细晶Ti-6Al-4V宽幅板材的超塑性变形机理及组织演变

通过恒应变速率拉伸试验,在1103~1223 K温度范围、3.2×10-4~1×10-2s-1应变速率范围内,研究了Ti-6Al-4V宽幅板材的超塑性,在实验中获得了100%-604%的延伸率。分析了组织演变和变形机理,结果表明,其主要变形机理为晶界滑移,以晶内位错运动和β相的晶内滑移为协调机制。实验中还发现在低温下变形时,Ti-6Al-4V宽幅板材存在各向异性,当在高温下变形时,各向异性不太明显。

Superplastic deformation mechanism and simultaneous microstructure evolution of fine grained Ti-6Al-4V wide sheet

The superplasticity of fine-grained Ti-6Al-4V wide sheet was investigated by constant strain rate tensile method.The superplastic tensile tests were carried out at temperatures ranging from 1103 K to 1223 K and strain rates ranging from 3.2×10-4 s-1to 1×10-2 s-1.The results show that tensile elongation to failure values between 100% and 604% are obtained.Microstructure evolution and deformation mechanism were analyzed.Results show that the main deformation mechanism is grain boundary sliding,accommodated by matrix dislocation movement and the intragranular slip of β phase.It is also found that the Ti-6Al-4V wide sheet shows anisotropy when deformed at lower temperatures,which is obviously reduced when deformed at higher temperatures.