であり、縦軸は標準試料（測定温度範囲に発熱反応も吸熱反応もない物質）との温度差ΔＴである。
【図２】図２は、本発明の急速加熱時に自己発熱により一連の反応が見掛け上一体として連続的に進行する場合の発熱ピークを、図１のＤＴＡ曲線と対比して模式的に示すグラフである。ただし、横軸は時間である。
【図３】図３は、含浸後の成形体のミクロ組織の一例を示す金属組織写真である。Ａｌマトリクス（黒色）中に分散したＴｉ粒子（白色）の周囲に１μｍ程度の微細なＴｉＡｌ₃ （灰色）が多数生成している。
【図４】図４は、純ＭｇおよびＡＺ９１合金の硬さとＴｉＣ粒子の添加量の関係を示すグラフである。
【図５】図５は、純ＭｇおよびＡＺ９１合金の摩耗深さとＴｉＣ粒子の添加量の関係を示すグラフである。
【図６】図６は、純ＭｇおよびＡＺ９１合金の引張強さとＴｉＣ粒子の添加量の関係を示すグラフである。
【図７】図７は、純ＭｇおよびＡＺ９１合金の伸びとＴｉＣ粒子の添加量の関係を示すグラフである。
【図８】図８は、ＴｉＣ粒子添加（Ａ）ありおよび（Ｂ）なしの純Ｍｇ鋳造材のマクロ組織を示す金属組織写真である。
【図９】図９は、ＴｉＢ₂ 粒子添加（Ａ）ありおよび（Ｂ）なしのＡＣ８Ｃ合金鋳造材のマクロ組織を示す金属組織写真である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a metal matrix composite material containing a large amount of compound particles, and further relates to a method for producing a metal matrix composite material using the above composite material as a base material (compound particle addition medium).
[0002]
[Prior art]
As a method for producing a dispersion strengthened metal matrix composite material, a method described in JP-A-63-83239 is used, for example, from Ti powder particles, C (graphite) powder particles, and Al or Al alloy powder particles. By heating the formed body in an inert atmosphere, a metal matrix composite material in which a large amount of TiC particles are dispersed in a metal matrix made of Al or an Al alloy is produced as a base material (dispersed particle added medium). A method is known in which a material is dissolved in an Al or Al alloy melt and then solidified. According to this method, the content of TiC particles (dispersion strengthening particles) in the final composite material can be controlled to a desired value by the amount of the base material dissolved in the molten metal.
[0003]
However, when the present applicant actually manufactured a TiC particle dispersion-strengthened Al-based composite material according to the above method, it has been found that the above method has the following problems.
(1) Since the base material is porous and has a small specific gravity, it floats on the surface of the molten metal and is difficult to be completely dissolved in the molten metal. (2) Since the base material is porous and has poor heat conduction, it takes a long time for the entire base material to reach the melt temperature and melt. (3) The molten metal is difficult to penetrate into the porous base material due to surface tension and viscosity. (4) Ti particles and C particles are easily in direct contact with each other in the molded body, and TiC particles grow excessively and become coarse. (5) When the molded body is heated, oxygen and nitrogen remaining in the molded body react with Al to cause Al on the surface of the Al particles.₂ O_Three And AlN are generated, which hinders the dissolution of the base material in the molten metal.
[0004]
Therefore, as a method for solving the above problems, the present applicant formed a molded body made of Ti powder or Zr powder, C powder, Al powder or Al alloy powder as disclosed in Japanese Patent No. 2734891, The molded body is impregnated with a molten Al or Al alloy, and the molded body is heated to 1000 to 1800 ° C. in an inert atmosphere to generate TiC particles or ZrC particles in the molded body, and then the molded body is formed. A method has been developed for melting the body in molten Al or Al alloy.
[0005]
According to this method, when impregnating the molten metal into the powder molded body, Ti or Zr acts as a getter that adsorbs oxygen or nitrogen remaining in the voids and lowers the internal pressure of the voids. Therefore, the impregnation can be satisfactorily performed without requiring any pressure. The getter action further adds Al₂ O_Three And AlN are prevented from being produced, so that the solubility is not lowered by the production thereof.
[0006]
Since the molded body thus obtained is a solid state in which the voids are filled with Al or Al alloy, the specific gravity is equivalent to Al or Al alloy molten metal and high thermal conductivity, so that it does not float on the molten metal surface and is molded. The whole body reaches the molten metal temperature in a short time and easily dissolves in the molten metal.
Thus, the method of the above-mentioned Japanese Patent No. 2734891 developed by the present applicant can solve the above-mentioned problems that were unavoidable with the method of the above-mentioned JP-A-63-83239, and into the molten metal. Excellent in ability to easily and efficiently produce a composite material in which fine TiC particles are uniformly dispersed in an Al or Al alloy matrix. It is a method.
[0007]
However, the above method requires heating at a high temperature of 1000 to 1800 ° C. and usually 3 hours or more, and the size of the molded product that can be applied is inevitably limited due to the necessity of preventing gravity segregation and the like, and about 20 to 30 g. Therefore, further improvement has been desired from the viewpoint of productivity.
[0008]
[Problems to be solved by the invention]
The present invention improves the method of generating compound particles in a molded body by impregnating a powder molded body with a molten metal and increasing the size of the molded body that does not require heating at a high temperature for a long period of time. An object of the present invention is to provide a method for producing a metal matrix composite material with high productivity.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, in the method for producing a metal matrix composite material according to the first invention of the present application, compound particles of a first element and a second element are dispersed in a metal matrix made of a metal or a metal alloy. In the method for producing a metal matrix composite material, the following steps:
Forming a molded body comprising the powder of the first element, the powder of the second element or the compound of the second element, and the powder of the metal or metal alloy;
Impregnating the molded body with a molten metal or a metal alloy; and
By rapidly heating the entire impregnated molded body in an inert atmosphere, a combined reaction between the first element and the metal, which is an exothermic reaction, is caused in the molded body. The step of automatically raising the temperature of the molded body to cause the formation reaction of the compound particles in the molded body, wherein the heating rate of the rapid heating is a compound reaction between the first element and the metal It is sufficient that the entire molded body can be automatically heated up to the temperature at which the formation reaction of the compound particles occurs due to the residual heat obtained by subtracting the heat loss from the heat generated by the heat dissipation and the endothermic reaction that may occur. The compound particle has a heating rate that allows the compounding reaction between the first element and the metal to proceed in a short time, and the temperature reached by the rapid heating is lower than the lower limit temperature at which the compounding reaction between the first element and the metal can occur. Maximum temperature at which the formation reaction of Process, which is within the range of up to,
It is characterized by including.
[0010]
Since the metal matrix composite material produced by the method of the first invention can be obtained in a form containing a very large amount of compound particles in the metal matrix, of course, the metal matrix composite material is finally used for special applications such as wear-resistant sliding members. It can be used directly as a typical particle-dispersed metal matrix composite, or compound particles (typically into the metal or alloy melts that make up the matrix to produce the final particle-dispersed metal matrix composite. In particular, it can be used as a particle additive (typically a dispersion strengthened particle introduction medium) for smoothly introducing dispersion strengthened particles.
[0011]
That is, according to the second invention, the metal matrix composite material containing the compound particles produced by the method of the first invention is introduced into a molten metal or metal alloy as a particle additive, and the metal of the metal matrix composite material There is provided a method for producing a metal matrix composite material, wherein a matrix is dissolved in the molten metal and the compound particles are dispersed in the molten metal, and then the molten metal is solidified.
