JP2010059480A - METHOD FOR PRODUCING Ti PARTICLE-DISPERSED MAGNESIUM-BASED COMPOSITE MATERIAL - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Ti particle-dispersed magnesium-based composite material having excellent strength by uniformly dispersing titanium particles into a magnesium matrix and improving boundary adhesion between titanium and magnesium. <P>SOLUTION: The Ti particle-dispersed magnesium-based composite material is obtained by uniformly dispersing titanium particles into the matrix of magnesium. Magnesium composing the matrix and the titanium particles are coupled so as to exhibit satisfactory wettability without interposing titanium oxides in their boundaries, thus the material has a tensile strength of ≥230 MPa. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a magnesium alloy, and in particular, by improving both strength and ductility, titanium (Ti) particle-dispersed magnesium-based composite that can be used in a wide range of fields such as home appliances, automotive parts, and aircraft members. The present invention relates to a material and a manufacturing method thereof.

  Magnesium (Mg) has the smallest specific gravity among industrial metal materials, and is expected to be used for parts and components such as motorcycles, automobiles, and aircraft that have strong needs for weight reduction. However, since the strength is not sufficient compared with conventional industrial materials such as steel materials and aluminum alloys, the use of magnesium alloys is currently limited.

  In order to solve such a problem, development of a composite material in which particles or fibers having properties higher in strength and hardness than magnesium are dispersed as the second phase is being advanced. Titanium (Ti) is considered as an effective second phase to be dispersed. When comparing the rigidity, it is Mg: 45 GPa, Ti: 105 GPa, and comparing the hardness, Mg: 35-45 Hv (Vickers hardness), Ti: 110-120 Hv, so the titanium particles are dispersed in the magnesium substrate By doing so, an effect of improving the strength and hardness of the magnesium-based composite material can be expected.

  Also, in conventional composite materials, the dispersion of ceramic particles such as oxides, carbides and nitrides and ceramic fibers has been the mainstream, but these particles and fibers all have high rigidity and hardness, but are not ductile. Because they are scarce, they reduce the ductility (eg, elongation at break) of the composite material itself when dispersed in the magnesium alloy. On the other hand, since titanium is a metal and itself has excellent ductility, there is no problem of reducing the ductility of the composite material when titanium particles are added to and dispersed in magnesium.

  On the other hand, magnesium has a problem of inferior corrosion resistance. This has the characteristic that magnesium is a base, and for example, the standard electrode potential Es (hydrogen H is set to zero V) is as small as -2.356V. For example, when a small amount of iron (Fe: Es = −0.44V) or copper (Cu: Es = + 0.34V) is contained in such magnesium, galvanic corrosion is caused by a potential difference between Mg—Fe and Mg—Cu. The phenomenon progresses. On the other hand, the standard electrode potential of titanium is −1.75 V, and the potential difference with Mg is smaller even when compared with aluminum (Al: Es = 1.676 V) which is an additive element to Mg. That is, it can be said that the influence on the corrosion phenomenon by dispersing titanium in magnesium is small.

  From the above, it is considered effective to use titanium particles as a dispersion reinforcing material in a magnesium base.

  As a technique related to the Ti particle-dispersed magnesium composite material reported so far, for example, Non-Patent Document 1, Outline of the Japan Institute of Metals (March 26, 2008) p. 355, no. 464 (Kataoka, Hokuto: Influence of microstructure on mechanical properties of Ti particle-dispersed Mg-based composites), Non-Patent Document 2, Outline of Light Metal Society Presentation (May 11, 2008) p. 13, no. 7 (Hokkaido, Kataoka, Komatsu: Influence of titanium particle addition on mechanical properties of magnesium), Non-Patent Document 3, Summary of Powder Powder Metallurgy Lecture (June 6, 2007) p. 148, no. 2-51A (Inami, Fujita, Ohara, Igarashi: Development of magnesium composite material by bulk mechanical alloying method), Non-Patent Document 4, Powder and Powder Metallurgy, Vol. 55, No. 4 (2008), p. 244 (Maminami, Fujita, Motoe, Ohara, Igarashi, Kondo: Development of magnesium composite material by bulk mechanical alloying method), Non-Patent Document 5, Light Metal, Vol. 54, No. 11 (2004), p. 522-526 (Sato, Watanabe, Miura, Miura: Development of titanium particle-dispersed magnesium-based functionally gradient material by centrifugal solid phase method).

