Influence of extruding temperature and heat treatment process on microstructure and mechanical properties of three structures containing Mg-Li alloy bars
Influence of extruding temperature and heat treatment process on microstructure and mechanical properties of three structures containing Mg-Li alloy bars
复制标题
DOI：
10.1016/j.msea.2017.11.114
复制
发表时间：
2018-01
期刊：
影响因子：
6.4
通讯作者：
Yan Tang;Q. Le;R. Misra;Guanqiao Su;J. Cui
中科院分区：
文献类型：
--
作者：
Yan Tang;Q. Le;R. Misra;Guanqiao Su;J. Cui
制备了密度为1.38 g/cm 3、抗拉强度为329.2 MPa的Mg-Li合金棒材。同时开发了一种简便、低成本的工业化生产工艺。在铸造合金中，随着Li含量的增加，hcp-Mg逐渐转变为bcc-Li。在不同温度挤压过程中，Mg-8Li-5Al-2 Zn-0. 5 Y合金的动态再结晶（DRX）弱于Mg-5Li-5Al-2 Zn-0. 5 Y和Mg-11. 4Li-5Al-2 Zn-0. 5 Y合金，这是由于hcp-Mg（α）和bcc-Li（β）相互制约的结果。在退火过程中，Mg-11.4Li-5Al-2 Zn-0.5Y合金在573 K时出现了晶粒异常长大，在593 K时，粗大晶粒中出现了规则的枝晶组织。此外，bcc-Li合金还表现出固溶强化行为，并显著提高了合金的强度（最高可提高约160 MPa）。通过控制冷却速度，可以实现合金的析出行为。通过高精度的数学模拟，定量分析和确定了固溶和析出过程中组织演变与合金性能的关系。
The Mg-Li alloy bars with density of 1.38 g/cm3as well as ultimate tensile strength of 329.2 MPa were fabricated. Simultaneously, an industrial process with convenience and low cost was developed. In the cast alloys, hcp-Mg was transformed gradually into bcc-Li with increasing Li content. During extruding at different temperatures, the dynamic recrystallization (DRX) in Mg-8Li-5Al-2Zn-0.5Y was weaker than Mg-5Li-5Al-2Zn-0.5Y and Mg-11.4Li-5Al-2Zn-0.5Y due to the mutual limitation between hcp-Mg (α) and bcc-Li (β). In the annealing process, abnormal grain growth in Mg-11.4Li-5Al-2Zn-0.5Y was found at 573 K, and a kind of regular dendritic structure was discovered in the coarse grains at 593 K. Additionally, a sort of solid solution strengthening behavior in bcc-Li was observed and enhanced remarkably the alloy strength (increased by ~160 MPa in maximum). Through controlling cooling velocity, a precipitation behavior could be achieved in the alloys. Through mathematical modeling with high accuracy, the relationships among microstructural evolution and alloy properties in the solid solution and precipitation processes were quantitatively analyzed and determined.