再结晶温度对大塑性热变形Ti–6Al–4V微观组织与力学性能的影响

Effect of recrystallization temperature on microstructures and mechanical properties of severe plastic thermo deformation Ti–6Al–4V alloy

摘要:

将Ti–6Al–4V双相钛合金加热至α+β相区,利用墩拔方式进行大塑性热变形,然后将其置于不同的温度下进行再结晶保温热处理。结果表明：材料经形变热处理后,晶粒转变为细小的等轴α晶粒以及条状α+β组织,随再结晶温度的升高,等轴α晶粒逐渐长大,条状α+β组织也逐渐变大,发生再结晶晶粒的体积分数在增加,小角度晶界所占比例减小。800℃再结晶后延伸率和断面收缩率高达19.9%及42.5%,材料的综合力学性能则随再结晶温度的升高呈下降趋势,原因归结于晶粒的粗化及晶粒的均匀性变差所致。

Abstract:

The Ti–6Al–4V alloy were thermo-forged in α+β two phase region,and then recrystallized in three different temperatures. The results show that the initial microstructure were fully transformed into fine equiaxed α and lamellar α+β,the fine equiaxed α and lamellar α+βwere gradually coarsening as increasing recrystallization temperature,the relative frequency of recrystallization grain were also increased,low angle boundary shows a converse trend. The total elongation and area reduction reach up to 19.9% and 42.5%,the mechanical properties gradually decreased as the elevate temperature which were attribute to coarse and inhomogeneous grain.