Quasi-static and dynamic plastic deformation behavior in titanium with vanadium addition

Compressive properties, microstructure features and deformation modes were investigated in binary Ti-(2,4,8) wt% V alloys during quasi-static (1 × 10−3 s−1) and dynamic (3 × 103 s−1) compressions. The compressive behavior shows a strong dependence on the loading strain rate and vanadium content contained in pure Ti, such that the flow stress increases with the increase in strain rate and vanadium content ranging from 2 wt% to 8 wt%. The microstructure features are clearly different from each other for alloys with different vanadium contents or under quasi-static and dynamic loading conditions. An examination of deformation microstructures by optical microscopy and electron backscattered diffraction indicates that twinning behavior occurs during quasi-static and dynamic compressions and the twinning density increases with strain rate increasing but decreases with vanadium addition. The existence of 101¯2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left\{ {10\bar{1}2} \right\}$$\end{document}, 112¯1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left\{ {11\bar{2}1} \right\}$$\end{document} and 112¯2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left\{ { 1 1 {\bar{{2}}{2}}} \right\}$$\end{document} type twinning was further identified. With the help of the calculated Schmid factor map, the values of critical resolved shear stress of twinning types mentioned above have been obtained and verified to be rarely affected by the loading strain rate but sensitive to the vanadium content. In vanadium-rich alloys (Ti-8V), twins are rarely observed but dislocation slip mechanism is active by transmission electron microscopy investigations. With vanadium content increasing, both the critical resolved shear stress of twinning types and the content of β phase with abundant slip systems increase, reflecting a suppression of twinning but an active dislocation slip mechanism.