JP3871805B2 - Method for producing Al-based composite member - Google Patents

Description

【００３５】
図１０は表１をグラフ化したものである。図１０から、実施例による試験片は比較例による試験片に比べて常温および高温における疲労強度が高く、バルブスプリングリテーナ１に要求される常温疲労強度２２０ＭＰａ以上および高温（２００℃）疲労強度１９０ＭＰａ以上の両要件をそれぞれ満足していることが明らかである。
【００３６】
通常、前記Ａｌ合金マトリックスにＡｌ₂ Ｏ₃ 粒子を分散させると、その部材の疲労強度はＡｌ合金マトリックスのそれよりも低くなる傾向があるが、実施例による試験片においては、Ａｌ₂ Ｏ₃ 粒子の均一分散による複合効果が発現しているので、前記のような好結果が得られるのである。
【００３７】
また原料粉末の調製に当り、従来のブレード回転型混合機を用いた、ということ以外は前記実施例と同様の方法を行って他の比較例による試験片を製造した。実施例による試験片および他の比較例による試験片について、引張強さ、耐力、シャルピー衝撃値および伸びについて測定を行ったところ、表２の結果を得た。
【００３８】
【表２】

【００３９】
表２から明らかなように、実施例１による試験片は、他の比較例による試験片に比べて優れた強度および靱延性を有する。これは次のような理由による。即ち、実施例による試験片においてはＡｌ₂ Ｏ₃ 粒子が均一に分散すると共にそのＡｌ₂ Ｏ₃ 粒子とＡｌ合金マトリックスとが緊密に接触しているが、他の比較例による試験片においてはＡｌ₂ Ｏ₃ 粒子の凝集体が存在して、その内部にＡｌ合金が未充填の微小空隙が発生し、これが欠陥として作用しているからである。
【００４０】
また両試験片について、次のような条件で摩耗試験を行った。試験条件は次の通りである。すべり速度：２ｍ／sec ；荷重：約４９Ｎ；潤滑剤：エンジンオイル；潤滑剤供給量：１０cc／min ；相手材：鋳鉄ディスク．
実施例による試験片の摩耗量は０．０１mm³ であったが、他の比較例による試験片の摩耗量は２．４mm³ であって、この値は前記Ａｌ合金マトリックスのみからなる試験片の摩耗量と略同じであった。このように摩耗量が多いのは、Ａｌ₂ Ｏ₃ 粒子の不均一分散および前記凝集体の存在に起因する。
【００４１】
前記製造方法は内燃機関用バルブリフタ等の製造にも適用される。
【００４２】
【発明の効果】
本発明によれば、前記のような手段を採用することによって、優れた機械的特性を有するＡｌ基複合部材を量産することが可能な製造方法を提供することができる。
【図面の簡単な説明】
【図１】 バルブスプリングリテーナの断面図である。
【図２】 自転公転型混合機の概略斜視図である。
【図３】 ビレットの斜視図である。
【図４】 押出し機の断面図である。
【図５】 多孔ダイスの正面図である。
【図６】 押出し材から素材を切出す状態を示す説明図である。
【図７】 バルブスプリングリテーナの斜視図である。
【図８】 試験温度と疲労強度との関係を示すグラフである。
【符号の説明】
１………バルブスプリングリテーナ（Ａｌ基複合部材）
２………自転公転型混合機
２ａ……容器
３………自転軸
４………公転軸
５………ビレット
９………多孔ダイス
１３……押出し材
１４……素材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an Al-based composite member, in particular, preparation of a raw material powder composed of rapidly solidified Al alloy powder and hard particles, extrusion using a billet composed of the raw material powder, and a material cut out from the extruded material. The present invention relates to a method for obtaining an Al-based composite member by sequentially performing the forging used.
[0002]
[Prior art]
Conventionally, a high-energy blade rotating mixer is generally used for preparing the raw material powder. In addition, a die having one die hole is usually used for the extrusion process, and the forging process is usually performed hot.
