Microstructures and dislocations in the stressed AZ91D magnesium alloys
Microstructures and dislocations in the stressed AZ91D magnesium alloys
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DOI：
10.1016/s0921-5093(02)00413-6
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发表时间：
2003-03
期刊：
影响因子：
6.4
通讯作者：
Rongming Wang;A. Eliezer;E. Gutman
中科院分区：
文献类型：
--
作者：
Rongming Wang;A. Eliezer;E. Gutman
采用透射电镜、高分辨透射电镜和能谱分析等方法研究了压铸AZ 91 D镁合金及应力状态下的微观组织和位错排列。合金中除了主要的α-Mg和β-Mg 17 Al 12相外，还发现并研究了Al 8 Mn 5和Mg 5Al相。首次在AZ 91 D合金中发现了位错塞积现象。它们被限制在滑移面中，并靠着晶界堆积。位错塞积随变形量的增加而增加，直到约2.1%，然后即使变形到更高程度也几乎保持不变。发现AZ 91 D镁合金中的位错堆积有利于合金的抗应力腐蚀开裂能力，从而有利于合金的力学性能。在所有情况下，位错网络被发现增加与变形。在变形的AZ 91 D镁合金中，β-Mg 17 Al 12相和基体中也发现了位错网络。
The microstructures and the dislocation arrangements in the die cast AZ91D magnesium alloy as well as the stressed alloys have been investigated using transmission electron microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray (EDX) analysis. Besides the dominant α-Mg and β-Mg17Al12phases, Al8Mn5and Mg5Al phases have also been found and studied in the alloy. Dislocation pile-ups have been found in the stressed AZ91D alloys for the first time. They are confined in the slip planes and piled up against the grain boundaries. The dislocation pile-ups increase with deformation till about 2.1% and then remain almost identical even deformed to higher degree. The dislocations pile-ups in the AZ91D magnesium alloy are found to be beneficial to the resistance to stress corrosion cracking of the alloy, and thereby beneficial to the mechanical properties of the alloy. Dislocation networks are found to increase with deformation in all cases. The dislocation networks have also been found in the β-Mg17Al12phase as well as in the matrix in the deformed AZ91D magnesium alloys.