[0012]
A typical metal matrix composite material produced according to the first invention or the second invention is a particle-dispersed metal matrix composite material applied to various applications, and a typical one is a dispersion strengthened metal matrix composite material. is there.
In general, when the metal matrix composite material according to the first invention is introduced as a particle additive into the molten metal in the second invention, the molten metal of the same type as that impregnated in the molded body in the first invention is used. . However, the particle additive may be introduced into a melt of a metal or alloy different from the impregnated metal or impregnated alloy. In this case, a composition obtained by adding an impregnated metal or impregnated alloy component as an alloy component to the molten metal composition is the final metal matrix composition of the metal matrix composite material.
[0013]
According to the first aspect of the first invention, there is provided a method for producing a metal matrix composite material in which TiC particles are dispersed in a metal matrix made of Al or an Al alloy.
That is, the method for producing a metal matrix composite material according to the first aspect of the first invention is a method for producing a metal matrix composite material in which TiC particles are dispersed in a metal matrix made of Al or an Al alloy.
Forming a molded body composed of Ti powder, C powder (graphite powder), and Al or Al alloy powder;
Impregnating the molded body with a molten Al or Al alloy; and
TiAl generated in the compact immediately after the melting point of the Al or Al alloy by rapidly heating the entire impregnated compact in an inert atmosphere._Three Causing the formation reaction, the TiAl_Three A step of automatically raising the temperature of the molded body by heat generation of the formation reaction to generate a TiC particle generation reaction in the molded body, wherein the heating rate of the rapid heating is the TiAl_Three Sufficient so that the entire molded body can be automatically heated up to the temperature at which the TiC particle formation reaction occurs by the residual heat after subtracting heat dissipation from the heat generated in the formation reaction and heat loss due to the endothermic reaction that may occur TiAl in a short time_Three The heating rate at which the production reaction proceeds, and the temperature reached by the rapid heating is the TiAl_Three A step within a range from a lower limit temperature at which the formation reaction can occur to an upper limit temperature at which the TiC particle generation reaction can occur,
It is characterized by including.
[0014]
In the first aspect of the first invention, it is generally desirable that the heating rate of the rapid heating is 20 ° C./min or more. Further, the heating ultimate temperature of the rapid heating is typically TiAl obtained by a combination of solid Al and solid Ti._Three From the minimum temperature 617 ° C. at which the production reaction can occur, solid TiAl_Three Is a temperature within a range up to an upper limit temperature of 992 ° C. at which a solid TiC particle formation reaction due to the reaction of C and solid C can occur. Such rapid heating can be easily realized by induction heating.
[0015]
Moreover, in the 1st aspect of 1st invention, it can replace with C powder and can use SiC powder in order to form a molded object.
Furthermore, according to the second, third, fourth, and fifth aspects of the first invention, ZrC particles, Hf particles, NbC particles, TiB in a metal matrix made of Al or an Al alloy.₂A method for producing a metal matrix composite in which any of the particles are dispersed is provided.
[0016]
The method for producing a metal matrix composite material according to the second aspect of the first invention is a method for producing a metal matrix composite material in which the compound particles made of ZrC are dispersed in the metal matrix made of Al or an alloy of Al. The first element is Zr and the second element is C. In the step of forming the compact, a compact composed of Zr powder, C powder and Al or Al alloy powder is formed.
[0017]
A method for producing a metal matrix composite material according to a third aspect of the first invention is a method for producing a metal matrix composite material in which the compound particles made of HfC are dispersed in the metal matrix made of Al or an alloy of Al. The first element is Hf and the second element is C, and in the step of forming the compact, a compact composed of Hf powder, C powder, and Al or Al alloy powder is formed.
[0018]
A method for producing a metal matrix composite material according to a fourth aspect of the first invention is a method for producing a metal matrix composite material in which the compound particles composed of NbC are dispersed in the metal matrix composed of Al or an alloy of Al. The first element is Nb and the second element is C, and in the step of forming the compact, a compact composed of Nb powder, C powder, and Al or Al alloy powder is formed.
[0019]
According to a fifth aspect of the first invention of the present invention, there is provided a metal matrix composite manufacturing method comprising:₂A method for producing a metal matrix composite material in which the compound particles are dispersed, wherein the first element is Ti and the second element is B, and Ti powder and AlB are formed in the step of forming the molded body.₂Or AlB₁₂It is characterized by forming a compact made of powder and Al or Al alloy powder.
[0020]
In the second, third, fourth, and fifth aspects of the first invention, the heating rate of the rapid heating is generally preferably 20 ° C./min or more. Such rapid heating can be easily realized by induction heating.
According to the first, second, third, fourth, and fifth aspects of the second invention, TiC particles produced by the methods of the first, second, third, fourth, and fifth aspects of the first invention, respectively. , ZrC particles, HfC particles, NbC particles, TiB₂A molded body containing particles is introduced into a molten metal of Al, Al alloy, Mg, or Mg alloy, and the metal matrix of the molded body is dissolved in the molten metal, and the TiC particles, the ZrC particles, and the HfC particles, respectively. , The NbC particles, the TiB₂There is provided a method for producing a particle dispersion-strengthening type metal matrix composite, characterized in that particles are dispersed in the molten metal and then the molten metal is solidified. When a molten metal of Mg or Mg alloy is used, the Al or Al alloy impregnated in the compact forms a part of the alloy component of the Mg-based metal matrix of the metal-based composite material produced according to the second invention.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
The generation principle of the compound particles according to the present invention will be described below using a case where TiC particles are generated in an Al-based matrix as a typical example.
A formed body composed of Ti powder, graphite powder, and Al or Al alloy powder is formed, and the molten body of Al or Al alloy is impregnated into the formed body.
[0022]
Next, when the molded body is heated, the following chemical reactions (1) to (5) occur between Ti, Al, and C during the temperature rising process.

FIG. 1 shows an example in which each of the above reactions is observed by DTA (differential thermal analysis). The figure shows the results of observation at a slow temperature increase rate of about 5 ° C./min so that each reaction can be clearly separated and detected.
[0023]
Two large exothermic peaks that are upward and one large endothermic peak that is sandwiched between them are generated on the left side (lower temperature) in the figure. These peaks are, in order from the low temperature side: (1) Solid Ti and solid Al combine to form solid TiAl_Three Exothermic peak (starting at 617 ° C) of the reaction produced by (2) Endothermic peak (starting at 657 ° C) where Al melts, (3) Liquid Ti and solid Ti combine to form solid TiAl_Three Is an exothermic peak (starting at 667 ° C. and ending at 747 ° C.).
[0024]
As the temperature rises further, solid TiAl is produced by the reactions of (4) and (5)._Three And solid Al_Four C_Three Alternatively, an exothermic peak in which solid C is combined to form solid TiC and an exothermic and endothermic peak due to generation / decomposition of an intermediate product are observed in a temperature range of 882 ° C. to 992 ° C.
In the present invention, by rapidly heating the molded body in an inert atmosphere, TiAl that occurs immediately in the molded body at the melting point of Al or Al alloy (reaction (2))._Three Formation reaction (reaction (1), reaction (3))_Three Formation reaction (1) The formed body is automatically heated rapidly by the heat generated in (3) to cause TiC particle formation reaction (reaction (4), reaction (5)) in the formed body.
