外加应力对高Cu/Mg比Al-Cu-Mg合金沉淀动力学及析出相形态的影响  

Effect of External Stress on Kinetics of Precipitation and Morphologies of Precipitates in Al-Cu-Mg Alloy with High Cu/Mg Ratio

作　　者：杨培勇[1] 郑子樵[1] 胥福顺[2] 李世晨[1] 李剑[1] 周明[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]云南铝业股份有限公司,云南昆明650502

出　　处：《稀有金属》2006年第3期324-328,共5页Chinese Journal of Rare Metals

基　　金：国家自然科学基金(59971066);高等学校博士学科点专项科研基金(20040533022)资助项目

摘　　要：采用电阻测量和透射电镜观察研究了外加应力对Al-3.88Cu和Al-4.80Cu-0.56Mg合金时效动力学及析出相形态的影响,结果表明:外加应力延缓了Al-Cu二元合金时效过程中电阻率的降低,即阻碍了θ″和θ′相的析出,但是却加速了α+θ相区Al-Cu-Mg三元合金时效过程中电阻率的降低,即促进了合金中第二相的析出,出现这种现象的原因与Al-Cu-Mg合金中相θ′和S′相的竞争析出有关。Al-Cu-Mg合金中θ′相和S′相的析出过程受应力的影响不同,外加应力通过改变竞争析出过程中θ′相和S′相的力量对比,阻碍了θ′相的析出,从而促进了S′相的析出,导致应力时效态合金电阻率降低的速度和程度大于无应力时效合金。Effect of external stress on kinetics of precipitation and morphologies of precipitates in A1-3.88Cu and A1-4.80Cu-0.56Mg alloys was investigated by electrical resistivity measurement and transmission electron microscopy. The results indicate that external stress retards the reduction of electrical resistivity in A1-Cu alloys while accelerates the reduction in A1-Cu-Mg alloys, which is caused by the competitive precipitation between θ′ and S′ phases. The influences ofstress on the precipitation of θ′ and S′ phases are different. By altering the precipitation equilibrium between θ′ and S′ phases, the external stress retards the precipitation of θ＂ and phase θ′, thereby accelerates the precipitation of S′ phase. As a result, the electrical resistivity reduction of stress aged A1-Cu-Mg alloy is faster and deeper than the electrical resistivity reduction of stress-free one.

关 键 词：铝合金 应力时效 相对电阻率 竞争析出 形核与长大 

分 类 号：TG111.5[金属学及工艺—物理冶金]