热处理TiAl(W,Si)合金的拉伸性能及裂纹扩展

Tensile Properties and Crack Propagation of Heat Treated TiAl(W, Si) Alloy

摘要:

对铸态Ti-46Al-0.5W-0.5Si合金进行淬火回火热处理，获得了近层片组织和双态组织。对两种不同组织的合金进行室温拉伸试验，并对试样断口和断口附近的组织进行分析，研究了拉伸断裂机制。结果表明：双态组织比近层片组织具有更好的室温塑性和抗拉强度。双态组织中的裂纹可以绕过较小的γ相颗粒，沿γ相和α2/γ片层团的界面扩展，也会以穿越层片的方式扩展。而近层片组织中的裂纹则是以沿片层和穿越片层的混合方式扩展

Abstract:

Quenching and tempering heat treatment were carried out to the as-cast Ti-46Al-0.5W-0.5Si alloy, near lamellar and duplex microstructures were obtained. Tensile properties of the heat treated alloy were tested at room temperature. The fracture surface and the cracks adjacent to the fracture zone of the specimens were investigated to analyze the tensile fracture behavior. Results show that the ductility and tensile strength of duplex structure are better than that of near lamellar structure. The cracks in duplex structure can bypass the small γ phase particles, and propagate along the interface of γ phase particles and α2/γ lamellar. The cracks also can propagate in a trans-lamellar mode. The cracks in near lamellar structure propagate in a mixed mode of inter-lamellar and trans-lamellar.