  In Non-Patent Document 1 and Non-Patent Document 2, pure titanium particles are dispersed on the surface of a pure magnesium plate, and heated and pressed in a state where the pure magnesium plate is placed thereon, thereby the titanium particles are made of pure magnesium plate. It is disclosed that a composite material in a sandwiched state is manufactured, and further, this composite material is stacked and heated and pressed to prepare a Ti particle-dispersed magnesium-based composite material in which titanium particles are arranged in the plane direction of the plate. Yes.

  In Non-Patent Document 3 and Non-Patent Document 4, a magnesium alloy powder and a pure titanium powder are mixed and subjected to hot extrusion after continuously giving a strong plastic working in a state filled in a mold. To manufacture a Ti particle-dispersed magnesium-based composite material.

  In any case of the above non-patent documents 1 to 4, the heating temperature is set to a temperature sufficiently lower than the melting point of magnesium, and the composite material is produced in a complete solid phase temperature range without melting. As a result of the tensile test for each composite material, although an increase in strength of about 5 to 10% was confirmed as compared with the material without adding Ti particles, the ductility (breaking elongation) was reduced by about 20 to 30%. . This is because magnesium and titanium do not form a compound, so that the strength of the bonding interface between the two is not sufficient, and thus the strength is not sufficiently improved. On the other hand, it is recognized that the interface becomes a stress concentration part and ductility is reduced.

  As described above, in order to significantly improve both strength and ductility in the titanium particle-dispersed magnesium-based composite material, it is necessary to improve the adhesion at the Mg—Ti interface.

In Non-Patent Document 5, a centrifugal force is applied to a molten magnesium or magnesium alloy (AZ91D) containing titanium particles present as a solid phase, and the difference is caused by a difference in centrifugal force caused by a density difference between the dispersed particles and the molten metal. A manufacturing method is described in which the composition gradient is controlled using a difference in moving speed. Since the specific gravity of titanium is more than twice the specific gravity of magnesium, it is difficult to uniformly disperse titanium particles in a molten magnesium or magnesium alloy by the centrifugal solid phase method disclosed in Non-Patent Document 5. . Actually, this document states that “it was difficult to disperse titanium particles by this method”. Furthermore, in this document, when titanium particles are introduced into a molten magnesium alloy containing aluminum (AZ91D) and the centrifugal solid phase method is applied, the aluminum concentration in the titanium particle agglomerated portion is very high. In addition, it is described that there was a region where aluminum was dissolved in the outer peripheral portion of the titanium particles. The reason for this is that, in this document, there is a possibility that an initial melt with a high aluminum concentration permeates between titanium particles by capillary action and participates in the aggregation and sintering. Thus, an AZ91D alloy containing aluminum It has been found that the use of the centrifugal solid phase method has a problem in view of the melt composition. "
Outline of the Japan Institute of Metals (March 26, 2008) p. 355, no. 464 (Kataoka, Hokuto: Influence of microstructure on mechanical properties of Ti particle-dispersed Mg-based composites) Outline of the Japan Institute of Light Metals (May 11, 2008) p. 13, no. 7 (Hokkaido, Kataoka, Komatsu: Effect of titanium particle addition on the mechanical properties of magnesium) Powder Powder Metallurgy Lecture (June 6, 2007) p. 148, no. 2-51A (Inami, Fujita, Ohara, Igarashi: Development of magnesium composite material by bulk mechanical alloying method) Powder and Powder Metallurgy, Vol. 55, No. 4 (2008), p. 244 (Inami, Fujita, Motoe, Ohara, Igarashi, Kondo: Development of magnesium composites by bulk mechanical alloying) Light Metal, Vol. 54, No. 11 (2004), p. 522-526 (Sato, Watanabe, Miura, Miura: Development of functionally graded magnesium-based functionally dispersed titanium particles by centrifugal solid phase method)

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to achieve excellent dispersion by uniformly dispersing titanium particles in a magnesium substrate and improving interfacial adhesion between titanium and magnesium. It is to provide a Ti particle-dispersed magnesium-based composite material having high strength.

