Study On Microstructure And Properties Of Ti-43al-9v Alloy By Spark Plasma Sintering

TiAl-based alloys have been researched by many domestic and foreign research scholars for next generation of high-temperature light structural materials because of its low density, high melting point, high specific strength and modulus, flame-retardant capabilities and good oxidation resistance. In this paper, fine-grained Ti-43Al-9V alloys have been prepared by using powder metallurgy (Mechanical Milling + Spark Plasma Sintering). Milling processing parameters to obtain high-quality milling powder, spark plasma sintering processing parameters to obtain good quality compacts and very fine milling powder and the microstructure and mechanical properties of the sintered compacts were studied.The effects of milling time on the Ti/Al/V powders mixed for 20h were studied and the powders mixed for 20h were called ball milled for 0h. With the milling time extended, the powders agglomerated and welded together, leading to a recovery ration of 20-30%; After ball-milling for 60h, by adding PCA, powders (3-10μm) was produced with a big recovery ration of 80-90%.For the Ti/Al/V powders ball milling for 0h were Spark Plasma Sintered and the effects of sintering temperature on the microstructure and mechanical properties of the sintered compacts were researched. Sintering at 1100℃led to the formation ofγ-TiAl,α₂-Ti₃Al and a small amount of titanium. Sintering at higher than 1150℃led to the formation ofγ-TiAl,α₂-Ti₃Al and B₂; the microstructure was homogeneous. The sample sintered at 1150℃has the best overall mechanical properties, with an average hardness of 516HV, tensile strength 800℃of 463MPa, the average compressive strength at room temperature of 2362MPa, the average maximum compressive strain of 29.89%.The powders ball milled for 60h were Spark Plasma Sintered and the effects of sintering temperature on the microstructure and mechanical properties of the sintered compacts were researched. The phases of the 1000-1250℃sintered compacts areγ-TiAl,α₂-Ti₃Al and B₂. With the sintering temperature increasing, the microstructure becomes more homogeneous gradually, with an increased grain size. The compact sintered at 1150℃has the best overall mechanical properties, the average hardness of 592HV, at room temperature bend strength of 605MPa, with an average maximum compressive strain at room temperature of 29.89%, the average compressive strength of 2362MPa.