An empirical analysis of titanium stress-strain curves

Stress-strain curves of titanium of two purity levels were analyzed by a Criissard and Jaoul method that assumes the Ludwik equation υ= υ0 + kεpn in the form where υ is the true stress andεp the true plastic strain. The analysis shows that High purity titanium conforms to a simpler behavior pattern than commercial purity titanium. In the absence of twinning the deformation behavior of high purity titanium can be described by a single power law, while that of commercial purity titanium is better portrayed in terms of two power laws; one holding for Small strains and the other for large. However, dynamic strain aging produces a single power law description in commercial purity titanium between 400 and 700 K. The Hollomon method was also applied to the data. This analysis was less sensitive to changes in deformation behavior.