  The Ti particle-dispersed magnesium-based composite material according to the present invention is obtained by uniformly dispersing titanium particles in a magnesium substrate. The feature is that the magnesium and titanium particles constituting the substrate are bonded with good wettability without interposing titanium oxide at the interface between them, and the magnesium-based composite material is 230 MPa or more. It has a tensile strength.

  According to the present invention, a magnesium-based composite material having a high tensile strength of 230 MPa or more can be obtained because an appropriate amount of titanium particles exhibits good wettability in the magnesium substrate and is uniformly dispersed.

  One embodiment of the present invention is directed to a powder for producing the above Ti particle-dispersed magnesium-based composite material. This powder can be obtained by machining a cast material in which titanium particles are uniformly dispersed in a magnesium base so as to become a powder.

  The powder according to another embodiment of the present invention is a powder for producing the above Ti particle-dispersed magnesium-based composite material, and a molten magnesium in which titanium particles are uniformly dispersed is solidified into a powder by an atomizing method. To obtain.

  A method for producing a Ti particle-dispersed magnesium-based composite material according to the present invention includes a step of introducing titanium particles into a magnesium melt, a step of stirring the melt so that the titanium particles are uniformly dispersed in the melt, A step of obtaining a composite material in which titanium particles are uniformly dispersed in a magnesium substrate, and a step of subjecting the composite material to hot plastic processing to obtain a magnesium-based composite material having a tensile strength of 230 MPa or more. Is provided.

  In one embodiment, the step of obtaining the composite material includes obtaining a cast material in which the molten metal is solidified and titanium particles are dispersed in a magnesium base, and the cast material is subjected to machining to obtain a powder form. And solidifying the powder to obtain a green compact.

  In another embodiment, the step of obtaining the composite material includes solidifying the molten metal into a powder by an atomizing method, and compacting the powder to obtain a compacted body.

  In another aspect, a method for producing a Ti particle-dispersed magnesium-based composite material according to the present invention includes a step of mixing magnesium powder and titanium particles, and the mixed powder is held at a temperature higher than the liquid phase generation temperature of the magnesium powder. A step of sintering and solidifying the mixed powder held at a high temperature, and a step of subjecting the sintered solidified body to hot plastic working to obtain a magnesium-based composite material having a tensile strength of 230 MPa or more. .

  The technical significance or effects of the configuration of the present invention described above will be described in detail in the following items.

  In order to develop a titanium particle-dispersed magnesium composite material capable of improving the interfacial adhesion between titanium and magnesium, the inventors of the present application focused on the wettability of both, evaluated the characteristics, and achieved excellent wetting. The manufacturing method of the composite material using the property was investigated.

(1) Wettability between pure magnesium and pure titanium The inventors of the present application investigated wettability between a pure titanium plate and pure magnesium droplets. Specifically, pure magnesium droplets melted in a high vacuum state (maintained at 800 ° C.) are statically placed on the surface of the pure titanium plate from the tip of the magnesium oxide (MgO) nozzle, and pure Mg and pure at 800 ° C. The wettability with Ti was evaluated by continuous shooting. The result is shown in FIG.

  As shown in FIG. 1, the wetting angle was about 50 ° at the time of contact with the Ti plate surface (t = 0 second), and the wetting angle decreased with time and reached 13 ° after 6 minutes. Generally, when the wetting angle is less than 90 °, it is determined that a wetting phenomenon has occurred, and the wettability improves as the value approaches 0 °. Titanium carbide (TiC), which is said to have good wettability with magnesium, has a wetting angle of about 33 ° at 900 ° C (reference: A. Contrerasa et al .: Scripta Materialia, 48 (2003) 1625-1630). Considering, it is recognized that the wettability between pure Mg and pure Ti is very good.

  After the wettability evaluation, the interface between the pure Mg and the titanium plate after solidification on the test piece was observed with a scanning electron microscope (SEM). The result is shown in FIG. It can be seen that the molten Mg is in good contact with the titanium plate without gaps or voids over the entire area.

