Constitutive equations for elevated temperature flow stress of Ti–6Al–4V alloy considering the effect of strain

In order to study the workability of Ti–6Al–4V alloy, the experimental stress–strain data from isothermal hot compression tests, in a wide range of temperatures (800–1050 °C) and strain rates (0.0005–1 s−1), were used to develop the constitutive equation of different phase regimes (α + β and β phase). The effects of temperature and strain rate on deformation behaviors a represented by Zener–Holloman parameter in an exponent-type equation. The influence of strain was incorporated in constitutive analysis by considering the effect of strain on material constants. Correlation coefficient (R) and average absolute relative error (AARE) were introduced to verify the validity of the constitutive equation. The values of R and AARE were 0.997% and 9.057% respectively, which indicated that the developed constitutive equation (considering the compensation of strain) could predict flow stress of Ti–6Al–4V alloy with good correlation and generalization.

Research highlights
► The constitutive equation of Ti–6Al–4V alloy considering the effect of strain was proposed.
► The developed constitutive equation can precisely predict the flow stress.
► The predictability of developed constitutive equation was quantified.