Microstructure, texture and mechanical properties of Mg-3.0Zn-0.2Ca alloys fabricated by extrusion at various temperatures
Microstructure, texture and mechanical properties of Mg-3.0Zn-0.2Ca alloys fabricated by extrusion at various temperatures
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DOI：
10.1016/j.jallcom.2015.08.215
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发表时间：
2015-12-15
影响因子：
6.2
通讯作者：
Tan, Ze-yi
中科院分区：
文献类型：
--
作者：
Li, Cheng-jie;Sun, Hong-fei;Tan, Ze-yi
在25 ~ 300℃的温度范围内对Mg-3.0Zn-0.2Ca （wt.%）合金进行挤压，系统地研究了挤压后的组织、织构和力学性能。结果表明：随着挤压温度的升高，晶粒尺寸单调增大，织构强度先增大后减小；在250℃以上挤压合金中形成了大量的纳米级析出相，冷挤压合金中最弱的基态织构与变形孪晶有关；在250℃以上挤压合金中，多种变形机制的激活和动态析出相的共同作用导致基体织构变弱，而在150℃挤压合金中，尖锐的基体织构以牺牲加工硬化速率为代价，大大提高了合金的屈服强度。拉伸伸长率最高的合金是在300℃的挤压条件下获得的。增强的成形性被认为与较弱的基底织构和动态析出物对应变硬化行为的依赖有关。在多种强化机制中，细晶强化和固溶强化对挤压态合金的强度增加起主导作用。(C) 2015 Elsevier B.V.版权所有
The Mg-3.0Zn-0.2Ca (wt.%) alloy has been extruded at temperature range of 25-300 degrees C and the resulting microstructure, texture and mechanical properties are systematically investigated. The results show that the grain size monotonically increases with the increasing of the extrusion temperature and the texture intensity increases firstly and decreases subsequently. In addition, a large number of nano-scale precipitates are formed in alloys extruded above 250 degrees C. The weakest basal texture developed in the cold extrusion alloy is related to the deformation twinning, while, the combining effects of activation of multiple deformation mechanisms and dynamic precipitates contribute to developing the weaker basal texture in alloys extruded above 250 degrees C. A sharp basal texture enhances the yield strength of alloy extruded at 150 degrees C greatly at the cost of work hardening rate. The highest elongation is achieved in the alloy extruded at 300 degrees C. The enhanced formability is considered to be associated with the dependence of the weaker basal texture and dynamic precipitates on the strain hardening behavior. Among the multiple strengthening mechanisms, the fine grain strengthening and the solid solution strengthening play a dominant role in the increment of strength for the as-extruded alloys. (C) 2015 Elsevier B.V. All rights reserved.