Effect of ball milling speed and sintering temperature on microstructure and properties of TiAl alloy prepared by powder metallurgy

摘要

In order to obtain high-quality composite powder for vacuum hot pressing sintering and TiAl alloy with good microstructure and properties, the effect of ball milling speed on the morphology of composite powder and the effect of sintering temperature on the microstructure and mechanical properties of the alloy were studied. The research results show that lower ball mill speed is beneficial to achieve the effect of uniform mixing of powder, excessive rotation speed of ball mill will lead to agglomeration and cold welding of composite powder. Three sintering temperatures give three typical structures of TiAl alloy, the matrix phase content of γ-TiAl and α_2-Ti_3Al changes with the sintering temperature, the increase in sintering temperature makes the alloy structure more uniform and the density also increases. When the sintering temperature rises to 1300°C, the density of the alloy reaches 4.419g/cm~3, the hardness value of the hot-pressed alloy at 2h/1240°C is the highest, and the value of hardness is 527.14HV.