[0025]
Therefore, the heating rate of rapid heating is TiAl_Three Formation reaction (1) The heat generated in (3) is dissipated to the outside and the remaining heat minus the heat loss due to the endothermic reaction that can occur (reaction (2), etc.) causes the entire compact to generate TiC particle formation reaction (4 ) TiAl in a sufficiently short time so that the temperature can be automatically raised to the temperature (882) to 992 ° C._Three The heating rate is such that the production reaction (1) (3) proceeds. Also, the temperature reached by rapid heating is TiAl_Three From the lower limit temperature at which the formation reaction (1) (3) can occur (= the lower limit temperature at which the reaction (1) occurs 617 ° C.) to the upper limit temperature at which the TiC particle formation reaction (4) (5) can occur (= the occurrence of the reaction (5)) Within the range up to an upper limit temperature of 992 ° C.
[0026]
By carrying out rapid heating as described above, the reactions (1) to (5), which are originally independent reactions as shown in FIG. 1, occur continuously, and apparently become one exothermic reaction. ) The reaction (5) is completed in a very short time of about 1 to 2 minutes from the start of the reaction.
FIG. 2 schematically shows the DTA behavior with respect to time when the rapid heating according to the present invention is performed in comparison with the behavior during the slow heating as shown in FIG. 1 (the horizontal axis is time).
Such rapid heating can be easily performed by induction heating. If the heating device is set to an ultimate temperature of 700 ° C. and the heating rate is 20 ° C./min, the reactions (1) to (5) are automatically continued. It is enough to make it progress. In this case, heat generation starts from the reaction (1) immediately before reaching the set temperature of 700 ° C. (617 ° C.), and the temperature of the molded body actually increases continuously without stopping at the set temperature of 700 ° C. The temperature reaches about 1200 ° C. in about 1 to 2 minutes. When the formation of TiC by reaction (5) is completed, the temperature of the compact rapidly decreases.
[0027]
As described above, in order to induce an exothermic reaction by rapid heating and complete the production of TiC particles in a short time, it is critically important to perform impregnation in the following two points.
(1) Refinement of compound particles
Due to the impregnation, the voids in the molded body are almost filled with Al. Thereby, since impregnated Al is interposed between Ti powder particles, C powder particles, and compound particles with Al, each product particle, particularly the final TiC particles are aggregated during the reaction by rapid heating. It is possible to obtain a metal matrix composite material in which coarsening is prevented and fine TiC particles are dispersed. The fine dispersion of the particles gives excellent mechanical properties when the metal matrix composite material is directly put into practical use, and when the metal matrix composite material is introduced into the molten metal as a particle additive, the particles are not dispersed. It is finely dispersed in the molten metal and contributes to improving the mechanical properties of the metal matrix composite material obtained by solidification.
[0028]
(2) Promotion of reaction during rapid heating
During impregnation, the molten Al and Ti powder particles react to form fine TiAl around the Ti particles._Three TiAl is the final reaction when particles are produced and rapidly heated_Three + C → TiC + 3Al is promoted. As a result, the apparent reaction start temperature is lowered, and TiC particles can be efficiently produced by rapid heating according to the present invention.
[0029]
Further, since the voids in the molded body are almost filled with Al due to the impregnation, thermal conduction is promoted throughout the molded body during rapid heating, and the reaction is promoted.
As described above, according to the present invention, it is not necessary to perform heating at a high temperature for a long time as in the prior art, and for example, the formation reaction of TiC particles can be completed in an extremely short time of minutes.
Furthermore, since problems such as gravity segregation as in the prior art do not occur, the size of the molded body can be considerably increased.
[0030]
That is, in the conventional high-temperature / long-time heating, one reason is that the matrix component Al or Al alloy is maintained in a molten state for a long time, so that the component elements from each powder and the generated compound particles are gravity segregated. Another cause is that the temperature distribution becomes non-uniform as the size of the compact increases, so that the formation reaction of TiC particles can be completed over the entire volume of the large size compact. become unable.
[0031]
In the present invention, the above-mentioned conventional problem is solved by heating the entire molded body rapidly to the heating reaction start temperature, that is, for a short time, and automatically proceeding with each reaction leading to TiC generation. The restrictions are greatly relaxed.
Instead of the TiC particles according to the first aspect, ZrC particles, HfC particles, NbC particles, TiB according to the second, third, fourth, and fifth viewpoints.₂In the case of generating particles, each particle can be generated in a large molded body in a very short time by the same principle.
[0032]
【Example】
[Example 1]
According to the first aspect of the first invention, a metal matrix composite material in which TiC particles were produced in pure aluminum was produced by the following procedure. C powder was used as the C source of TiC.
[Production of molded body]
Pure aluminum powder (-45 μm, 99.3%), pure titanium powder (-45 μm, 99.4%) and pure graphite powder (-45 μm, 99.4%) were weighed 7 g, 11.2 g and 2.8 g, respectively. And mix, forming pressure 7t / cm² A cylindrical shaped body with a diameter of 30 mm was prepared. The porosity of the obtained molded body was about 10%.
[0033]
[Impregnation of molten aluminum]
The molded body was immersed in a pure aluminum melt (purity 99.9%) at 730 ° C. for 30 seconds, and then quickly removed from the molten metal, and the voids of the molded body were impregnated with the pure aluminum melt. By this impregnation, the weight of the molded body increased from 18.5 g before impregnation to about 30 g.
[0034]
The impregnated molten aluminum has the effect of increasing the adhesion and thermal conductivity inside the molded body, and reacts with the titanium powder particles to form fine Al around the Ti particles._Three Ti particles are generated, and the reaction up to TiC generation by rapid heating later is efficiently advanced to contribute to the refinement of the TiC particle size.
FIG. 3 shows an example of the microstructure of the molded article after impregnation. Fine TiAl of about 1 μm around Ti particles (white) dispersed in an Al matrix (black)_Three Many (gray) are generated.
[0035]
On the other hand, the produced non-impregnated molded body had a remarkably low heating efficiency in the subsequent high-frequency heating, and a sound Al—TiC pellet could not be obtained.
Further, the same comparative material was heated to 1300 ° C. at a temperature rising rate of 5 ° C./min to generate TiC. The generated TiC particles had a large average particle diameter of 3 μm.
[Production of TiC particles]
Rapid heating for generating TiC particles was performed using a vacuum melting furnace equipped with a high-frequency motor generator with a frequency of 3600 Hz and an output of 20 kW.
[0036]
Seven pieces of the above-mentioned impregnated compacts were placed in the furnace in a stacked manner (total 210 g), and the furnace was filled with 10 parts.^-2After evacuating to Torr, Ar gas was introduced to −20 cmHg, and rapid heating was performed by high-frequency induction heating.
The heating rate was controlled by setting the high frequency output. As shown in Table 1, the heating rate of the sample and the set temperature reached by the apparatus are, respectively, Invention Example 1: 30 ° C./min, 700 ° C., Invention Example 2: 50 ° C./min, 800 ° C., Invention Example 3: 100 The temperature was set to 650 ° C./min.
[0037]
In Comparative Example 1, the heating set temperature is within the range of the present invention (TiAl_Three This is an example in which the treatment was carried out under the same conditions as in Invention Example 1 except that the lower temperature was set to 600 ° C., which was lower than the production reaction lower limit temperature of 617 ° C. or higher.
