Study Of Hot Compression Deformation Behavior And Microstructure For ZE42 Magnesium Alloy

Mg-4Zn-0.5Er-1Y Mg alloy(ZE42 Mg alloy) is Mg-Zn-RE system alloy which contains moderate content of Zn element and a small amount of rare earth elements, this Mg alloy was recently developed by our team. ZE42 Mg alloy has good strength, ductility and weldability. In order to further develop the processing potential of this alloy, the thermal deformation properties need to be studied, therefore, this research paper established hot compression deformation constitutive equation and drawn processing map by measuring the stress- strain curve of the alloy, The microstructure can be observed in different states, as well as the range of different thermal processing parameters, the deformation behavior of thermal processing of ZE42 Mg alloy can be studied. Draw the following important conclusions:1. Activation energy Q values of constitutive equations have big difference for ZE42 Mg alloy before and after homogenization. Under conditions of peak stress and strain ε = 0.45, deformation activation energy Q value of cast specimens dropped from 257 k J / mol and 247 k J / mol to 190 k J / mol and 151 k J / mol. Cast alloy’ s linear correlation of ln Z-ln [sinh(ασ)] is poor, while it has a significant linear correlation for the alloy which after homogenization.2. By analyzing the thermal processing graph, homogenization treatment improves the energy dissipation efficiency η value, expands the area can be processed(stable area) of the alloy. The dynamic recovery and recrystallization organization can be found in cast alloy after deformation but also observed microscopic cracks, and even found a significant macroscopic cracks, in this case flow instability factor0)(.???.The deformation energy dissipation efficiency value η≥20.67% and0)(.???of the alloy after homogenization when T = 350℃ ~ 450℃, ? = 0.01s-1 ~ 0.1s-1, there has an obvious dynamic recrystallization in this range and without the presence of microscopic cracks, so this range is suitable for hot processing(stable area).3. Through observation and analysis of the microstructure, stable area is conducive to continuous dynamic recrystallization, the size of grains are fine and uniform, coordinate rotation between the fine recrystallized grains is conducive to hotcompression rheological during the hot compression, thus inhibiting crack initiation and propagation.