高温预析出后7055铝合金局部腐蚀性能和时效硬化  

Influence of High-Temperature Pre-Precipitation on Local Corrosion Behaviors and Ageing Harden of 7055 Aluminum Alloy

作　　者：黄兰萍[1] 陈康华[1] 李松[1] 宋蛟[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《稀有金属材料与工程》2007年第9期1628-1633,共6页Rare Metal Materials and Engineering

基　　金：教育部新世纪优秀人才支持计划(NCET-04-0752);国家重点基础研究发展规划项目(2005CB623704);国家自然科学基金项目(50471057)

摘　　要：研究了高温预析出对Al-Zn-Mg-Cu系7055合金的应力腐蚀、晶间腐蚀和剥蚀行为以及时效硬化的影响,并通过对预析出/时效组织的透射电镜观察,阐述了预析出对7055合金各种腐蚀行为和时效硬化的影响。组织观察及腐蚀性能和力学性能测试结果表明:高温预析出处理可使7055合金抗应力腐蚀性能得到明显改善,合金应力腐蚀开裂界限应力强度因子KISCC由7.4MPa·m1/2提高至9.8MPa·m1/2,合金抗拉强度仍能保持在680MPa左右。经高温预析出处理后的7055合金晶间腐蚀、剥蚀敏感性降低,7055合金的剥蚀等级由EC降为EA-。同时,高温预析出处理使晶界析出相粗化显著、离散度增大,晶界平衡析出相的Cu含量为60.18at%,且晶界析出相Cu含量提高。The influence of high-temperature pre-precipitation on stress corrosion cracking, intergranular corrosion, exfoliation corrosion behaviors and age hardening of 7055 Al-Zn-Mg-Cu aluminum alloy has been investigated in this paper. The transmission electron microscopy have shown that the high-temperature pre-precipitation could enhance the discontinuity of grain boundary precipitates and make Cu content of grain-boundary precipitates reach to 60.18at%. The stress corrosion cracking resistance of 7055 alloys could be improved with non-deteriorated strength and plasticity via the high-temperature pre-precipitation. After pre-precipitating stress intensity factor Kxscc of 7055 alloy raised from 7.4 MPa·m^1/2 to 9.8 MPa·m^1/2. 7055 aluminum alloy with high-temperature pre-precipitation has good intergranular corrosion and exfoliation corrosion resistance property.

关 键 词：7055铝合金 高温预析出 剥落腐蚀 晶间腐蚀 应力腐蚀断裂 

分 类 号：TG172.9[金属学及工艺—金属表面处理]