【摘要】 研究了固溶、时效处理对挤压变形AZ81镁合金在疲劳加载条件下的循环应力响应行为、循环应力-应变行为、应变疲劳参数以及疲劳寿命的影响。结果表明,热处理可导致挤压变形AZ81镁合金的循环应力幅有所降低;固溶处理和固溶+时效处理可有效提高挤压变形AZ81镁合金在较高总应变幅下的疲劳寿命;不同处理状态的挤压变形AZ81镁合金的弹性应变幅、塑性应变幅与疲劳断裂时的载荷反向周次之间的关系可分别用Basquin和Coffin-Manson公式描述;挤压态、时效态以及固溶+时效态的挤压变形AZ81镁合金的循环应力幅与塑性应变幅之间的关系可用单斜率直线描述,而固溶态的挤压变形AZ81镁合金的循环应力幅与塑性应变幅之间则呈现双斜率线性行为。更多还原

【Abstract】 The influence of solid solution and(or) aging treatment on the cyclic stress response behavior,cyclic stress-strain behavior,strain fatigue parameters and fatigue life of the extruded AZ81 magnesium alloy under fatigue loading was investigated.The results reveal that the heat treatment can lead to a decrease of cyclic stress amplitude for the extruded AZ81 alloy under same total strain amplitude.Both solid solution treatment and solid solution plus aging treatment enhance the fatigue lives of the extruded AZ81 alloy at higher total strain amplitudes.For the extruded AZ81 alloy heat treated with different temper,the relation between elastic strain amplitude,plastic strain amplitude and reversals to failure can be described by the Coffin-Manson and Basquin equations,respectively.For the as-extruded AZ81 alloy as well as the extruded AZ81 alloy after aging and solid solution plus aging treatment,the relationship between cyclic stress amplitude and plastic strain amplitude can be described by a exponent equation.However,the relation between the cyclic stress amplitude and plastic strain amplitude exhibits a bilinear behavior for the extruded AZ81 alloy after solid solution treatment in a log-log diagram.更多还原