Ma Junfei, Wang Songhui, Yang Jianlei, Zhang Wencong, Chen Wenzhen, Cui Guorong, Chu Guannan
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Weihai Lightweight Materials and Forming Engineering Research Center, Weihai 264209, China.
Materials (Basel). 2022 Feb 25;15(5):1745. doi: 10.3390/ma15051745.
Isothermal hot compression experiments were conducted on Mg-2.5Nd-0.5Zn-0.5Zr alloy to investigate hot deformation behavior at the temperature range of 573-773 K and the strain rate range of 0.001 s-10 s using a Gleeble-3500D thermomechanical simulator. The results showed that the rheological curve showed a typical work hardening stage, and there were three different stages: work hardening, transition and steady state. A strain compensation constitutive model was established to predict the flow stress of the Mg-2.5Nd-0.5Zn-0.5Zr alloy, and the results proved that it had high predictability. The main deformation mechanism of the Mg-2.5Nd-0.5Zn-0.5Zr alloy was dislocation climbing. The processing maps were established to distinguish the unstable region from the working region. The maps showed that the instability generally occurred at high strain rates and low temperatures, and the common forms of instability were cracking and flow localization. The optimum machining range of the alloy was determined to be 592-773 K and 0.001-0.217 s. With the increase in deformation temperature, the grain size of the alloy grew slowly at the 573-673 K temperature range and rapidly at the 673-773 K temperature range.
采用Gleeble-3500D热机械模拟器对Mg-2.5Nd-0.5Zn-0.5Zr合金进行等温热压缩实验，以研究其在573-773K温度范围和0.001s-10s应变速率范围内的热变形行为。结果表明，流变曲线呈现典型的加工硬化阶段，存在加工硬化、转变和稳态三个不同阶段。建立了应变补偿本构模型来预测Mg-2.5Nd-0.5Zn-0.5Zr合金的流变应力，结果证明该模型具有较高的预测性。Mg-2.5Nd-0.5Zn-0.5Zr合金的主要变形机制是位错攀移。建立了加工图以区分不稳定区域和工作区域。加工图表明，不稳定性通常发生在高应变速率和低温下，不稳定的常见形式是开裂和流动局部化。确定该合金的最佳加工范围为592-773K和0.001-0.217s。随着变形温度的升高，合金的晶粒尺寸在573-673K温度范围内缓慢长大，在673-773K温度范围内快速长大。