In Comparative Examples 2 to 5, the heating rate is within the range of the present invention (once TiAl_Three After the start of the formation reaction, heating was performed in a normal electric furnace as in the conventional case, as an example slower than the heating rate at which the temperature can be automatically raised to the temperature at which the TiC particle generation reaction occurs. The heating rate was 10 ° C./min, which is the upper limit of the capacity of the furnace, and the heating set temperature was 800 ° C. in Comparative Example 2, and 1200 ° C. in Comparative Examples 3, 4, and 5. Heating and holding were not performed, and cooling was performed in the furnace after reaching the set temperature.
[0038]
Comparative Example 6 is an example in which high-frequency heating was performed under heating conditions within the range of the present invention without impregnation.
The sample size was changed to 30 g (1 molded body) in Comparative Examples 2 and 3, 60 g (2 molded bodies) in Comparative Example 4, and 90 g (3 molded bodies) in Comparative Example 5. The sample size of Comparative Example 6 was 60 g (2 molded bodies).
[0039]
In Invention Examples 1, 2, and 3 in which rapid heating was performed according to the present invention, a rapid increase in sample temperature started from around the temperature exceeding 600 ° C. in the temperature rising process, and 1215 ° C. and 1235 ° C. in 20 to 40 seconds, respectively. 1320 ° C., and then the temperature dropped rapidly. This is because the reaction temperature (1) to (5) is continuously generated, the temperature of the sample rises in a short time due to self-heating, and the temperature rapidly drops with the completion of the last reaction (5). Thus, since the self-heating due to the reaction far exceeds the artificial heating by the high-frequency device, the time required for TiC generation is extremely short, which is almost the same at the set temperature within the range of the present embodiment. It's time.
[0040]
Samples treated according to Invention Examples 1 to 3 and Comparative Examples 1 to 6 were subjected to phase identification by X-ray diffraction and particle size measurement by image processing of SEM microstructure photographs. These survey results are also shown in Table 1.
Inventive Examples 1 to 3, which were rapidly heated according to the present invention, had a structure in which TiC particles having an average particle diameter of 0.2 μm were uniformly dispersed in an Al matrix. No other phase was detected.
[0041]
In Comparative Example 1, the heating rate was the same as that of Invention Example 1, but the heating set temperature of 600 ° C. was the reaction (1) Al._Three Since the Ti generation reaction start temperature did not reach 617 ° C., self-heating due to this reaction did not occur, there was no subsequent temperature rise, and the sample temperature reached 600 ° C., which was the heating set temperature, and TiC was not generated. . Samples after the treatment were Al solidified phase by impregnation, Al particles (undissolved part during impregnation), Ti particles, C particles, TiAl_Three The structure was a mixture of particles.
[0042]
In Comparative Example 2, the heating set temperature is 800 ° C., and TiAl by reaction (1) (3)_Three Although there was an exotherm due to formation, since the heating rate was slower than the range of the present invention, reaction (1) (3) to reaction (4) (5) did not occur continuously, and TiC was not formed. Samples after treatment were Ti, C, TiAl in the Al solidification phase._Three It was a structure in which each particle was mixed.
[0043]
Comparative Examples 3, 4, and 5 satisfy the conventional processing conditions according to Japanese Patent No. 2734891 developed by the present applicant, and TiC having an average particle diameter of 0.2 μm in the Al matrix as in Invention Examples 1 to 3. A structure in which the particles were uniformly dispersed was obtained. However, in Comparative Example 3 in which the sample size was 30 g, only the Al phase and TiC particles were observed, but in Comparative Examples 4 and 5 in which the sample size was increased to 60 g and 90 g, in addition to the Al phase and TiC particles, TiAl_Three The phases were mixed and the amount increased with increasing sample size. TiAl in the lower part of the sample in the processing furnace_Three Since there was a strong tendency for particles to exist, the reason for their existence is considered as follows.
[0044]
That is, in the TiC generation process by heating and holding as in the prior art, since it takes a long time to complete all of the reactions (1) to (5), in the molten Al at 1200 ° C. Gravity segregation causes compositional variation, and TiAl should be an intermediate product generated in reactions (1) and (3)._Three Remains in the reaction (4) or (5) without proceeding, or (B) the sample size is large and the temperature distribution tends to be non-uniform, and the reaction progress is locally incomplete, or both Is that?
[0045]
In Invention Examples 1 to 3, the entire sample is rapidly heated to at least a temperature at which reaction (1) can occur, and subsequent reactions (2) to (5) are automatically and continuously progressed to generate TiC in a short time. Since reaction (5) is completely performed, TiAl due to gravity segregation and temperature non-uniformity due to long-time heating as described above._Three There will be no residue.
Further, even if the total weight of the molded products according to Invention Examples 1 to 3 increases, the average TiC particle size is 0.2 μm, and although not shown in Table 1, there are uniform TiC particles having a particle size of 0.3 μm or more. do not do.
[0046]
On the other hand, in Comparative Examples 3 to 5 in which conventional high-temperature heat treatment was performed, the average particle size distribution of 0.1 μm to 1.5 μm was recognized although the average particle size of TiC was 0.2 μm.
Thus, the reason why the uniform TiC particle size was obtained by the present invention is considered that TiC generation was completed in a very short time and that there was almost no temperature difference in the molded body.
[0047]
[Table 1]

[0048]
[Example 2]
In accordance with the first aspect of the first invention, a metal matrix composite material in which TiC particles were generated in pure aluminum was produced as the TiC particle additive by the following procedure. SiC powder was used as the TiC C source.
[Production of molded body]
Pure aluminum powder (-45 μm, 99.3%), pure titanium powder (-45 μm, 99.4%), SiC powder (13 μm, 50 μm) were mixed in the composition shown in Table 2, respectively, and the molding pressure was 7 t / cm.²A cylindrical shaped body with a diameter of 30 mm was prepared. Invention Examples 1 and 3 were blended as a molar ratio in which all SiC reacts with Ti, and the particle size of the SiC powder was set to two levels. Inventive Example 2 was set to a SiC amount having a molar ratio twice that required for the reaction with Ti. The porosity of the obtained molded body was about 7%.
[0049]
[Table 2]

[0050]
[Impregnation of molten aluminum]
The molded body was immersed in a pure aluminum melt (purity 99.9%) at 730 ° C. for 30 seconds, and then quickly removed from the molten metal, and the voids of the molded body were impregnated with the pure aluminum melt. By this impregnation, the weight of the molded body was increased from 27.6 g before impregnation to about 31 g in Invention Example 1, from 37 g to 42 g in Invention Example 2, and from 27.6 g to 30 g in Invention Example 3. In the molded body after impregnation, Al, Ti, SiC, Al_ThreeTi was present. Al_ThreeTi was generated as fine particles (about 1 μm in diameter) around the Ti particles.
[0051]
[Production of TiC particles]
Rapid heating for generating TiC particles was performed using the same vacuum melting furnace as in Example 1.
The molded article after impregnation described above was charged into the furnace with the weight and number shown in Table 3, and 10% inside the furnace.^-2After evacuating to Torr, Ar gas was introduced to −20 cmHg, and rapid heating was performed by high-frequency heating.
[0052]
The heating rate was controlled by setting the high frequency output. The heating rate of the sample and the set temperature reached by the apparatus were all 100 ° C./min and 700 ° C.