[0003]
[Problems to be solved by the invention]
However, according to the conventional blade rotating type mixer, due to its high energy, granulation occurs before uniform mixing of rapidly solidified Al alloy powder and hard particles occurs. Aggregates with a large amount of hard particles exist. If the diameter of the agglomerates exceeds about 200 μm and the amount of agglomerates in the mixed powder exceeds 6 per 1 kg of the mixed powder, it will adversely affect the normal temperature and high temperature fatigue strength, toughness, etc. of the Al-based composite member. There was a problem.
[0004]
Also, according to the conventional extrusion method, when the cross-sectional dimension of the extruded material is extremely small with respect to the billet diameter, that is, when the extrusion ratio is too large, the extrusion surface pressure reaches the limit and the extrusion is performed smoothly. There was a problem that the billet temperature was lowered because it was not broken, and clogging occurred due to these.
[0005]
Furthermore, according to the conventional hot forging method, since the heating temperature of the material, that is, the forging temperature is set to a relatively high value such as 450 to 550 ° C., the material characteristics of the Al alloy matrix are easily deteriorated, and the die There was a problem that the durability was lost due to thermal degradation of the steel.
[0006]
[Means for Solving the Problems]
An object of the present invention is to provide a method for producing the Al-based composite member capable of solving various problems related to preparation of raw material powder, extrusion processing, and forging processing in conventional methods.
[0007]
In order to achieve the above object, according to the present invention, a revolution / revolution type mixer configured to rotate around a predetermined revolution axis at the same time as the container rotates around a predetermined revolution axis. A step of preparing a raw material powder composed of rapidly solidified Al alloy powder and hard particles placed in the container, a step of extruding with a porous die using a billet composed of the raw material powder, The manufacturing method of the Al group composite member characterized by including the process of warm-forging using the raw material cut out from the material, and a sealing metal mold | die is provided.
[0008]
When the raw material powder is prepared with a rotating and revolving mixer with lower energy compared to the blade rotating mixer, it avoids the occurrence of granulation phenomenon due to local energy concentration, and there is no dead zone in the machine. Thus, uniform mixing appears, which makes it possible to sufficiently disperse the hard particles.
[0009]
In addition, since a porous die is used in the extrusion process, even when the extrusion ratio is too large, it is possible to perform smooth extrusion by lowering the extrusion surface pressure, thereby avoiding clogging.
[0010]
Further, since the warm forging method is employed in the forging process, the forging temperature is relatively low, thereby avoiding the deterioration of the material characteristics of the Al alloy matrix and extending the life of the sealed mold. In addition, the yield is good due to the use of a closed mold.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a valve spring retainer 1 for an internal combustion engine as an Al-based composite member, and the valve spring retainer 1 is composed of an Al alloy matrix and hard particles uniformly dispersed therein.
[0012]
In manufacturing the valve spring retainer 1, a process of preparing a raw material powder composed of rapidly solidified Al alloy powder and hard particles using a rotating and rotating mixer with lower energy than a conventional blade rotating mixer. And the process of performing the extrusion process by a porous die using the billet which consists of raw material powder, and the process of performing the warm forging using the raw material and sealing mold which were cut out from the extrusion material are used.
[0013]
As shown in FIG. 2, the low-energy rotating / revolving mixer 2 is in a crossing relationship with the rotating shaft 3 at the same time as the container 2 a containing the rapidly solidified Al alloy powder and the hard particles rotates around the rotating shaft 3. The rotating shaft 4 is also configured to rotate. Thus, when the raw material powder is prepared by the low energy rotation and revolution type mixer 1, the occurrence of granulation phenomenon due to local energy concentration is avoided, and there is no dead zone in the machine, Uniform mixing appears, which makes it possible to sufficiently disperse the hard particles.
