Precipitation of metastable phases and its effect on electrical resistivity of Al-0.96Mg_2Si alloy during aging  

Al-0.96Mg_2Si合金时效过程亚稳相析出行为及其对合金电阻率的影响(英文)

作　　者：崔立新 刘振兴[2] 赵晓光 唐建国[2] 刘科 刘星兴[2] 钱晨[2] 

机构地区：[1]山东创新合金研究院,邹平256200 [2]中南大学材料科学与工程学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第7期2266-2274,共9页中国有色金属学报（英文版）

基　　金：Project(51105139)supported by the National Natural Science Foundation of China;Project(2010CB731706)supported by the National Basic Research Program of China

摘　　要：The precipitation behavior and its influence on the electrical resistivity of the Al-0.96Mg2Si alloy during aging were investigated with in-situ resistivity measurement and transmission electron microscopy （TEM）. The precipitates of the peak aged alloy include both β＂ and if, but the amount ratio of β＂ to β＂ varies with the aging temperature and time increasing. The precipitates during aging at 175 ℃ are dominated by needle-like β＂ phases （including pre-β＂ phase）, the size of which increases with the time prolonging, but does not increase substantially after further aging. The evolution of electrical conductivity is directly related to such microstructural evolution. However, the hardness of the alloy stays at the peak value for a long term. When the alloy is aged at 195 ℃, the ratio of β＂ to β＇ becomes the main factor to influence relative resistivity （Ap） value. The higher the temperature is, the smaller the ratio is, and the faster the Ap value decreases. Moreover, the hardness peak drops with the decrease of the ratio. With the size and distribution parameters measured from TEM images, a semi-quantitative relationship between precipitates and the electrical resistivity was established.采用原位电阻率测试和透射电镜观察研究Al-0.96Mg2Si合金的析出行为及其对电阻率的影响。发现峰值时效的析出相包括β″和β′,而他们的比例随着时效温度和时间的改变而变化。合金在175°C峰值时效内的析出相主要是针状β″相(也包括pre-β″)。这些析出相会随着时效时间的延长而长大,但是进一步延长时效时间至超出峰值时效时间后,析出相的尺寸变化并不显著。合金电导率的变化规律与之类似。合金硬度峰值时效后,继续时效很长一段时间硬度变化都不显著。由于温度是影响β″/β′比的主要因素,因此时效温度也是影响电阻率的主要因素。时效温度越高β″/β′的比值越小,ρ下降的速度就越快。硬度也随着该比值的减小而降低。通过对透射电镜照片分析获得析出相的分布参数,建立了析出相与电阻率之间的半定量关系式。

关 键 词：Al-Mg-Si alloy metastable phases electrical resistivity AGING PRECIPITATE 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG156.92[金属学及工艺—金属材料]