Precipitation evolution and hardening in Mg-Sm-Zn-Zr alloys
Precipitation evolution and hardening in Mg-Sm-Zn-Zr alloys
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DOI：
10.1016/j.actamat.2016.03.068
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发表时间：
2016-06-01
期刊：
影响因子：
9.4
通讯作者：
Stone, Donald S.
中科院分区：
文献类型：
--
作者：
Xia, Xiangyu;Sun, Weihua;Stone, Donald S.
这项工作系统地研究了 Mg-4Sm-xZn-0.4Zr (x = 0, 0.3, 0.6, 1.3) (wt%) 合金中的析出演化及其与机械性能的对应关系。使用透射电子显微镜 (TEM)、高分辨率 TEM (HRTEM) 和高角度环形暗场扫描透射电子显微镜 (HAADF-STEM) 识别 200 摄氏度下的沉淀序列。发现随着Zn添加量的增加，出现了新的沉淀β'z。 Zn 含量较高（> 接近 1 wt%）时，基础伽马系列沉淀物占主导地位。沉淀序列的转变与力学性能的变化非常吻合。最佳 Mg-4Sm-0.3Zn-0.4Zr 合金的微观结构和性能演变是基于通过经典成核和生长模型与 CALPHAD（相图计算）模拟相结合获得的实验数据进行建模的。然后使用获得的参数来预测其他 Mg-Sm-Zn-Zr 合金在其他热处理条件下的性能。计算数据和测量数据之间存在良好的一致性，这验证了当前数据库的准确性，并为未来优化这种有前途的合金系统提供了一个强大的工具。 (C) 2016 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
Precipitation evolution and its correspondence to mechanical properties in Mg-4Sm-xZn-0.4Zr (x = 0, 0.3, 0.6, 1.3) (wt%) alloys are systematically investigated in this work. Precipitation sequences at 200 degrees C are identified using transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). A new precipitate beta'z is found to present with the increase of Zn addition. With higher Zn content (>similar to 1 wt%), basal gamma-series precipitates dominate. The transition in precipitation sequence agrees well with the change of mechanical properties. The microstructure and property evolution in the optimum Mg-4Sm-0.3Zn-0.4Zr alloy is modeled based on obtained experimental data through a combination of classical nucleation and growth model and the CALPHAD (CALculation of PhAse Diagram) simulation. The obtained parameters are then used to predict the properties of other Mg-Sm-Zn-Zr alloys under other heat treatment conditions. Good agreements are found between the calculated and measured data, which validate the accuracy of the current database and suggest a powerful tool for future optimization of this promising alloy system. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.