Effect of extrusion parameters on microstructure and mechanical properties of ZK30 Mg Alloy
Effect of extrusion parameters on microstructure and mechanical properties of ZK30 Mg Alloy
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DOI：
10.1179/174328408x276224
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发表时间：
2008-04
影响因子：
1.8
通讯作者：
K. S. Nair;M. Mittal;R. Sikand;A. Gupta
中科院分区：
文献类型：
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作者：
K. S. Nair;M. Mittal;R. Sikand;A. Gupta
镁合金是最轻的结构金属材料，在航空航天领域有着广泛的应用前景。但由于其加工性差、强度中等、耐腐蚀性差等原因，限制了其应用。ZK 30镁合金（Mg-3·0 Zn-0·5 Zr（wt-%））由于晶粒细小，比常规Mg-Al-Zn基变形合金具有更好的强度和加工性能。在本研究中，将该合金的均质化坯料在各种温度和冲压速度下挤压成方管，以确定均匀变形和最佳机械性能的制度。在所有研究条件下，材料均表现出动态重结晶。挤压温度的升高改善了变形的均匀性，但温度的进一步升高（>400°C）导致异常晶粒生长。还发现增加冲压速度可增强均匀变形，但进一步增加冲压速度（>8 mm s-1）会导致绝热加热和流动局部化。根据本研究的结果，最佳工艺参数制度，最终确定均匀的变形和最佳的机械性能。
Mg alloys are the lightest structural metallic materials, and are very attractive for aerospace applications. But their applications are limited owing to their poor workability, moderate strength and poor corrosion resistance. ZK30 Mg alloy (Mg–3·0Zn–0·5Zr (wt-%)) shows better strength and workability due to the presence of fine grains than conventional Mg–Al–Zn base wrought alloys. In the present study homogenised billets of this alloy were extruded into square tubes at various temperatures and ram speeds to determine the regime of uniform deformation and best mechanical properties. Material exhibited dynamic recrystallisation under all the conditions studied. Increase in the extrusion temperature improves the homogeneity of deformation but further increase in temperature (>400°C) causes abnormal grain growth. Increase in ram speed is also found to enhance uniform deformation but further increase in ram speed (>8 mm s−1) causes adiabatic heating and flow localisation. Based on the findings of the present study, an optimum process parameter regime was finalised for homogeneous deformation and best mechanical properties.