低频电磁铸造Al-Zn-Mg-Cu合金微观组织与性能  

The Microstructure and Properties of Low Frequency Electromagnetic Casting Al-Zn-Mg-Cu Alloy

作　　者：曾渝[1] 尹志民[1] 潘青林[1] 朱远志[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《金属热处理》2003年第10期8-11,共4页Heat Treatment of Metals

基　　金：国家"8 6 3"高新技术研究项目 (2 0 0 1AA332 0 30 )

摘　　要：采用拉伸性能及电导率测试、透射电镜观察、低应变拉伸试验等手段 ,研究了不同时效工艺对低频电磁铸造Al Zn Mg Cu合金组织和性能的影响。发现合金的T6态峰值时效制度为 12 0℃× 4 8h ,T6处理可使合金强度达到峰值 ,但抗应力腐蚀性能差 ;T73处理后合金强度下降了 5 %～ 6 % ,抗应力腐蚀性能大幅度提高 ;而RRA时效 (回归再时效 )处理基本保持了T6态的强度 ,且抗应力腐蚀性能接近T73态。微观组织分析表明 ,不同时效制度下合金性能的差异主要是由晶内和晶界析出相的大小、形貌及其分布状态决定的。T73和RRA时效处理改善了合金晶界特性 ,有助于阻止氢脆、减缓晶界阳极溶解速度 。The effects of various ageing treatments on the microstructure and properties of a new type low frequency electromagnetic casting Al Zn Mg Cu alloy were investigated by using tensile properties and electric conductivity test,TEM observations and low strain tensile.The results show that at the peak aging treatment of the alloy of 120℃×48h,the T6 treatment can have high strength but poor SCCR;with T73 treatment the strength decreased 5%～6% but good SCCR,while RRA treatment can maintain the strength as T6 treatment and obtain good SCCR close to T73.Analysis of microstructure shows that the different properties of alloy undertook different aging treatment are determined by the size,morphology and distribution of precipitations in grains and grain boundaries.T73 and RRA treatment improve the grain boundary character,which is help to inhibit hydrogen embrittlement and decrease anodic dissolution rate,then to improve the SCCR of the alloy.

关 键 词：时效 Al—Zn—Mg—Cu合金 回归再时效 微观组织 抗应力腐蚀性能 

分 类 号：TG166.3[金属学及工艺—热处理]