In any case of Invention Examples 1 to 3, the sample temperature started to increase rapidly from around 700 ° C. in the temperature rising process, reached about 1300 ° C. in 20 seconds to 40 seconds, and then the temperature rapidly decreased. This rapid temperature increase is considered to be due to the following exothermic reaction.
[0053]
Ti + 3Al → TiAl_Three
TiAl_Three+ SiC → 3Al + TiC + Si (*)
  Ti + SiC → TiC + Si (*)
(*: SiC remains when the amount of SiC powder is excessive with respect to Ti powder)
That is, the temperature of the sample rises due to self-heating due to the continuous occurrence of the exothermic reaction, and the TiC formation reaction proceeds in an extremely short time.
[0054]
The samples of Invention Examples 1 to 3 after the above treatment were subjected to phase identification by X-ray diffraction and particle size measurement by image processing of SEM microstructure photographs. Table 3 shows the results of these investigations.
[0055]
[Table 3]

[0056]
In any of Invention Examples 1 to 3, the structure was obtained by uniformly dispersing TiC particles having an average particle diameter of 0.2 μm in the Al matrix. Moreover, although Si phase (5-50 micrometers) exists as a reaction by-product, Si has the effect of improving the strength, wear resistance, and castability of the Al alloy.
In Invention Example 2, excessively added SiC particles remained, and an aluminum-based composite material having two kinds of dispersed particles (strengthened particles) of TiC particles and SiC particles was obtained.
[0057]
In this example, the use of SiC powder instead of graphite powder as the C source of TiC particles is advantageous in the following points.
(1) SiC powder is a fraction of the price compared with graphite powder.
(2) Si, which is a by-product of the reaction between SiC and Ti, is an element that improves the fluidity and castability of the Al molten metal. In the molten metal when the compact is added to the Al molten metal as a TiC particle additive. And the dispersibility of TiC particles (and SiC particles) in the melt. As can be seen from the Al-Si binary phase diagram, the melting point of pure Al, which is 660 ° C, decreases to 577 ° C as a result of the addition of Si. can get.
[0058]
As in Invention Example 2, when SiC is intentionally made excessive with respect to Ti, if SiC is allowed to coexist in the formed body after the TiC generation treatment, SiC particles are in the Al melt rather than TiC particles. The high dispersibility in can be used as follows.
When the alloy composition of the molten metal to which the compact that has generated TiC particles is added is, for example, Al-Sn-Si, the TiC particles are discharged from the Al phase during the solidification after the addition and dissolution of the compact. There is a tendency to segregate at the grain boundaries. Due to segregation, the TiC particles cannot sufficiently exhibit the original dispersion effect, and the desired strength characteristics may not be obtained as a composite material. In particular, when segregation is remarkable, grain boundary embrittlement occurs due to TiC particles segregated at the grain boundary, and there is a risk that the strength is rather lowered.
[0059]
For an Al alloy having such a composition, TiC particles and SiC particles coexist to enhance dispersion by SiC particles having higher dispersibility than TiC particles, and at the same time, refinement of the Al matrix by TiC particles. Abrasion resistance can be improved.
Example 3
In accordance with the first aspect of the second invention, the metal-based composite material was manufactured by adding the TiC particle-containing compact to the molten metal of Mg or Mg alloy according to the following procedure.
[0060]
Pure Mg and AZ91Mg alloy are each SF₆Dissolved in a gas atmosphere.
To the obtained molten metal of Mg or Mg alloy, the TiC particle-containing molded body prepared according to Invention Example 1 and Invention Example 3 was added, and after mechanical stirring for 5 minutes, it was applied to a JIS No. 4 boat mold at 750 ° C. Casted with. The TiC content in the cast material was changed in the range of 0 to 5 vol% by changing the amount of the compact added. The results of examining the hardness, tensile properties, and wear resistance of each cast material are shown in FIGS. Dispersion strengthening with TiC particles was obtained for both pure Mg and AZ91Mg alloy. The tensile strength characteristics and wear resistance characteristics were determined by tests under the following conditions.
[0061]
<Tensile test conditions>
Specimen shape: Parallel part, φ5 × 25 (mm)
Tensile speed: 1mm / min
<Wear test conditions>
Test piece shape: 15.7 × 10.1 × 6.3
Opposite material shape: φ35 ring shape
Mating material: SUJ-2
Rotation speed: 160rpm
Load: 196N
Test time: 60 minutes
Lubrication: 5W-30 base oil
Moreover, the crystal grains of the cast material were refined by the addition of TiC particles. FIG. 8 shows a cast structure of a pure Mg cast material. Compared to the cast material (A) without addition of TiC particles, the cast material (B) to which 1 vol% of TiC particles are added as described above has a remarkably refined cast structure.
[0062]
Conventionally, for refinement of cast structure of Mg and Mg alloy, hexachloroethane (C₂Cl₆) Etc. are widely used as a refining material, and the refining mechanism is Al._FourC_ThreeHeterogeneous nucleation theory is generally taken.
According to the present invention, it is possible to improve strength characteristics and corrosion resistance by refinement of a cast structure at the same time as improving strength characteristics by dispersion strengthening.
[0063]
Example 4
According to the second aspect of the first invention, a metal matrix composite material in which ZrC particles were produced in pure aluminum was produced by the following procedure.
[Production of molded body]
Pure aluminum powder (−45 μm, 99.99%), pure zirconium powder (−147 μm, 99.9%), and pure graphite powder (−45 μm, 99%) were weighed 7 g, 16.85 g, and 2.22 g, respectively. Mix, forming pressure 7t / cm²A cylindrical shaped body with a diameter of 30 mm was prepared. The porosity of the obtained molded body was about 3%.
[0064]
At this time, it is desirable that the mixing ratio of the Zr powder and the C powder corresponds to the stoichiometric ratio (molar ratio) of ZrC. The mixing ratio of Zr powder and C powder to Al powder is not particularly limited. The mixing ratio of the powder can be adjusted according to the target ZrC concentration of the ZrC particle-containing molded article to be finally produced.
[Impregnation of molten aluminum]
The molded body was immersed in a pure aluminum melt (purity 99.99%) at 730 ° C. for 30 seconds, and then quickly removed from the molten metal, and the voids of the molded body were impregnated with the pure aluminum melt. By this impregnation, the weight of the molded body increased from 26.07 g before impregnation to about 50 g. For comparison, a sample without impregnation was also prepared.
[0065]
[Generation of ZrC particles]
Rapid heating for generating ZrC particles was performed by high frequency induction heating using the same vacuum melting furnace as in Example 1. However, for the purpose of comparison, heating with a normal electric furnace was also performed. The produced particles were subjected to phase identification by X-ray diffraction and particle size measurement by image processing of SEM microstructure photographs. Table 4 shows the heating conditions and the product phase.
[0066]
[Table 4]

[0067]
[Addition to molten metal]
In accordance with the second aspect of the second invention, the ZrC particle-containing compact produced according to Invention Example 1 was added to a molten Al-Si alloy (AC8A) maintained at 800 ° C. (weight 500 g) (addition amount: 40 g). After stirring for 5 minutes, it was cast into a JIS No. 4 boat mold preheated to 80 ° C. at a molten metal temperature of 750 ° C. For comparison, casting was performed in the same manner without the above addition. It was confirmed that the addition of ZrC particles improved the hardness, wear resistance, and tensile strength.
[0068]
By atomizing the molten alloy to which the ZrC particles are added, a ZrC particle-containing metal matrix composite material powder can be produced.
