Discontinuous yielding and microstructural evolution of Ti-40 at.% Al alloy compressed in single alpha-hcp phase region

作者：Wei Dai Xiu; Koizumi Yuichiro; Chiba Akihiko

来源：Journal of Alloys and Compounds, 2017, 693: 1261-1276.

DOI：10.1016/j.jallcom.2016.10.080

• Titanium aluminides
• Hot deformation
• Discontinuous yielding
• Twinning

We examined the hot deformation behaviors of Ti-40 at.% Al alloy via hot compression tests at temperatures in the range of 1423-1523 K (single alpha-hcp phase) at strain rates in the range of 1-0.001 s(-1). Specifically, we investigated the discontinuous yielding phenomenon and the strain rate dependence of the microstructural evolution of the alloy. Sharp drops in flow stresses occurred during hot compression at strain rates of 1 s(-1) and 0.1 s(-1), which were attributed mainly to both the multiplication of dislocations and the formation of deformation twins. The twins were determined as being of the compound type with the following twin elements: K-1: {11 (2) over bar1}, K-2: {11 (22) over bar}, eta(1): < 11<(2)over bar>6>, eta(2): < 11<(2)over bar>3 >, s = 0.232. The grains of the alpha 2-Ti3Al single phase were more significantly refined and homogenized by hot compression at a high strain rate of 1 s(-1) than at a low strain rate of 0.001 s(-1), with the assistance of the deformation twins at the high strain rate.

• 出版日期2017-2-5