Effect of Microscopic Stress and Strain on Mechanical Properties of Ti-6Al-2Zr-1Mo-1V Alloy

Analysis of the effect of constituent phases on mechanical properties is critical to the design of microstructure of titanium alloys. For this reason, the microscopic stress and strain in soft primary alpha (alpha(p)) and hard transformed beta matrix (beta(t)) were quantitatively analyzed by a microstructure-based finite element model to determine their effect on strength and ductility of Ti-6Al-2Zr-1Mo-1V alloy. The results show that microscopic stress in both alpha(p) and beta(t) shows a normal distribution. The peak stress and stress peak height of beta(t) are much larger than those of alpha(p). While, alpha(p) has large peak strain and beta(t) has large strain peak height. As alpha(p) volume fraction decreases from 49% to 12%, the contribution of beta(t) to ultimate tensile strength (UTS) and failure strain (FS) of the alloy increases from 59% to 91% and 36% to 75%, respectively. However, as the contribution of beta(t) increases, UTS of the alloy increases by 17% and FS decreases by 21%. This finding quantitatively reveals the effect of constituent phases on strength and ductility and provides a basis to the design of microstructure of titanium alloys.