Since ZrC particles do not dissolve in the molten Al alloy, it is also possible to obtain a metal matrix composite material with higher strength by increasing the amount of ZrC particles added.
Example 5
According to the third aspect of the first invention, a metal matrix composite material in which HfC particles were produced in pure aluminum was produced by the following procedure.
[0069]
[Production of molded body]
Pure aluminum powder (−45 μm, 99.99%), pure hafnium powder (−45 μm, 98%), and pure graphite powder (−45 μm, 99%) were weighed and mixed, respectively, 7 g, 31.73 g and 2.14 g. , Molding pressure 7t / cm²A cylindrical shaped body with a diameter of 30 mm was prepared. The porosity of the obtained molded body was about 6%.
[0070]
At this time, it is desirable that the mixing ratio of the Hf powder and the C powder corresponds to the stoichiometric ratio (molar ratio) of HfC. The mixing ratio of Hf powder and C powder to Al powder is not particularly limited. The mixing ratio of the powder can be adjusted according to the target HfC concentration of the HfC particle-containing molded body to be finally produced.
[Impregnation of molten aluminum]
The molded body was immersed in a pure aluminum melt (purity 99.99%) at 730 ° C. for 30 seconds, and then quickly removed from the molten metal, and the voids of the molded body were impregnated with the pure aluminum melt. By this impregnation, the weight of the molded body increased from 40.87 g before impregnation to about 65 g.
[0071]
[Generation of HfC particles]
Rapid heating for generating HfC particles was performed by high-frequency induction heating using the same vacuum melting furnace as in Example 1. However, for the purpose of comparison, heating with a normal electric furnace was also performed. The produced particles were subjected to phase identification by X-ray diffraction and particle size measurement by image analysis of SEM microstructure photographs. Table 5 shows the heating conditions and the product phase.
[0072]
[Table 5]

[0073]
The generation of HfC particles is due to the following reactions occurring in order from the low temperature side in a temperature range of about 650 ° C. or higher.
Hf + 3Al → HfAl_Three      (1)
HfAl_Three+ C → HfC + 3Al (2)
When the powder compact is impregnated with molten Al, the Hf powder particles react with the molten Al (1), and fine HfAl is formed around the Hf powder particles._ThreeParticles are generated. When the next rapid heating is performed in this state, the reaction (2) is promoted.
[0074]
In order to produce HfC by reaction (2), it is usually necessary to heat to a high temperature range of 1000 ° C. or higher. By heating rapidly to a temperature of about 650 ° C. where reaction (1) takes place by rapid heating at a rate of temperature increase of 20 ° C./min or more according to the present invention, the temperature automatically rises due to self-heating by reaction (1). ) Occurs and HfC is generated. The required heating time was 20 seconds to 2 minutes.
[0075]
In this example, an inert gas atmosphere was used as the heating atmosphere, but even if heated in the atmosphere, there is no problem because the surface of the molded body is only slightly oxidized if the rapid heating of the present invention is used. .
[Addition to molten metal]
In accordance with the third aspect of the second invention, the HfC particle-containing molded body produced according to Invention Example 1 was added to a molten Al-Si alloy (AC8A) maintained at 800 ° C. (weight: 500 g) (addition amount: 45 g). After stirring for 5 minutes, it was cast into a JIS No. 4 boat mold preheated to 80 ° C. at a molten metal temperature of 750 ° C. For comparison, casting was performed in the same manner without the above addition. It was confirmed that the addition of HfC particles improved the hardness, wear resistance, and tensile strength.
[0076]
By atomizing the molten alloy to which the HfC particles are added, the HfC particle-containing metal matrix composite material powder can be produced.
Since HfC particles do not dissolve in the molten Al alloy, it is also possible to obtain a metal matrix composite material with higher strength by increasing the amount of HfC particles added.
Example 6
In accordance with the fourth aspect of the first invention, a metal matrix composite material in which NbC particles were produced in pure aluminum was produced by the following procedure.
[0077]
[Production of molded body]
Pure aluminum powder (−45 μm, 99.99%), pure niobium powder (−150 μm, 99.9%), and pure graphite powder (−45 μm, 99%) were weighed 7 g, 19.49 g, and 2.52 g, respectively. Mix, forming pressure 7t / cm²A cylindrical shaped body with a diameter of 30 mm was prepared. The porosity of the obtained molded body was about 10%.
[0078]
At this time, it is desirable that the mixing ratio of the Nb powder and the graphite powder corresponds to the stoichiometric ratio (molar ratio) of NbC. The mixing ratio of Nb powder, graphite powder and Al powder is not particularly limited. The mixing ratio of the powder can be adjusted according to the target NbC concentration of the NbC particle-containing molded body to be finally produced.
[Impregnation of molten aluminum]
The molded body was immersed in a pure aluminum melt (purity 99.99%) at 730 ° C. for 30 seconds, and then quickly removed from the molten metal, and the voids of the molded body were impregnated with the pure aluminum melt. This impregnation increased the weight of the compact from 29.01 g before impregnation to about 35 g.
[0079]
[Generation of NbC particles]
Rapid heating for generating NbC particles was performed by high frequency induction heating using the same vacuum melting furnace as in Example 1. However, for the purpose of comparison, heating with a normal electric furnace was also performed. The produced particles were subjected to phase identification by X-ray diffraction and particle size measurement by image analysis of SEM microstructure photographs. Table 6 shows the heating conditions and the product phase.
[0080]
[Table 6]

[0081]
NbC particles are produced by the following reactions in order from the low temperature side in a temperature range of about 650 ° C. or higher.
Nb + 3Al → NbAl_Three      (1)
NbAl_Three+ C → NbC + 3Al (2)
When the powder compact is impregnated with molten Al, Nb powder particles and Al molten metal react as described in (1) above, and fine NbAl is formed around the Nb powder particles._ThreeParticles are generated. When the next rapid heating is performed in this state, the reaction (2) is promoted.
[0082]
In order to produce NbC by reaction (2), it is usually necessary to heat to a high temperature range of 1000 ° C. or higher. By heating rapidly to a temperature of about 650 ° C. where reaction (1) takes place by rapid heating at a rate of temperature increase of 20 ° C./min or more according to the present invention, the temperature automatically rises due to self-heating by reaction (1). ) Occurs and NbC is generated. The required heating time was 20 seconds to 2 minutes.
[0083]
In this example, an inert gas atmosphere was used as the heating atmosphere, but even if heated in the atmosphere, there is no problem because the surface of the molded body is only slightly oxidized if the rapid heating of the present invention is used. .
[Addition to molten metal]
In accordance with the fourth aspect of the second invention, the NbC particle-containing compact produced according to Invention Example 1 was added to a molten Al-Si alloy (AC8A) maintained at 800 ° C. (weight: 500 g) (addition amount: 35 g). After stirring for 5 minutes, it was cast into a JIS No. 4 boat mold preheated to 80 ° C. at a molten metal temperature of 750 ° C. For comparison, casting was performed in the same manner without the above addition. It was confirmed that the addition of NbC particles improved the hardness, wear resistance, and tensile strength.
[0084]
By atomizing the molten alloy to which the NbC particles are added, the NbC particle-containing metal matrix composite material powder can be produced.
Since NbC particles do not dissolve in the Al alloy melt, it is also possible to obtain a metal matrix composite material with higher strength by increasing the amount of NbC particles added.
