Effect of Heat Treatment on Microstructure and Mechanical Properties of Mg-5Zn-1Mn Alloy Tube
Effect of Heat Treatment on Microstructure and Mechanical Properties of Mg-5Zn-1Mn Alloy Tube
复制标题
热处理对Mg-5Zn-1Mn合金管显微组织和力学性能的影响
DOI：
10.3390/met10030301
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发表时间：
2020-03-01
期刊：
影响因子：
2.9
通讯作者：
Ouyang, Xiaoping
中科院分区：
文献类型：
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作者：
Li, Lianhui;Cao, Hongshuai;Ouyang, Xiaoping
采用光学显微镜（OM）、X射线衍射仪（XRD）、扫描电镜（SEM）、透射电镜（TEM）、单轴拉伸试验和电化学测试等方法，研究了热处理对挤压态Mg-5 Zn-1 Mn（ZM 51）合金管材组织、力学性能和电化学性能的影响。结果表明：铸态组织为典型的枝晶组织，主要由α-Mg和Mg 7Zn 3共晶化合物组成。均匀化处理后，大部分Mg 7Zn 3共晶相溶解在镁基体中。在挤压过程中，ZM 51合金发生了完全的动态再结晶，并具有良好的延伸率，达到21.4%。T6，特别是T4 +双时效处理，可显著提高挤压态管材的力学性能。显微组织分析表明，细小弥散的MgZn 2相的析出强化是强度提高的主要原因。挤压态管材的断口形貌主要由韧窝和解理面组成，为典型的韧性断裂。时效态合金管材的断裂方式属于解理断裂。此外，电化学测试结果表明，固溶处理后的ZM 51合金管材具有最好的耐腐蚀性能。耐蚀性的提高主要是由于显微组织的均匀性和较低的相体积分数。
The effects of heat treatment on the microstructure, mechanical properties and electrochemical property of the as-extruded Mg-5Zn-1Mn (ZM51) alloy tube are investigated by optical microstructure (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electrical microscope (TEM), uniaxial tensile test, and electrochemical test. The results show that the as-cast structure is a typical dendritic structure, mainly composed of α-Mg and Mg7Zn3 eutectic compounds. After homogenization, most of Mg7Zn3 eutectic phases are dissolved in the Mg matrix. During the extrusion process, the ZM51 alloy has undergone complete dynamic recrystallization and has a good elongation, reaching 21.4%. T6, especially T4 + double aging treatment, can significantly improve the mechanical properties of the as-extruded tube. The microstructure reveals that the precipitation strengthening of the finely dispersed MgZn2 precipitates is the main reason for the strength increase. The fracture micromorphology of the as-extruded tube is mainly composed of dimples and cleavage facets, which is a typical ductile fracture. The fracture mode of the as-aged alloy tubes belongs to cleavage fracture. In addition, the electrochemical test results show the solution-treated ZM51 alloy tube has the best corrosion resistance. The improvement of corrosion resistance is mainly due to the microstructure uniformity and low phase volume fraction.