Influence of heat treatment on microstructure and damage tolerance property in Ti-6Al-2Zr-1Mo-1V

The influence of heat treatment on the microstructure and damage tolerance property of Ti-6Al-2Zr-1Mo-1V titanium alloy was investigated. The large-thickness Ti-6Al-2Zr-1Mo-1V titanium alloy plate was produced by β-processing,following with duplex anneal in(α+β) phase field and β anneal,respectively. The fatigue crack propagation rate(da/dN) test and the fracture toughness(KⅠC) test of Ti-6Al-2Zr-1Mo-1V were performed. The results show that the annealing in(α+β) phase field,with increasing anneal temperature,prior β grain size and α colony size of Ti-6Al-2Zr-1Mo-1V remained constant approximately,α lamella mean size increases gradually;KⅠCincreases and da/dN decreases respectively;when annealing in β phase field,prior β grain size and α colony size increases sharply,da/dN decreases drastically. β anneal is better than anneal in(α+β) phase field as to improve the damage tolerance property of Ti-6Al-2Zr-1Mo-1V.

The influence of heat treatment on the microstructure and damage tolerance property of Ti-6Al-2Zr-1Mo-1V titanium alloy was investigated. The large-thickness Ti-6Al-2Zr-1Mo-1V titanium alloy plate was produced by β-processing, following with duplex anneal in （α＋β） phase field and β anneal, respectively. The fatigue crack propagation rate（da/dN） test and the fracture toughness（Kit） test of Ti-6Al-2Zr-1Mo-1V were performed. The results show that the annealing in （α＋β） phase field, with increasing anneal temperature, prior β grain size and a colony size of Ti-6Al-2Zr-1Mo-1V remained constant approximately, a lamella mean size increases gradually; KIC increases and da/dN decreases respectively; when annealing in β phase field, prior β grain size and a colony size increases sharply, da/dN decreases drastically, β anneal is better than anneal in （α＋β） phase field as to improve the damage tolerance property of Ti-6Al-2Zr-1Mo-1V.