[0014]
In the extrusion process, the following means are employed. (1) As shown in FIG. 3, the short cylindrical billet 5 is manufactured by performing CIP using raw material powder. (2) The billet 5 is heated to the extrusion temperature. (3) As shown in FIG. 4, the billet 5 is charged into the heated container 7 of the extruder 6. In this case, the dummy block 8 and the porous die 9 are heated, respectively, while the ram 10 and the die stem 11 are not heated. As clearly shown in FIG. 5, the porous die 9 has six die holes 12 arranged in the circumferential direction. (4) In a state where the porous die 9 is fixed by the die stem 11, the container 7, billet 5 and dummy block 8 are moved by the ram 10 in the direction of the arrow in FIG.
[0015]
Thus, when the porous die 9 is used in the extrusion process, even when the extrusion ratio is too large, it is possible to reduce the extrusion surface pressure and perform smooth extrusion, thereby avoiding the occurrence of clogging.
[0016]
In this case, in order to prevent the occurrence of the initial clogging, it is an effective means to set the temperature of the porous die 9 relatively high and correct the temperature drop to reduce the initial extrusion load. In addition, it is an effective means to keep the billet 5 warm by the dummy block 8 in order to prevent the occurrence of clogging on the way.
[0017]
In the warm forging process, as shown in FIG. 6, the material 14 is cut out from the extruded material 13, and then the material 14 is lubricated, and then forged at a forging temperature of 250 to 300 ° C. using a sealed mold. The valve spring retainer 1 shown in FIG. 7 is obtained.
[0018]
By adopting the warm forging method in this way, it is possible to set the forging temperature relatively low to avoid deterioration of the material properties of the Al alloy matrix and to prolong the life of the sealed mold. In addition, the yield is good due to the use of a closed mold.
[0019]
The rapidly solidified Al alloy powder, and hence the Al alloy matrix, is composed of 4 atomic% ≦ TM ≦ 7 atomic%, 0.5 atomic% ≦ X ≦ 3 atomic%, 1 atomic% ≦ Si ≦ 3 atomic%, and the balance Al. Is at least one selected from Fe and Ni, and X is at least one selected from Ti, Zr, Mg and rare earth elements.
[0020]
The hard particles are Al ₂ O ₃ particles, the average particle diameter D ₃ is 1.5 μm ≦ D ₃ ≦ 10 μm, and the volume fraction Vf is set to 0.5% ≦ Vf ≦ 20%. The
[0021]
If the content of each alloy element is specified as described above, this composition has a high amorphous phase forming ability, so that the metal structure of the Al alloy matrix becomes uniform and fine, which makes the Al alloy matrix excellent. It has heat resistance and toughness and high fatigue strength at high temperatures.
[0022]
In alloy elements, TM such as Fe contributes to improvement in heat resistance strength. However, when the TM content is TM <4 atomic%, the heat resistance strength is low, whereas when TM> 7 atomic%, the toughness and ductility is significantly reduced.
[0023]
X and Si such as Ti contribute to the improvement of the amorphous phase forming ability. However, if the Si content is Si <1 atomic% or Si> 3 atomic%, the ability to form an amorphous phase is lowered, so that toughness and fatigue strength at high temperatures are lowered.
[0024]
When the TM content is 4 atomic% ≦ TM ≦ 7 atomic% and the Si content is 1 atomic% ≦ Si ≦ 3 atomic%, 2.3 ≦ TM / between the TM content and the X content. By establishing the relationship X ≦ 8, it is possible to construct an Al alloy matrix having excellent characteristics as described above. Therefore, the X content is set to 0.5 atomic% ≦ X ≦ 3 atomic%. Is done.
[0025]
In this case, the average particle diameter D ₁ of the Al crystals constituting the matrix is D ₁ ≦ 1 μm, and the average particle diameter D ₂ of the intermetallic compound is D ₂ ≦ 0.5 μm. However, if the average particle diameter D ₁ of the Al crystal is D ₁ > 1 μm, or the average particle diameter D ₂ of the intermetallic compound is D ₂ > 0.5 μm, the heat resistance or the heat resistance and fatigue under high temperature Strength decreases.
