Effect of thermomechanical parameters on dynamically recrystallized grain size of AZ91 magnesium alloy

Dynamic recrystallization of the AZ91 alloy was studied by conducting hot compression tests at temperature range of 325–400 °C and strain rate of 0.001–1 s−1. The influence of the hot deformation variables on flow stress as well as recrystallized grain size was investigated. The results showed that by decreasing temperature and increasing strain rate, flow stress increases while dynamically recrystallized grain size decreases. A power-law relation developed between the characteristic peak strain and Zener–Hollomon parameter and the exponent was determined as 0.17. Besides, the linear regression between the Zener–Hollomon parameter and dynamically recrystallized grain size developed another power law equation, with a stress exponent equivalent to −0.13.

Research highlights▶ A power-law relation between the characteristic peak strain and Zener–Hollomon parameter was developed. ▶ A linear relationship between recrystallized grain size and Zener–Hollomon parameter, Z was extracted. The recrystallized grain size decreases by increase in Z value. ▶ It was found that the temperature is most influential thermomechanical parameters affected on the recrystallized grain size.