预处理对Al-Mg-Si合金蠕变时效行为及力学性能的影响

Effects of Pre-Treatments on Creep Aging Behaviors and Mechanical Properties of Al-Mg-Si Alloy

本文采用了蠕变曲线测试、室温拉伸及透射电镜等方法研究了不同预处理工艺(120℃/3 h预时效、5%预拉伸)对Al-Mg-Si合金在75 MPa/175℃条件下蠕变时效行为及其最终力学性能的影响。结果表明,引入预处理工艺能降低Al-Mg-Si合金的稳态蠕变速率和蠕变应变量;经7 h蠕变时效后,分别引入预时效和预拉伸后,试样的屈服强度分别较未作预处理的试样分别提高了16.2%、29.5%。透射电镜显微组织研究结果表明,预处理既能提高Al-Mg-Si合金中析出相的分布密度,同时又能消减合金在蠕变时效过程中产生的应力位向效应。本文的研究结果可为进一步提升Al-Mg-Si合金强度的工艺开发提供参考。

Creep curves tests, tensile tests and transmission electron microscope (TEM) were conducted to study the effects of pre-treatments (120˚C/3 h pre-aging, 5% pre-stretching) on the creep behaviors and mechanical properties of Al-Mg-Si alloy under condition of 75 MPa applied load and aging temperature 175˚C in this paper. The results showed that the pre-treatments decreased the steady creep rate and creep strain of Al-Mg-Si alloy. After 7 h creep aging, the yield strengths of the pre-aged sample and pre-stretched sample were increased by 16.2%, 29.5%, respectively, when compared with the as-quenched sample. The results of TEM showed that the pre-treatments can increase the distribution density of the precipitates of Al-Mg-Si alloy, and can eliminate the stress orientation effect of the alloy during creep aging as well. The results of this paper can provide fa-vorable guidance for developing process to further improve the strength of Al-Mg-Si alloys.