固溶处理对2E12铝合金组织及疲劳断裂行为的影响

通过对2E12铝合金进行493 ℃/20 min和503℃/20 min固溶处理,研究固溶处理对2E12合金室温拉伸及疲劳性能的影响.采用X线衍射分析、扫描电镜和金相分析对合金组织及疲劳断口进行观察.研究结果表明:提高固溶处理温度对合金拉伸性能影响不大,但可明显减少合金中残留相(Al2Cu,A12CuMg)的含量；经503 ℃/20 min处理后合金的拉伸强度较经493℃/20 min处理后合金的拉伸强度略有提高,但其疲劳寿命延长约20％；合金中残留相在疲劳过程中容易开裂形成微小二次裂纹,在主裂纹扩展过程中起到桥接作用,从而加速疲劳裂纹扩展,降低合金疲劳性能.

Effect of solution treatment on fatigue behavior of 2E12 aluminum alloy

The effects of solid solution treatment(493 ℃/20 min and 503 ℃/20 min) on fatigue fracture and room mechanical properties of 2E12 aluminum alloy were investigated.Observation of microstructure and fatigue fracture was presented by means of X-ray diffraction,scanning electron microscope(SEM) and metallographical analysis.The results show that increasing the heating temperature has no obvious effect on the tensile properties of 2E12 aluminum alloy.The number of residual phases(Al2Cu,Al2CuMg) decreases during solid solution treatment.For 493 ℃/20 min and 503 ℃/20 min solution treated alloys,both alloys have the similar mechanical properties,but the latter has a better fatigue life with 20% improvement.The residual phases are easily dehisced to form micro-cracks during the fatigue process,offering more pathes for macro-crack propagation to reduce the fatigue properties.