【轻有色合金】氩气处理对AZ91镁合金高温力学性能的影响

赵正任¹  贾征^{1, 2} 王彤² 高源¹ 郭锦鹏¹  胡天润¹ 柳鑫¹

(1.沈阳大学机械工程学院； 2.东北大学材料电磁过程研究教育部重点实验室)

摘要:研究了氩气处理对AZ91镁合金高温力学性能的影响。结果表明，经过氩气处理后，每100 g熔体中的氢含量从未处理的14.8 cm³ 降低至7.3 cm³，除气率高达50.7%；在20、100、175、250、325和400 ℃对合金分别进行拉伸试验，发现除气对合金抗拉强度和屈服强度的影响随温度升高而逐渐减小，但对伸长率的影响正好相反。在温度低于250 ℃时除气，合金强度显著提高，伸长率变化不明显，除气对在高温(250~325 ℃)拉伸时强度影响不大，但明显提高了镁合金的伸长率，另外，应变硬化指数(n)值相差不大(分别为0.04和0.03)。

关键词：AZ91镁合金；除气；高温力学性能；应变硬化指数

中图分类号:TG146.22   文献标志码    A

DOI:10.15980/j.tzzz.2020.04.022

Effects of Ar Dehydrogenation on Mechanical Properties of AZ91 Alloy at High Temperature

Zhao Zhengren¹, Jia Zheng^{1, 2} , Wang Tong², Gao Yuan¹, Guo Jinpeng¹, Hu Tianrun¹, Liu Xin¹

(1.College of Mechanical Engineering, Shenyang University; 2.Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education, Northeastern University)

Abstract:Effects of Ar dehydrogenation on mechanical properties of AZ91 alloy at high temperature were investigated. The results indicate that the hydrogen content can be reduced from 14.8 cm³/100 g to 7.3 cm³/100 g and the degassing efficiency reaches to 50.7%. The effects of degassing on tensile and yield strength of the alloy are decreased with the increase in temperature in AZ91 alloy at 20, 100, 175, 250, 325 and 400 ℃,respectively, while that on elongation is opposite to that on strength. The strength of AZ91 alloy after degassing is improved obviously when the temperature is lower than 250 ℃ with little difference on elongation. Degassing has little effect on strength of alloy at the temperature from 250 ℃ to 325 ℃.However, the elongation of alloy is improved obviously and the strain hardening exponents are basically the same (0.04 and 0.03, respectively).

Key Words: AZ91 Alloy, Degassing, High Temperature Mechanical Properties, Strain Hardening Exponent