  For comparison, a composite material as reported in the prior art (Non-Patent Documents 1 to 4), that is, a composite in which a mixed powder of pure titanium powder and pure magnesium powder is heated and pressed at a solid phase temperature of magnesium powder. Materials were prepared and the bonding interface between the two was observed. The result is shown in FIG. In producing the composite material, the heating temperature was set to 520 ° C., and the temperature was set lower than the melting point of pure magnesium (650 ° C.) to obtain a completely solid state. As indicated by the arrows, a large number of gaps / voids are observed at the interface between the Ti particles and the Mg substrate, indicating that the adhesion is not sufficient. Therefore, in the manufacturing method disclosed in the prior art, the adhesion between Mg and Ti is not sufficient because it is heated and sintered at a solid phase temperature lower than the melting point of Mg. As a result, the strength and ductility of the composite material It is considered that the improvement was not obtained.

(2) Composite Material Using Molten Ti Particle Dispersed Magnesium Based on the above results, the present inventors have developed the following method to improve the adhesion of the interface between the magnesium base and Ti particles. A matrix composite material was prepared. First, the molten magnesium was held at a temperature higher than the melting point of magnesium or magnesium alloy constituting the substrate, and an appropriate amount of Ti particles was added to the molten metal. The molten metal was sufficiently stirred so that the titanium particles were uniformly dispersed in the molten metal, and then the molten metal was solidified. In the magnesium-based composite material produced by such a manufacturing method, magnesium and titanium particles constituting the substrate exhibit excellent wettability without interposing titanium oxide at the interface between them, and excellent adhesion Have joined. By subjecting this magnesium-based composite material to hot plastic working, a Ti particle-dispersed magnesium-based composite material having a tensile strength of 230 MPa or more could be obtained.

  A composite material in which titanium particles are uniformly dispersed in a magnesium substrate can be produced by a conventional casting method, die casting method, or the like. Further, these cast materials can be made into powder by machining such as cutting and grinding. In the magnesium-based composite powder thus obtained, the titanium particles are uniformly dispersed in the magnesium base. An example of the structure photograph of this magnesium-based composite powder is shown in FIG. As is apparent from FIG. 4, no voids are observed at the interface between the Ti particles and the Mg substrate, and it is recognized that the film has good adhesion.

  A magnesium-based composite powder in which titanium particles are uniformly dispersed in a magnesium substrate can also be obtained by solidifying a molten magnesium in which titanium particles are uniformly dispersed by an atomizing method. As a specific method, the present inventors dissolved pure magnesium in a carbon crucible, added 3 mass% of pure titanium powder (average particle size: 29.8 μm) into the molten metal, and after sufficiently stirring The molten metal was discharged as a molten metal stream from the bottom of the crucible, and high pressure water was injected into the molten metal stream (water atomization method) to obtain a solidified powder. FIG. 5 shows an appearance photograph of the obtained powder and a structure observation result inside the powder. Also in this water atomized powder, it is recognized that there is no void at the interface between the Ti particles and the Mg substrate, and that the powder has good adhesion.

  As described above, after adding titanium particles into the molten magnesium and sufficiently stirring the mixture, a magnesium-based composite material is obtained by casting or die casting, or magnesium in which titanium particles are uniformly dispersed In any case where the molten metal is directly pulverized by the atomization method, the titanium particles and the base magnesium are bonded with excellent wettability and good adhesion without voids.

  After heating the Ti particle-dispersed magnesium-based composite material produced by casting or die casting to a predetermined temperature, the material is subjected to hot plastic processing such as hot extrusion, hot rolling, and forging. As a result, the crystal grains of the substrate are refined and the strength of the composite material is further improved. For example, the tensile strength of the composite material is 230 MPa or more.

  In addition, Ti particle-dispersed magnesium-based composite powder produced by machining such as cutting from a cast material, or Ti particle-dispersed magnesium-based composite powder obtained by injecting high-pressure water or high-pressure gas into a molten metal stream is compacted and solidified. Composite powders are metallurgically bonded by producing green compacts and sintered solidified bodies, followed by hot plastic processing such as hot extrusion, hot rolling and forging, as necessary. Alternatively, it is possible to create a sintered Ti particle-dispersed magnesium-based composite material.

