不同循环加载条件下镁合金AZ21腐蚀疲劳行为

发布时间：2018-01-19 10:37

本文关键词： 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　出处：《哈尔滨工程大学学报》2017年10期 　论文类型：期刊论文

【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。
[Abstract]:Magnesium alloy as a structural part is subjected to multiaxial complex load, and its failure form is mostly multiaxial fatigue failure. In order to clarify the corrosion fatigue behavior of magnesium alloy under complex load. The multiaxial cyclic fatigue behavior of magnesium alloy AZ21 was studied in phosphate buffer solution phosphate buffered solution. By analyzing the evolution law of stress strain hysteresis and peak strain of magnesium alloy, the dominant deformation mechanism of magnesium alloy under the coupling action of different loading paths and corrosion environment is revealed. The fatigue test results in corrosion environment show that. Under the same equivalent stress amplitude, the life of magnesium alloy AZ21 under non-proportional loading path is longer than that of uniaxial tensile in PBS corrosion environment. The fatigue life of magnesium alloy AZ21 under the coupling action of complex load and PBS corrosion environment was predicted by Basquin formula. The concept of non-proportional degree of path was introduced to B. The asquin formula is modified. The fatigue life of magnesium alloy AZ21 in PBS corrosion environment can be reasonably predicted under the action of circular path and diamond path under the same loading amplitude.
【作者单位】：中国工程物理研究院机械制造工艺研究所;北洋国家精馏技术工程发展有限公司;天津大学化工学院;天津大学仁爱学院;
【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)
【分类号】：TG178
【正文快照】： 目前,镁合金在航空、航天、电子、汽车、生物等领域得到广泛应用[1-3],已成为替代钢铁、铝合金和工程塑料以实现轻量化的理想材料之一[4-5]。由于镁合金的化学性质活泼,导致其腐蚀抗力较低,极大限制了它的应用。当腐蚀液中含有氯离子时,腐蚀导致材料的疲劳性能急剧下降[6-7]。

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