Zhang Yang, Song Leipeng, Chen Xiaoyang, Lu Yalin, Li Xiaoping
Key lab of advanced material design and additive manufacturing of Jiangsu Province, Jiangsu University of Technology, Changzhou 213001, China.
Materials (Basel). 2018 Aug 21;11(9):1490. doi: 10.3390/ma11091490.
In this study, the effect of Zn and Ca addition on microstructure and strength at room temperature of Mg-Sn alloys was investigated by comparison of Mg-6Sn, Mg-6Sn-2Zn, and Mg-6Sn-2Zn-1Ca alloys in as-cast and as-extruded states. In the as-cast samples, α-Mg and Mg₂Sn phases were the main phases of Mg-6Sn and Mg-6Sn-2Zn alloys, while the CaMgSn phase was formed in Mg-6Sn-2Zn-1Ca alloy due to the addition of the Ca element. Mg₂Sn phase dissolved into the matrix during homogenization while CaMgSn phase remained. Incomplete dynamic recrystallization (DRX) took place in these alloys during hot extrusion. Fine Mg₂Sn precipitates were observed in α-Mg matrix of as-extruded samples. Zn showed little influence on microstructure, whereas Ca reduced the volume fraction of un-DRXed grains and increased the size of DRXed grains. As-extruded Mg-Sn alloys exhibited typical fiber texture. The strength at room temperature of Mg-Sn alloys improved significantly after hot extrusion. The addition of Zn element was beneficial to the strength at room temperature of the Mg-6Sn alloy, while the further addition of Ca element was harmful to the strength. Among these alloys, the Mg-6Sn-2Zn alloy exhibited the best strength at room temperature in both as-cast and as-extruded states.
在本研究中，通过对比铸态和挤压态的Mg-6Sn、Mg-6Sn-2Zn和Mg-6Sn-2Zn-1Ca合金，研究了添加Zn和Ca对Mg-Sn合金室温下微观结构和强度的影响。在铸态样品中，α-Mg和Mg₂Sn相是Mg-6Sn和Mg-6Sn-2Zn合金的主要相，而由于添加了Ca元素，在Mg-6Sn-2Zn-1Ca合金中形成了CaMgSn相。在均匀化过程中，Mg₂Sn相溶解到基体中，而CaMgSn相保留下来。这些合金在热挤压过程中发生了不完全动态再结晶（DRX）。在挤压态样品的α-Mg基体中观察到细小的Mg₂Sn析出物。Zn对微观结构影响较小，而Ca降低了未再结晶晶粒的体积分数并增加了再结晶晶粒的尺寸。挤压态的Mg-Sn合金呈现出典型的纤维织构。热挤压后，Mg-Sn合金的室温强度显著提高。添加Zn元素有利于Mg-6Sn合金的室温强度，而进一步添加Ca元素则对强度有害。在这些合金中，Mg-6Sn-2Zn合金在铸态和挤压态下均表现出最佳的室温强度。
