Hot deformation behavior and processing map of a superlight dual-phase Mg-Li alloy
Hot deformation behavior and processing map of a superlight dual-phase Mg-Li alloy
复制标题
超轻双相镁锂合金的热变形行为及加工图
DOI：
10.1016/j.jallcom.2018.07.024
复制
发表时间：
2018-10-25
影响因子：
6.2
通讯作者：
Wells, Mary
中科院分区：
文献类型：
--
作者：
Liu, Gang;Xie, Wen;Wells, Mary
通过建立本构方程和制作工艺图，研究了超轻双相Mg-9Li-3AI-2Y合金的热变形行为。基于真实应力-应变曲线，通过预测材料常数（α、β、n、Q和InA）建立本构关系。基于动态材料模型（DMM）构建了Mg-9Li-3AI-2Y合金的加工图谱。温度范围为423 ~ 450 K，应变速率范围为0.01 ~ 1s(-)(1)；温度范围为560 ~ 573 K，应变速率范围为1s（- 1）。在不稳定区观察到α - mg相孪晶和基体裂纹，在高效值区形成细化的动态再结晶（DRX）晶粒。由于材料的不稳定性，在高应变速率下发生变形是不可取的。动态再结晶首先发生在β - li相中，Al2Y粒子有利于DRX过程，具有粒子激发成核效应。β - li相延缓了a-Mg相的DRX过程。13-Li相的DRXed晶粒呈随机织构，而α - mg相的基极向法向旋转，有利于进一步变形。基于本构关系、加工图和织构演化，Mg-9Li-3Al-2Y合金在较宽的温度和应变速率下易发生变形。(C) 2018 Elsevier B.V.版权所有
Hot deformation behavior of a superlight dual phase Mg-9Li-3AI-2Y alloy was investigated by developing constitutive equations and constructing processing maps. Constitutive relationship was established by the prediction of materials constants (alpha, beta, n, Q and InA) based on true stress-strain curves. Processing maps were constructed for Mg-9Li-3AI-2Y alloy based on dynamic materials model (DMM). The instability domains occurred over a narrow temperature range of 423-450 K and strain rate range of 0.01-1s(-)(1), and over a temperature range of 560-573 K and close to strain rate of 1s (-1). The twinning in alpha-Mg phase and cracks in the matrix were observed in the instability domains, the refined dynamic recrystallization (DRX) grains were formed in the regions with high efficiency values. It is undesirable to deform at high strain rates for mechanical properties because of the instability. Dynamic recrystallization occurs first in beta-Li phases, and the Al2Y particles were conducive to the DRX process with particle stimulated nucleation effect. The DRX process of a-Mg phase was retarded by beta-Li phase. The DRXed grains of 13-Li phase showed a random texture, while the basal poles of alpha-Mg phase rotated towards the normal direction, which can enhance the further deformation. Based on constitutive relationship, processing map and texture evolution, the Mg-9Li-3Al-2Y alloy is easy to suffer from deformation at a wide range of temperatures and strain rates. (C) 2018 Elsevier B.V. All rights reserved.