[0026]
When the average particle diameter D ₃ of Al ₂ O ₃ particles and the volume fraction Vf thereof are specified as described above, the characteristics of the Al alloy matrix are further improved due to the uniform dispersion of Al ₂ O ₃ particles. A valve spring retainer 1 having excellent wear resistance can be obtained. However, when the average particle diameter D ₃ of Al ₂ O ₃ particles is D ₃ <1.5 μm, the above effect cannot be obtained. On the other hand, when D ₃ > 10 μm, the fatigue strength at high temperature decreases and the wear amount of the mating member decreases. To increase. Further, when the volume fraction Vf of Al ₂ O ₃ particles is Vf <0.5%, the above effect cannot be obtained. On the other hand, when Vf> 20%, the fatigue strength at high temperature is lowered and the wear amount of the mating member is increased. .
[0027]
Usually, the upper limit of the volume fraction Vf of hard particles such as Al ₂ O ₃ particles in the Al-based composite member is about 10% in consideration of the dispersibility. Since the uniform dispersion of particles can be achieved, the upper limit of the volume fraction Vf can be increased approximately twice.
[0028]
Hereinafter, the production of the valve spring retainer 1 will be specifically described.
[0029]
I. Preparation of raw powder (Figure 2)
A molten metal having an Al ₉₁ Fe ₆ Ti ₁ Si ₂ alloy composition (the unit of numerical values is atomic%) is prepared, and then rapidly solidified Al alloy powder is manufactured under the application of an air atomization method using this molten metal. Classification was performed to obtain a powder having a particle size of 75 μm or less.
[0030]
Al ₂ O ₃ particles having an average particle diameter D ₃ of D ₃ = 3 μm are added to rapidly solidified Al alloy powder (particle diameter of 75 μm or less) so that the volume fraction Vf is 5%, and then these are added. The raw material powder was prepared under the following conditions by putting it into the low energy rotation / revolution mixer 2. That is, rotation speed: rotation 30 rpm, revolution 15 rpm; capacity: 20 kg / batch; atmosphere: argon gas; dispersion medium: 5 kg of alumina balls (or zirconia balls) having a diameter of 10 mm; mixing time: 3 hours.
II. Extrusion processing (Figures 3-5)
Billet 5 having a diameter of about 150 mm and a length of about 300 mm was manufactured by performing CIP using the raw material powder under a pressure of 180 MPa.
[0031]
Using this billet 5, extrusion processing was performed under the conditions of an extrusion ratio of 11, an extrusion temperature of 475 ° C., a container temperature of 450 ° C., a porous die temperature of 530 ° C., and a dummy block temperature of 530 ° C. Obtained.
[0032]
III. Forging (Figs. 6 and 7)
The raw material 14 was cut out from the extruded material 13, and then the raw material 14 was lubricated using MoS ₂ , and then warm forging was performed at a forging temperature of 270 ° C. using a hermetically sealed mold to obtain the valve spring retainer 1.
[0033]
About a test piece (Example) corresponding to the valve spring retainer 1 and a test piece (Comparative Example) corresponding to a valve spring retainer obtained by warm forging using only the rapidly solidified Al alloy powder, When a rotating bending fatigue test was performed in a temperature range from room temperature to 300 ° C. (high temperature), the results shown in Table 1 were obtained.
[0034]
[Table 1]

[0035]
FIG. 10 is a graph of Table 1. From FIG. 10, the test piece according to the example has higher fatigue strength at normal temperature and high temperature than the test piece according to the comparative example, and normal temperature fatigue strength of 220 MPa or higher and high temperature (200 ° C.) fatigue strength of 190 MPa or higher required for the valve spring retainer 1. It is clear that both requirements are satisfied.
[0036]
Usually, the dispersing Al ₂ O ₃ particles in the Al alloy matrix, the fatigue strength of the member tends to be lower than that of the Al alloy matrix, in the test piece according to Example, Al ₂ O ₃ particles Since the composite effect due to the uniform dispersion is expressed, the above-mentioned good results can be obtained.