Example 7
In accordance with the fifth aspect of the first invention, TiB in pure aluminum₂The metal matrix composite material in which the particles were produced was produced by the following procedure.
[0085]
[Production of molded body]
Pure aluminum powder (−45 μm, 99.99%), pure titanium powder (−150 μm, 99.4%), AlB₂Powder (−45 μm, 99%) is mixed at a weight ratio of 5: 8: 8, and molding pressure is 7 t / cm.²A cylindrical shaped body of φ30 × 10 mm was prepared. The porosity of the obtained molded body was about 10%.
[0086]
At this time, Ti powder and AlB₂Mixing ratio with powder is TiB₂It is desirable to correspond to the stoichiometric ratio (molar ratio). Ti powder and AlB₂The mixing ratio of the powder and the Al powder is not particularly limited. The final mixing ratio of powder is TiB₂Target TiB of particle-containing compact₂It can be adjusted according to the concentration.
[Impregnation of molten aluminum]
The molded body was immersed in a pure aluminum melt (purity 99.99%) at 730 ° C. for 30 seconds, and then quickly removed from the molten metal, and the voids of the molded body were impregnated with the pure aluminum melt. By this impregnation, the weight of the molded body was increased from 24.87 g before impregnation to about 35 g.
[0087]
[TiB₂Particle generation)
TiB₂Rapid heating for particle generation was performed by high frequency induction heating using the same vacuum melting furnace as in Example 1. However, for the purpose of comparison, heating with a normal electric furnace was also performed. The produced particles were subjected to phase identification by X-ray diffraction and particle size measurement by image analysis of SEM microstructure photographs. Table 7 shows the heating conditions and the product phase.
[0088]
[Table 7]

[0089]
TiB₂The generation of particles is due to the following reactions occurring in order from the low temperature side in a temperature range of 617 ° C. or higher.
Ti + 3Al → TiAl_Three          (1)
TiAl_Three+ AlB₂→ TiB₂+ 3Al (2)
AlB₂+ T → Al + TiB₂        (3)
When the powder compact is impregnated with molten Al, Ti powder particles and Al molten metal react as described in (1) above, and fine TiAl is formed around the Ti powder particles._ThreeParticles are generated. When the next rapid heating is performed in this state, the reaction (2) is promoted.
[0090]
TiB by reaction (2) and (3)₂For production, it is usually necessary to heat to a high temperature range of 1000 ° C. or higher. When heated to 617 ° C. where reaction (1) takes place by rapid heating at a heating rate of 20 ° C./min or more according to the present invention, the temperature automatically rises due to self-heating by reaction (1) and reaction (2) And (3) happen and TiB₂Produces. The heating time for production was 20 seconds to 2 minutes.
[0091]
In Table 7, Invention Example 1 was heated to 700 ° C. at 20 ° C./min after high-temperature heating after impregnation with molten aluminum. The temperature was automatically raised to 1350 ° C. and then the temperature dropped rapidly. The time required from 700 ° C. to 1350 ° C. was about 20 seconds. The sample after heating was TiB with an average particle size of 0.2 μm (maximum particle size of 3 μm) in an Al matrix.₂The particles were uniformly dispersed.
[0092]
Comparative Example 1 was heated to 20O <0> C / min to 600 [deg.] C. by high-frequency heating after impregnation with molten aluminum, and since it did not reach the temperature of reaction (1), self-heating did not occur. The sample after heating is TiB₂Is not produced, Al, Ti, AlB of raw material powder₂Al produced during impregnation_ThreeTi was mixed.
Comparative Example 2 was heated to 1100 ° C. at 10 ° C./min after impregnation with molten aluminum, and after reaching 1100 ° C., the power of the furnace was turned off and the furnace was cooled to room temperature. The sample after heating was TiB with an average particle size of 0.5 μm (maximum particle size of 3 μm) in an Al matrix.₂The particles were uniformly dispersed, but unreacted AlB₂And Ti remained.
[0093]
Comparative Example 3 was heated in an electric furnace in the same manner as Comparative Example 2 without impregnating the molten aluminum. However, the heating atmosphere was in the air. The sample after heating was TiB having an average particle size of 3 μm (maximum particle size of 10 μm) in a porous Al matrix.₂The particles were dispersed. In addition, Al on the sample surface₂O_ThreeEtc. were generated.
[Addition to molten metal]
TiB produced according to Invention Example 1 according to the fifth aspect of the second invention₂Particle-containing compact (TiB₂Concentration: about 33 vol% (45 wt%)) was added to each of the molten Al-4.5Cu alloy and Al-Si alloy (AC8A) held at 800 ° C. (weight: 500 g) (TiB₂(Addition amount: 0.05 to 5 vol%) After stirring for 5 minutes, a molten metal temperature of 750 ° C. was cast into a JIS No. 4 boat mold preheated to 80 ° C. For comparison, casting was performed in the same manner without the above addition.
[0094]
TiB₂It was confirmed that the macrostructure of the cast material was remarkably refined by the addition of. This refinement effect was equivalent for the addition amount in the above range. The average grain size of the Al-4.5Cu alloy was about 3 mm with no additive, but TiB₂The additive was refined to 30 μm, and the shape of the crystal grains was all changed from a dendrite structure to an equiaxed crystal. In the AC8A alloy, a dendrite structure remains and the crystal grain size cannot be measured quantitatively. However, as shown in FIG.₂It turns out that it refines remarkably by addition.
[0095]
Table 8 shows the mechanical properties. Invention Examples 2 to 7 and Comparative Examples 4 and 5 are cast materials produced by the above casting. Invention Examples 8 and 9 are the above TiB₂It is a powder metallurgical material produced by hot extrusion from powder obtained by atomizing the molten metal under the following conditions. The tensile strength characteristics and the wear resistance characteristics were evaluated by the same test as in Example 3.
<Atomization conditions>
Molten metal temperature: 1100 ° C
Spray pressure: 9.8 MPa (N₂gas)
Spray nozzle diameter: φ2mm
<Hot extrusion conditions>
Put 30g of atomized powder in a copper can of φ30mm, 3ton / cm²A preform was prepared at a pressure of 1 mm, and this was heated in a nitrogen gas atmosphere for 1 hour for deaeration, and then indirect extrusion was performed.
[0096]
Temperature: 400 ° C
Extrusion ratio: 12
Ram speed: 0.2mm / sec
[0097]
[Table 8]

[0098]
From the results of Table 8, it can be seen that in all cast materials, TiB₂It can be seen that the strength and ductility are greatly improved by the addition. As described above, the present invention provides a remarkable effect that the strength and ductility can be improved at the same time by refining the structure and strengthening the dispersion.
It can be seen that the powder metallurgy material can achieve both high strength and ductility. In this example, only the evaluation with the same composition as the cast material was performed.₂Since the particles do not dissolve in the Al alloy melt, TiB₂By increasing the amount of particles added, it is also possible to obtain a metal matrix composite material with higher strength.
[0099]
In each of the above embodiments, TiC, ZrC, HfC, NbC, or TiB in the Al or Al alloy matrix.₂The case of producing an Al-based composite material in which particles are dispersed will be described. However, the present invention is not limited to this, and when heated rapidly, the compound formation reaction self-heats until the final compound particle formation reaction. Of course, the present invention can be applied to any matrix composition and compound composition that can proceed automatically.