  In the above embodiment, an appropriate amount of titanium particles is introduced into the molten magnesium. However, as another embodiment, a Ti particle-dispersed magnesium-based composite material can be obtained by the following manufacturing method. In this embodiment, magnesium powder and titanium particles are mixed, and the mixed powder is held at a predetermined temperature and sintered and solidified. What is important here is to maintain the mixed powder at a temperature higher than the liquid phase generation temperature of the magnesium powder. By maintaining such a high temperature, in the sintered solidified body after sintering, the magnesium and titanium particles constituting the substrate have good wettability without interposing titanium oxide at the interface between them. It will be bonded with excellent adhesiveness. By subjecting this sintered solidified body to hot plastic working, a Ti particle-dispersed magnesium-based composite material having a tensile strength of 230 MPa or more can be obtained.

  A pure magnesium lump having a purity of 99.8% and a titanium powder having an average particle diameter of 29.8 μm were prepared as starting materials. Pure magnesium lump is melted by heating to 750 ° C in a carbon crucible, and the above Ti particles are added to the molten metal under three conditions of 0.5 mass%, 1.5 mass%, and 2.8 mass% as a whole. did. Thereafter, in order to prevent segregation of Ti particles and sedimentation to the bottom, the molten metal was sufficiently uniformly stirred, and then a Ti particle-dispersed magnesium-based composite powder was produced by a water atomization method.

  On the other hand, pure magnesium powder (average particle size 162 μm) having a purity of 99.9% was prepared as a comparison, and both were adjusted so that the ratio of the Ti powder was 0.5 mass%, 1.5 mass%, and 2.8 mass%. After weighing, it was mixed using a dry ball mill to prepare a Mg—Ti mixed powder.

  These powders are filled in a carbon mold and pressed at 550 ° C. for 30 minutes (pressing force: 30 MPa) in a vacuum atmosphere using a discharge plasma sintering apparatus, so that the powders are sintered and solidified to have a diameter of 45 mm. An extrusion billet was prepared. Each Ti particle-dispersed magnesium powder billet was held at 200 ° C. for 5 minutes in an argon gas atmosphere and immediately subjected to hot extrusion (extrusion ratio: 37) to produce a round bar extruded material having a diameter of 7 mm.

  For comparison, a round bar extruded material was also produced for pure magnesium powder containing no Ti particles based on the above production procedure.

  Tensile test pieces were collected from the obtained three kinds of magnesium powder extrudates and subjected to a tensile strength test at room temperature. FIG. 6 shows stress-strain curves in extruded materials using pure Mg powder containing no Ti particles and Mg powder containing 2.8 mass% Ti particles produced by two production methods.

  Compared with the strength and elongation characteristics of pure magnesium powder extrudate containing no Ti particles, the tensile strength and yield strength of the Ti particle-dispersed magnesium-based composite powder extrudate using the water atomization method according to the present invention is about 35-40%. In addition, the elongation at break was equivalent and showed a high value of 15% or more.

  On the other hand, in the extruded material produced using the mixed powder of Ti particles and Mg powder as a comparative material, the tensile strength and the proof stress slightly increased by about 3 to 6%, but the elongation at break decreased to less than 10%. . When the fracture surface of the sample after the tensile test was observed, cracks progressed at the interface between the Ti particles and the magnesium substrate in the comparative material, and because the adhesion between the two was not sufficient, the effect of improving the strength by adding Ti particles was obtained. It was admitted that there was not.

  FIG. 7 shows changes in tensile strength (TS) and proof stress (YS) of each extruded material with respect to Ti addition amount. In the Ti particle-dispersed magnesium-based composite powder extruded material using the water atomization method according to the present invention, both the tensile strength and the proof stress are increased with an increase in the Ti particle content. The effect of strengthening was confirmed. As described above, this is a result of improved adhesion between the Ti particles and magnesium in the molten metal due to excellent wettability.

  On the other hand, when sintered and extruded and solidified in the solid phase temperature range using a conventional mixed powder of Ti powder and Mg powder, the tensile strength of the extruded material and It was recognized that the yield strength tended to decrease and the dispersion strengthening by the Ti particles was not sufficient.

