均匀化处理对挤压态Mg-Al-Zn-0.1Y合金热变形行为及织构的影响

利用250～400℃、0.01～10 s^-1 Gleeble 3500热模拟机等温热压缩试验研究了均匀化处理对稀土Y微合金化挤压态Mg-Al-Zn合金热变形行为的影响，利用电子背散射衍射(EBSD)研究了均匀化热处理对其热变形织构的影响。建立了挤压态和均匀化处理态Mg-Al-Zn-0.1Y镁合金的Arrhenius型本构方程，绘制了代表稳态流动的0.5应变加工图。研究了均匀化热处理对合金热加工图的影响，发现均匀化处理拓宽了合金低温可加工区，提升了合金的低温可加工性，确定了挤压态合金的适宜加工区为(325～375℃、0.01～0.1 s^-1)和(350～375℃、1～10 s^-1),均匀化热处理态合金的适宜加工区为(275～325℃、0.01～0.1 s^-1)。均匀化热处理提升了合金的动态再结晶能力，弱化了挤压态合金热变形基面织构强度，提升了软取向部分比例，提高了挤压态镁合金的热成形性。

Effect of homogenization treatment on hot deformation behavior and texture of extruded Mg-Al-Zn-0.1Y alloy

Taking extruded and homogenized Mg-Al-Zn-0.1Y magnesium alloy as research object, hot deformation behaviors of the alloy under isothermal hot compression at 250-400 ℃ and 0.01-10 s^-1 were studied by using a Gleeble 3500 thermal simulator to establish Arrhenius constitutive equations and processing maps, and effect of homogenization heat treatment on its deformation texture was studied by electron backscattered diffraction (EBSD). Based on the established processing map at strain of 0.5 which represents the steady-state flow, the results show that the homogenization treatment broadens the low-temperature processable zones and improves the low temperature processability of the alloy, the suitable processing zones of the as-extruded alloy are (325-375 ℃, 0.01-0.1 s^-1) and (350-375 ℃, 1-10 s^-1), and the optimum processing zone of as-homogenized alloy is (275-325 ℃, 0.01-0.1 s^-1). The EBSD results show that the homogenization treatment improves the dynamic recrystallization ability of the alloy, weakens the texture strength of the base surface of the extruded alloy, increases the proportion of soft orientation, and improves the hot formability of the extruded magnesium alloy.