中國有色金屬學(xué)報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 15 No. 5 October 2005 |
（1. School of Materials Science and Engineering, Central South University,
Changsha 410083, China;
2. Institute of Yichang Measurement Technology, Yichang 443003, China）
Abstract: An AZ61 alloy was subjected to hot compression at temperatures ranging from 523K to 673K, with strain rates of 0.001-1s-1. Flow softening occurs at all temperatures and strain rates. There are peak and plateau stresses on flow curves. The initiation and evolution of dynamic recrystallization(DRX) were studied by the flow softening mechanism based on the flow curves and microstructural observations. A linear relationship was established between the logarithmic value of the critical strain for DRX initiation(lnεc) and the logarithmic value of the Zener-Hollomon parameter(lnZ). The volume fraction of DRX grain (φd) is formulated as a function of the process parameters including strain rate, temperature, and strain. The calculated values of φd agree well with the values extracted from the flow curves. The size of DRX grain(d) was also formulated as a function of the Zener-Hollomon parameter. This study suggests that DRX behavior of AZ61 can be predicated from plastic process parameters.
Key words: AZ61 magnesium alloy; dynamic recrystallization; critical strain; flow softening
