不同循环加载条件下镁合金AZ21腐蚀疲劳行为  

Corrosion fatigue properties of AZ21 Mg alloy under different cyclic loading conditions

作　　者：龙飞[1] 程维姝 陈刚[3] 崔云[4] LONG Fei;CHENG Weishu;CHEN Gang;CUI Yun(Institute of Machinery Manufacturing Technology, China Academy of Engineering Physics, Mianyang 621900, China;Beiyang National Distillation Technology Co. , Ltd. , Tianjin 300072, China;School of Chemical Engineering and Technology, Tianjin Uni- versity, Tianjin 300150, China;Ren＇ai College, Tianjin University, Tianjin 301636, China)

机构地区：[1]中国工程物理研究院机械制造工艺研究所,四川绵阳621900 [2]北洋国家精馏技术工程发展有限公司,天津300072 [3]天津大学化工学院,天津300150 [4]天津大学仁爱学院,天津301636

出　　处：《哈尔滨工程大学学报》2017年第10期1635-1641,共7页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(11172202);教育部新世纪优秀人才项目(NCET-13-0400)

摘　　要：镁合金作为结构件承受多轴复杂载荷,其失效形式多为多轴疲劳失效。为澄清复杂载荷下镁合金的腐蚀疲劳行为,本文在磷酸盐缓冲溶液(phosphate buffered solution,PBS)中对镁合金AZ21的多轴循环疲劳行为进行了研究,通过分析镁合金应力应变滞环及峰值应变的演化规律,揭示了不同加载路径和腐蚀环境耦合作用下材料的变形主导机制。腐蚀环境中的疲劳试验结果表明,在相同等效应力幅下,非比例加载路径下镁合金AZ21在PBS腐蚀环境中的寿命较单轴拉伸、纯扭路径显著降低。采用Basquin公式预测了镁合金AZ21在复杂载荷和PBS腐蚀环境耦合作用下的疲劳寿命。通过将路径非比例度的概念引入对Basquin公式进行修正,可合理预测相同加载幅值下圆形路径和菱形路径作用时镁合金AZ21在PBS腐蚀环境中的疲劳寿命。Magnesium （Mg） alloy is widely used for engineering structural components, and it normally bears complicated multiaxial loads. Muhiaxial fatigue failure is the main failure mode of Mg alloy. To clarify the corrosion fatigue behavior of Mg alloy under complex loads, the paper studies the multiaxial cyclic fatigue behavior of Mg alloy AZ21 in a phosphate-buffered solution （PBS）. The dominant deformation mechanisms were revealed under the cou- pling effect of different loading paths and corrosive environments by analyzing the evolution law of the stress and strain hysteresis and peak strain of Mg alloy AZ21. Results of the fatigue test conducted in the corrosive environ- ment show that, under the same and equivalent stress amplitude, the life of Mg alloy AZ21 in PBS corrosive envi- ronment and at the non-proportional loading path is apparently lower than that under the conditions of uniaxial tension and purely torsional path. Basquin formula was used to predict the fatigue life of the Mg alloy AZ21 under the coupling effect of complex loads and PBS corrosive environment. Through the introduction of a non-proportionality path factor into Basquin formula for amendment, the fatigue life of Mg alloy AZ21 in PBS corrosive environment can be reasonably forecast under the same loads, circular path, and rhombus path.

关 键 词：镁合金 多轴疲劳失效 腐蚀疲劳 多轴棘轮 非比例加载 寿命预测 复杂载荷 磷酸盐缓冲溶液 

分 类 号：U674.21[交通运输工程—船舶及航道工程]