热处理对Al-Si-Cu-Mg铸造铝合金低周疲劳行为的影响  

Influence of Heat Treatment on Low-Cycle Fatigue Behavior of Al-Si-Cu-Mg Alloy

作　　者：李锋[1] 陈巧[1] 车欣[1] 陈立佳[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,辽宁沈阳110870

出　　处：《铸造》2012年第3期300-303,共4页Foundry

摘　　要：为了确定固溶处理及固溶+时效处理对金属型铸造Al-Si-Cu-Mg铝合金低周疲劳行为的影响,在不同外加总应变幅下进行应变控制的室温低周疲劳试验。结果表明:金属型铸造Al-Si-Cu-Mg铝合金可表现为循环应变硬化、循环应变软化和循环稳定;固溶处理及固溶+时效处理可以有效地提高金属型铸造Al-Si-Cu-Mg铝合金的疲劳寿命,且固溶处理对疲劳寿命提高的幅度更大;铸态及固溶态Al-Si-Cu-Mg铝合金的弹性应变幅、塑性应变幅与疲劳断裂时的载荷反向周次之间分别呈直线关系,固溶+时效态Al-Si-Cu-Mg铝合金的弹性应变幅与疲劳断裂时的载荷反向周次之间呈直线关系,但其塑性应变幅与疲劳断裂时的载荷反向周次之间呈双线性关系;不同处理状态的铸造Al-Si-Cu-Mg铝合金的循环应力幅与塑性应变幅之间呈线性关系。In order to determine the influence of solid-solution and solid-solution plus aging treatments on low-cycle fatigue behavior of permanent-mold cast Al-Si-Cu-Mg alloy, the strain controlled low-cycle fatigue tests were performed at room temperature and different total strain amplitudes. The experimental results show that the permanent-mold cast Al-Si-Cu-Mg alloy exhibits the cyclic strain hardening, softening and stability. The solid-solution and solid-solution plus aging treatments can effectively enhance the fatigue lives of the permanent-mold cast Al-Si-Cu-Mg alloy, and the solid-solution treatment has more significant in enhancing the fatigue lives of the alloy. A single-slope linear relationship between plastic and elastic strain amplitudes as well as reversals to failure is observed for both as-cast and solid-solution treated Al-Si-Cu-Mg alloys. For the permanent-mold cast A1-Si-Cu-Mg alloy subjected to solid-solution plus aging treatment, the relationship between elastic strain amplitude and reversals to failure also shows linear behavior, but a bilinear relationship between plastic strain amplitude and reversals to failure is noted. Moreover, the relationship between cyclic stress amplitude and plastic strain amplitude exhibits linear behavior.

关 键 词：铝合金 热处理 低周疲劳 疲劳寿命 循环应力响应 

分 类 号：TG166.3[金属学及工艺—热处理]