摘要
通过力学性能测试、XRD物相分析、拉伸断口形貌分析、剥落腐蚀性能评估等试验,研究了时效应力对7A04铝合金二级时效力学及剥落腐蚀性能的影响。结果表明:时效应力为100~300MPa时,7A04铝合金的强度和硬度有所增加;当时效应力为200MPa时,合金的Rm、Rp0.2和布氏硬度分别达652.3MPa、588.5MPa和178HB,相比于无应力二级时效分别提高了4.47%、3.94%和5.95%,而塑性变化不大;随时效应力的增大,时效试样组织中MgZn2析出相含量增加,并且其断裂方式发生改变;适当的时效应力可降低7A04铝合金剥落腐蚀敏感性,时效应力为200MPa时,合金抗剥落腐蚀性能最优,抗剥落腐蚀等级为EA。
Effects of aging stress on the mechanical properties and exfoliation corrosion resistance of 7A04 aluminum alloy with two-stage aging were investigated by mechanical properties test, XRD analysis, tensile fracture surface analysis and exfoliation corrosion evaluation. The results indicated that the strength and hardness of 7A04 aluminum alloy increased with the aging stress of 100~300 MPa. Compared with no stress-aging condition, the tensile strength, yield strength and hardness of 7A04 aluminum alloy reached 652.3 MPa, 588.5 MPa and 178HB after aged with stress of 200 MPa, increased by 4.47%, 3.94% and 5.95% respectively, but the change of the elongation is insignificant. Additionally, with the increase of aging stress, the content of MgZn 2 precipitates in the microstructure of the alloy increased, and the fracture mode of the alloy also changed. The suitable aging stress can reduce the exfoliation corrosion sensitivity of 7A04 aluminum alloy, and the alloy has the best corrosion resistance with the aging stress of 200 MPa, which reached the level of EA.
作者
李虎
赵君文
王超群
郭安
李恒奎
戴光泽
LI Hu;ZHAO Junwen;WANG Chaoqun;GUO An;LI Hengkui;DAI Guangze(School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031;Yangzhou Fengze Rail Technologies Co. Ltd. ,Yangzhou 225200;CRRC Qingdao Sifang Co. Ltd. ,Qingdao 266111)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第12期2025-2029,共5页
Materials Reports
基金
国家科技支撑计划项目(2015BAG12B01)~~
关键词
7A04铝合金
时效应力
二级时效
剥落腐蚀性能
7A04 aluminum alloy
aging stress
two-stage aging
exfoliation corrosion resistance
