预变形对2E12铝合金时效析出过程的影响

通过DSC热分析、显微硬度测试、透射电镜分析等研究了预变形对2E12铝合金时效析出过程的影响。结果表明：2E12铝合金表现为双阶段时效硬化特征，预变形降低了合金时效第1阶段硬化效果，提高了合金峰时效硬度，缩短了峰时效时间；随预变形量的增加，合金峰时效硬度增大，峰时效时间提前。增加预变形量使合金中析出的板条状S相更为细小、弥散。预变形引入位错对沉淀析出有利，位错环纯刃型位错为S相析出提供有利位置，促进球状S相形核。预变形产生位错结构有利于I型S相析出,并延缓II型S相析出

Effect of Pre-deformation on Aging Precipitation Process of 2E12 Aluminum Alloy

The effect of pre-deformation on the aging precipitation process of 2E12 aluminum alloy was investigated by DSC analysis, microhardness test and transmission electron microscope (TEM). The results show that the peak aging of 2E12 alloy exhibits two distinct stages. Pre-deformation weakens the hardening effect of the first aging stage, enhances the peak aging hardness and accelerates the aging process. The peak aging hardness increases and peak aging time decreases with more pre-deformation amount. Increase in pre-deformation degree also leads to finer and more dispersive S-lath in 2E12 alloy. The dislocations introduced by the pre-deformation provide preferential sites for the heterogeneous nucleation of S phase. The edge dislocation sites in dislocation loops are beneficial for nucleation of spherical S phase. Pre-deformation accelerates the precipitation of Type I S phase and delays the precipitation of Type II S phase