摘要
本文通过调控高温(200℃)回归时间,系统研究回归时效对喷射成形Al-Zn-Mg-Cu合金析出相演变、力学性能及腐蚀性能的影响。结果表明:双级时效处理使合金晶内和晶界形成大量纳米级析出相,其中晶界连续分布的析出相导致晶间腐蚀深度达139μm。经过高温回归时效处理,短时回归(≤10 min)依赖基体溶质原子再分配,在细化晶界沉淀相尺寸的同时使合金晶内析出高密度纳米相,并维持合金高强度(抗拉强度803 MPa),使晶间腐蚀深度降低至73μm;长时回归(≥20 min)使晶内小尺寸析出相溶解、晶内大尺寸析出相持续粗化,同时促使晶界析出相球化且间距增大。晶界断续析出相与较宽的无沉淀析出带(38 nm)阻断腐蚀路径,合金晶间最大腐蚀深度降低至25μm,抗拉强度降至约730 MPa。上述结果表明,通过精准调控回归时效工艺窗口,可实现纳米沉淀相分布特征与无沉淀析出带宽度的协同调控,解决高强铝合金强度-耐蚀性协同优化难题。
The influence of retrogression time at 200℃on precipitate evolution,mechanical properties and corrosion behavior of spray-formed Al-Zn-Mg-Cu alloy were systematically investigated.The results show that,during double aging,the alloy develops abundant nanoprecipitates in both intragranular and grain boundary regions.The continuous grain boundary precipitates lead to severe intergranular corrosion with a maximum depth of 139μm.After high temperature retrogression treatment,the short-term retrogression(≤10 min)facilitates solute redistribution,the high-density intragranular nanoprecipitates retain while refining grain boundary precipitates,and the high tensile strength(803 MPa)is achieved,the intergranular corrosion depth reduces to 73μm.Prolonged retrogression(≥20 min)induces the dissolution of fine intragranular precipitates and the continuous coarsening larger precipitates,simultaneously promoting the spheroidization of grain boundary precipitates and the increase of sapce.The discontinuous grain boundary precipitates combined with widened precipitate-free zones(38 nm)effectively block the corrosion paths,which reducing the maximum intergranular corrosion depth to 25μm and the tensile strength about 730 MPa.These results demonstrate that precise control of retrogression duration enables synergistic optimization of nanoprecipitate distribution and PFZ width,resolving the strength-corrosion resistance trade-off in high-strength aluminum alloys.
作者
孙宜琳
徐严谨
曾元松
韩宝帅
陈明璐
冯诺
胡猜
SUN Yilin;XU Yanjin;ZENG Yuansong;HAN Baoshuai;CHEN Minglu;FENG Nuo;HU Cai(AVIC Manufacturing Technology Institute,Institute of Metallic Materials Technology,Beijing 100024,China)
出处
《中国有色金属学报》
2025年第9期2883-2895,共13页
The Chinese Journal of Nonferrous Metals
基金
国家重点研发计划资助项目(2023YFB3710805)。
作者简介
通信作者:徐严谨,研究员,博士,电话:010-85701427,E-mail:xuyj_avic@aliyun.com。
