Effects of Y-Addition on Microstructure and Mechanical Properties of TiAl -Base Alloys

(Ti₅₀Al₅₀)_100-xY_x ternary alloys with various Y content(x(atom)=0~2.0%) were designed and smelt.The effect of Y-addition on microstructure and mechanieal properties of TiAl alloys are investigated by metallography,scanning electron microscope,3-point bending tests and so on.The results show that the Y-addition can change the microstructure of TiAl alloys such as fining the grain size of γTiAl and promoting the formation of γ+α₂ lammellar structure;Y in suitable addition amount can absorb interetitial atoms such as O and N and improve strength and ductility of TiAl alloys at ambient temperature;The strength and ductility of TiAl alloys will decrease because of the formation of new ternary compounds when Y-addition amount exceeds its solid solubility in TiAl alloys.