  As in Example 1, a pure magnesium lump having a purity of 99.8% and a titanium powder having an average particle size of 29.8 μm were prepared as starting materials. The magnesium lump was melted by heating to 750 ° C. in a carbon crucible, and the above Ti particles were added to the molten metal under three conditions of 1 mass, 3 mass%, and 5 mass% in the whole weight ratio. Thereafter, in order to prevent segregation of Ti particles and settling to the bottom, the molten metal was sufficiently uniformly stirred, and then cast into a cylindrical mold to produce a billet having a diameter of 60 mm. A billet for extrusion having a diameter of 45 mm was prepared from each cast billet by machining, each billet was held at 200 ° C. for 5 minutes in an argon gas atmosphere, and immediately subjected to hot extrusion (extrusion ratio: 37) to have a diameter of 7 mm. A round bar extruded material was prepared.

  The optical microscope observation result of each extruded material is shown in FIG. As the Ti particle addition amount increases, the proportion of Ti particles in the extruded material also increases, and even when 5 mass% of Ti particles are added, there is no aggregation or segregation phenomenon of Ti particles, and it is uniformly in the magnesium substrate. It can be seen that they are dispersed.

  Table 1 shows the tensile test results of each extruded material.

  As in Example 1, in the extruded material obtained by subjecting the Ti particle magnesium-based composite material produced using the casting method according to the present invention to extrusion, as the Ti particle content increases, the tensile strength increases. Both the thickness and the proof stress increase, and there is no significant decrease in the elongation at break. From the above results, in the Ti particle-dispersed magnesium-based composite material according to the present invention, the strength of the magnesium material can be improved by the addition of Ti particles without accompanying aggregation and segregation of Ti particles.

  As in Example 1, a pure magnesium lump having a purity of 99.8% and a titanium powder having an average particle size of 29.8 μm were prepared as starting materials. The magnesium lump was melted by heating to 750 ° C. in a carbon crucible, and the Ti particles were added to the molten metal under the conditions of 2 mass% and 4 mass%, respectively, in the total weight ratio. Thereafter, in order to prevent segregation of Ti particles and settling to the bottom, the molten metal was sufficiently uniformly stirred, and then cast into a cylindrical mold to produce a billet having a diameter of 60 mm. Chips having a total length of 1 to 4 mm were produced from each cast billet by cutting.

  As a result of observing the structure of each chip, the Ti particles were uniformly dispersed in the Mg substrate without being aggregated or segregated. Then, the chips were filled in a SKD11 mold and a pressure of 600 MPa was applied by a hydraulic press to produce a powder compact billet having a diameter of 45 mm. Each billet was held at 300 ° C. for 5 minutes in an argon gas atmosphere, and immediately subjected to hot extrusion (extrusion ratio: 37) to produce a round bar extruded material having a diameter of 7 mm.

  Tensile test specimens were collected from each of the magnesium powder extrudates and subjected to a tensile strength test at room temperature. With the extrudates using chips containing 2 mass% Ti, tensile strength: 264 MPa, elongation at break: 15. In the extruded material using the chips containing 4% and 4 mass% Ti, tensile strength: 294 MPa and elongation at break: 13.74% were obtained. As the addition amount of the Ti particles is increased, the tensile strength is increased without significantly decreasing the elongation at break, and when the properties of the comparative materials described in Example 1 are compared, the same amount of Ti particles is obtained. Even when it is included, the tensile strength and the proof stress are clearly increased.

  From the above results, in the Ti particle-dispersed magnesium-based composite material obtained by the above-described production method of the present invention, the strength of the magnesium material can be improved by the addition of Ti particles without accompanying aggregation and segregation of Ti particles.

  As in Example 1, a pure magnesium lump having a purity of 99.8% and a titanium alloy powder (Ti-6.1Al% -3.8V / mass%) having an average particle diameter of 22.8 μm were prepared as starting materials. The magnesium lump was heated and melted at 750 ° C. in a carbon crucible, and the Ti alloy particles were added to the molten metal under three conditions of 1 mass%, 3 mass%, and 5 mass% in the total weight ratio. Thereafter, in order to prevent segregation of Ti alloy particles and sedimentation to the bottom, the molten metal was sufficiently subjected to uniform stirring treatment, and then cast into a cylindrical mold to produce a billet having a diameter of 60 mm.

