论文部分内容阅读
对A1-Zn-Mg-Cu合金进行了单级和双级时效处理,测试了不同状态下的显微硬度,利用光学显微镜和透射电镜观察了显微组织。结果表明:120℃单级时效合金具有很明显的强化效应,时效4 h硬度达到193 HV,随后趋于平缓,时效时间延长至24 h,硬度增幅不大;120℃单级时效处理后,合金晶内析出相细小弥散,硬化效果较好,晶界析出相呈链状分布;120℃×4 h+160℃×12 h双级时效后,硬化效果更优,晶界析出相呈断续状,并且晶界附近出现无析出带。
The Al-Zn-Mg-Cu alloys were subjected to single-stage and double-stage aging treatments. The microhardness under different conditions was tested. The microstructure was observed by optical microscope and transmission electron microscope. The results show that the single-stage aged alloy at 120 ℃ has the obvious strengthening effect, the hardness reaches to 193 HV at 4 h after aging, then tends to be gentle, and the aging time prolongs to 24 h with little increase in hardness. After single-stage aging at 120 ℃, The precipitated phase is fine and the hardening effect is better. The precipitated phase in the grain boundary is chain-like. After two-stage aging at 120 ℃ × 4 h + 160 ℃ × 12 h, the hardening effect is better and the precipitated phase is discontinuous , And there is no precipitation zone around grain boundary.