[0037]
Further, in preparing the raw material powder, a test piece according to another comparative example was manufactured in the same manner as in the above example except that a conventional blade rotating mixer was used. About the test piece by an Example and the test piece by another comparative example, when the tensile strength, yield strength, Charpy impact value, and elongation were measured, the result of Table 2 was obtained.
[0038]
[Table 2]

[0039]
As is clear from Table 2, the test piece according to Example 1 has superior strength and toughness as compared with the test pieces according to other comparative examples. This is due to the following reason. That is, in the test pieces according to the examples, Al ₂ O ₃ particles are uniformly dispersed and the Al ₂ O ₃ particles and the Al alloy matrix are in intimate contact, but in the test pieces according to other comparative examples, Al ₂ O ₃ particles are in close contact. _This is because there are agglomerates of ₂ O ₃ particles, and microvoids that are not filled with an Al alloy are generated therein, which act as defects.
[0040]
Moreover, the abrasion test was done about both test pieces on the following conditions. The test conditions are as follows. Sliding speed: 2 m / sec; Load: about 49 N; Lubricant: Engine oil; Lubricant supply amount: 10 cc / min;
The wear amount of the test piece according to the example was 0.01 mm ³ , but the wear amount of the test piece according to another comparative example was 2.4 mm ³ , which is the value of the test piece made of only the Al alloy matrix. It was almost the same as the amount of wear. The large amount of wear is caused by the non-uniform dispersion of Al ₂ O ₃ particles and the presence of the agglomerates.
[0041]
The manufacturing method is also applied to the manufacture of valve lifters for internal combustion engines.
[0042]
【The invention's effect】
According to the present invention, it is possible to provide a manufacturing method capable of mass-producing an Al-based composite member having excellent mechanical characteristics by employing the above-described means.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a valve spring retainer.
FIG. 2 is a schematic perspective view of a rotation and revolution type mixer.
FIG. 3 is a perspective view of a billet.
FIG. 4 is a cross-sectional view of an extruder.
FIG. 5 is a front view of a porous die.
FIG. 6 is an explanatory view showing a state in which a material is cut out from an extruded material.
FIG. 7 is a perspective view of a valve spring retainer.
FIG. 8 is a graph showing the relationship between test temperature and fatigue strength.
[Explanation of symbols]
1 ……… Valve spring retainer (Al-based composite member)
2 ... Rotating and revolving mixer
2a …… Container
3 ……… Rotation axis
4 ... Revolution shaft 5 ... Billet 9 ... Perforated die 13 ... Extruded material 14 ... Material

Claims (4)

A rotation / revolution mixer configured such that the container (2a) rotates around a predetermined rotation axis (3) and simultaneously rotates around a predetermined revolution axis (4) intersecting with the rotation axis (3). Using (2), preparing a raw material powder composed of rapidly solidified Al alloy powder and hard particles put in the container (2a) ;
Using the billet (5) made of the raw material powder, and performing an extrusion process with a porous die (9);
A method for producing an Al-based composite member , comprising: a material (14) cut out from an extruded material (13) and a step of performing warm forging using a closed mold.   The rapidly solidified Al alloy powder is composed of 4 atomic% ≦ TM ≦ 7 atomic%, 0.5 atomic% ≦ X ≦ 3 atomic%, 1 atomic% ≦ Si ≦ 3 atomic% and the balance Al, and TM is composed of Fe and Ni. The method for producing an Al-based composite member according to claim 1, wherein at least one selected, and X is at least one selected from Ti, Zr, Mg, and rare earth elements. The hard particles are Al ₂ O ₃ particles, the average particle diameter D ₃ is 1.5 μm ≦ D ₃ ≦ 10 μm, and the volume fraction Vf is set to 0.5% ≦ Vf ≦ 20%. The method for producing an Al-based composite member according to claim 1 or 2.   The method for producing an Al-based composite member according to claim 1, 2, or 3, wherein the Al-based composite member is at least one of a valve spring retainer (1) and a valve lifter for an internal combustion engine.

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