[0100]
【The invention's effect】
As described above, according to the present invention, the method for producing a dispersion-strengthening compound particle by impregnating a powder molded body with a molten metal is improved, and it is extremely short without requiring high temperature and long time heating. In this process, the size of the molded body that can be processed at one time can be increased, and a metal matrix composite can be manufactured with high productivity.
[Brief description of the drawings]
FIG. 1 shows differential heat showing an exothermic peak and an endothermic peak generated in a process of slowly raising temperature from room temperature for a sample in which Al is impregnated with a green compact made of Ti powder, graphite powder, and Al powder. It is an analysis (DTA) chart. The horizontal axis represents temperature, and the vertical axis represents the temperature difference ΔT with respect to a standard sample (a substance having no exothermic or endothermic reaction in the measurement temperature range).
FIG. 2 is a graph schematically showing an exothermic peak when a series of reactions apparently and continuously proceed due to self-heating during rapid heating according to the present invention, in contrast to the DTA curve of FIG. It is. However, the horizontal axis is time.
FIG. 3 is a metallographic photograph showing an example of the microstructure of a molded article after impregnation. Fine TiAl of about 1 μm around Ti particles (white) dispersed in an Al matrix (black)_ThreeMany (gray) are generated.
FIG. 4 is a graph showing the relationship between the hardness of pure Mg and AZ91 alloy and the amount of TiC particles added.
FIG. 5 is a graph showing the relationship between the wear depth of pure Mg and AZ91 alloy and the amount of TiC particles added.
FIG. 6 is a graph showing the relationship between the tensile strength of pure Mg and AZ91 alloy and the addition amount of TiC particles.
FIG. 7 is a graph showing the relationship between the elongation of pure Mg and AZ91 alloy and the amount of TiC particles added.
FIG. 8 is a metallographic photograph showing a macrostructure of a pure Mg cast material with and without TiC particle addition (A) and (B).
FIG. 9 shows TiB₂It is a metal structure photograph which shows the macro structure of AC8C alloy cast material with and without particle addition (A) and (B).

Claims (13)

In a method for producing a metal matrix composite material in which compound particles of a first element and a second element are dispersed in a metal matrix made of a metal or a metal alloy, the following steps are performed:
Forming a molded body comprising the powder of the first element, the powder of the second element or the compound of the second element, and the powder of the metal or metal alloy;
A step of impregnating a molten metal or metal alloy in the molded body, and rapid heating of the entire impregnated molded body in an inert atmosphere in the molded body. A step of causing a compounding reaction between one element and the metal, and automatically raising the temperature of the compact by heat generated by the compounding reaction to generate a reaction for generating the compound particles in the compact, The heating rate of the rapid heating is such that the entire molded body is made of the compound by the residual heat obtained by subtracting the heat loss from the heat generated by the combination reaction of the first element and the metal to the outside and the endothermic reaction that can occur. A heating rate at which the combination reaction of the first element and the metal proceeds in a sufficiently short time so that the temperature can be automatically raised to the temperature at which the particle formation reaction occurs. Compound of the first element and the metal Step in the range of up to an upper limit temperature at which the can occur in the lower limit temperature may occur in production reaction of the compound particles,
A method for producing a metal matrix composite material, comprising: A molded body containing the compound particles produced by the method according to claim 1 is introduced into a molten metal or metal alloy, and a metal matrix of the molded body is dissolved in the molten metal, and the compound particles are dissolved in the molten metal. A method for producing a metal matrix composite material, characterized in that the molten metal is solidified after being dispersed in the metal. The method according to claim 1, wherein the compound particles made of TiC are dispersed in the metal matrix made of Al or an Al alloy, wherein the first element is Ti, A method for producing a metal matrix composite material, wherein the second element is C, and a formed body comprising Ti powder, C powder, and Al or Al alloy powder is formed in the step of forming the formed body. 4. The method for producing a metal matrix composite material according to claim 3, wherein SiC powder is used in place of the C powder in the step of forming the molded body. The method according to claim 1, wherein the compound particles made of ZrC are dispersed in the metal matrix made of Al or an alloy of Al, wherein the first element is Zr, A method for producing a metal matrix composite material, wherein the second element is C, and in the step of forming the formed body, a formed body comprising Zr powder, C powder, and Al or Al alloy powder is formed. The method according to claim 1, wherein the compound particles made of HfC are dispersed in the metal matrix made of Al or an alloy of Al, wherein the first element is Hf, A method for producing a metal matrix composite material, wherein the second element is C, and in the step of forming the formed body, a formed body comprising Hf powder, C powder, and Al or Al alloy powder is formed. The method according to claim 1, wherein the compound particles made of NbC are dispersed in the metal matrix made of Al or an Al alloy, wherein the first element is Nb, A method for producing a metal matrix composite material, wherein the second element is C, and in the step of forming the formed body, a formed body comprising Nb powder, C powder, and Al or Al alloy powder is formed. The method according to claim 1, wherein the compound particles made of TiB ₂ are dispersed in the metal matrix made of Al or an Al alloy, wherein the first element is Ti, A metal-based composite material, wherein the second element is B, and a formed body comprising Ti powder, AlB ₂ or AlB ₁₂ powder, and Al or Al alloy powder is formed in the step of forming the formed body. Production method. In the method for producing a metal matrix composite in which TiC particles are dispersed in a metal matrix made of Al or an Al alloy, the following steps are performed:
Forming a molded body composed of Ti powder, C powder and Al or Al alloy powder;
A step of impregnating the molten body of Al or Al alloy in the molded body, and a rapid heating of the entire impregnated molded body in an inert atmosphere to bring the Al or Al alloy close to the melting point in the molded body. causing TiAl ₃ generation reaction occurring in, a process to produce a TiC particle formation reaction in the molded article automatically by rapidly heating the shaped article by heating of the TiAl ₃ formation reaction, the sudden speed heating The heating rate is automatically reduced to the temperature at which the entire formed body reaches the TiC particle formation reaction due to the heat generated in the TiAl ₃ formation reaction and the remaining heat minus the heat loss due to the endothermic reaction that can occur. The heating rate is such that the TiAl ₃ production reaction proceeds in a sufficiently short time so that the temperature can be increased, and the temperature reached by the rapid heating is lower than the lower limit temperature at which the TiAl ₃ production reaction can occur. a step within a range up to an upper limit temperature at which iC particle generation reaction can occur,
A method for producing a metal matrix composite material, comprising: From the lower limit temperature 617 ° C. at which the reaction temperature of the rapid heating can reach a TiAl ₃ formation reaction due to the combination of solid Al and solid Ti, an upper limit at which a solid TiC particle formation reaction due to the reaction between solid TiAl ₃ and solid C can occur The method for producing a metal matrix composite material according to claim 9, wherein the temperature is within a range up to 992 ° C. The method for producing a metal matrix composite material according to any one of claims 3 to 10, wherein a heating rate of the rapid heating is 20 ° C / min or more. The method for producing a metal matrix composite material according to any one of claims 3 to 11, wherein the rapid heating is performed by induction heating. The molded body containing any one of TiC particles, ZrC particles, HfC particles, NbC particles, and TiB ₂ particles produced by the method according to any one of claims 3 to 12, is made of Al, Al alloy, Mg, or A metal matrix composite material, wherein the metal matrix composite material is introduced into a molten Mg alloy, the metal matrix of the compact is dissolved in the molten metal, and the particles are dispersed in the molten metal, and then the molten metal is solidified. Production method.

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