  A billet for extrusion having a diameter of 45 mm was prepared from each cast billet by machining, each billet was held at 200 ° C. for 5 minutes in an argon gas atmosphere, and immediately subjected to hot extrusion (extrusion ratio: 37) to have a diameter of 7 mm. A round bar extruded material was prepared. And the tension test piece was extract | collected from each magnesium powder extruded material, and the tension test was done at normal temperature.

  The results are shown in Table 2. In addition, the tensile strength of the extrusion material at the time of using the pure Ti particle | grains described in Example 2 was used as a comparative value.

  Even when Ti-6Al-4V alloy powder is used, in the Ti particle-dispersed magnesium-based composite material according to the present invention, Ti alloy particles are uniformly dispersed in the substrate without agglomeration and segregation, and the amount added is increased. Accordingly, the tensile strength is increased, and the amount of increase in tensile strength is increased as compared with the case where pure Ti particles are added. That is, the strength of the magnesium composite material is further improved by further increasing the hardness and strength of the dispersed particles.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention can be advantageously used as a Ti particle-dispersed magnesium-based composite material having excellent strength and a method for producing the same.

It is the figure and photograph for evaluating the wettability of pure magnesium and pure titanium. It is the photograph which observed the interface of pure magnesium and pure titanium with the scanning electron microscope. It is the photograph which observed the interface of both in the composite material obtained after heating and pressurizing the mixed powder of pure titanium powder and pure magnesium powder with the scanning electron microscope. It is an example of the structure | tissue photograph of the magnesium group composite powder in which the titanium particle was disperse | distributed inside. It is the external appearance photograph and structure | tissue observation photograph of Ti particle dispersion | distribution magnesium group composite powder obtained by the water atomization method. It is a figure which shows the stress-strain curve of the extrusion material using the pure magnesium powder which does not contain a titanium particle, and the Ti particle dispersion | distribution magnesium group composite powder produced by two manufacturing methods. It is a figure which shows the change of the tensile strength (TS) and proof stress (YS) of each extrusion material with respect to titanium addition amount. It is the optical microscope observation photograph of each extrusion material which changed content of the titanium particle.

Claims (7)

In a Ti particle-dispersed magnesium-based composite material in which titanium particles are uniformly dispersed in a magnesium substrate,
The magnesium and titanium particles constituting the substrate are bonded with good wettability without interposing titanium oxide at the interface between them, and have a tensile strength of 230 MPa or more. Ti-particle-dispersed magnesium-based composite material. A powder for producing the Ti particle-dispersed magnesium-based composite material according to claim 1,
A Ti particle-dispersed magnesium-based composite powder obtained by machining a cast material in which titanium particles are uniformly dispersed in a magnesium base so as to become powder. A powder for producing the Ti particle-dispersed magnesium-based composite material according to claim 1,
A Ti particle-dispersed magnesium-based composite powder obtained by solidifying magnesium melt in which titanium particles are uniformly dispersed into a powder form by an atomizing method. Introducing titanium particles into the molten magnesium;
Stirring the molten metal so that the titanium particles are uniformly dispersed in the molten metal;
A step of solidifying the molten metal to obtain a composite material in which the titanium particles are uniformly dispersed in a magnesium base;
And a step of subjecting the composite material to hot plastic working to obtain a magnesium-based composite material having a tensile strength of 230 MPa or more. The step of obtaining the composite material includes obtaining a casting material in which the molten metal is solidified and titanium particles are dispersed in a magnesium base;
Machining the cast material into a powder;
The method for producing a Ti particle-dispersed magnesium-based composite material according to claim 4, comprising solidifying the powder to obtain a green compact. The step of obtaining the composite material includes solidifying the molten metal into a powder by an atomization method;
The method for producing a Ti particle-dispersed magnesium-based composite material according to claim 4, comprising solidifying the powder to obtain a green compact. Mixing magnesium powder and titanium particles;
Maintaining the mixed powder at a temperature higher than the liquid phase generation temperature of the magnesium powder;
Sintering and solidifying the mixed powder held at the high temperature;
And a step of subjecting the sintered solidified body to hot plastic working to obtain a magnesium-based composite material having a tensile strength of 230 MPa or more.