时效对纳米TiC/Ti细化Al-Zn-Mg-Cu合金耐蚀性的影响  

Influence of Aging on Corrosion Resistance of Nano TiC/Ti Refined Al-Zn-Mg-Cu Alloy

作　　者：江萍萍[1] 程婧璠[1] 赵炳怡 柳波[1] 蔡启舟[1] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室

出　　处：《特种铸造及有色合金》2017年第5期534-538,共5页Special Casting & Nonferrous Alloys

基　　金：科技重大专项课题资助项目(2012ZX04010-081)

摘　　要：采用浸泡腐蚀、极化曲线和应力腐蚀等方法研究时效对纳米TiC/Ti细化Al-Zn-Mg-Cu合金耐蚀性的影响。结果表明,峰时效态和过时效态细化合金在3.5%的NaCl溶液中浸泡192h,腐蚀速率分别为0.756 5mm/a和0.361 3mm/a。峰时效态化合金在NaCl和NaCl+H_2O_2溶液中的应力断裂时间分别为72.2h和50.1h;过时效态为221.2h和80.8h,过时效态合金抗应力腐蚀性能高于峰时效态的。峰时效添加TiC/Ti细化合金后晶界较宽的PFZ(无沉淀析出带)降低其耐蚀性,过时效态晶界不连续且粗大的η相以及较窄的PFZ使合金耐蚀性提高。Effects of aging on corrosion behavior of a novel nano TiC/Ti refiner refined Al-Zn-Mg-Cu alloy were investigated by means of soaking corrosion,polarization curve and stress crack corrosion.The results indicate that after soaked in 3.5% NaCl solution for 192 h,the corrosion rate of peak-aged and over-aged Al-Zn-Mg-Cu alloy refined with TiC/Ti reach 0.756 5mm/a and 0.361 3mm/a respectively.The fracture time of stress crack corrosion are 72.2h and 50.1h with the peak-aged alloy refined with TiC/Ti at NaCl and NaCl＋H2O2 solution,respectively,while at over-aged,they are 221.2h and 80.8h,respectively.The resistance of stress crack corrosion at over-aged is the higher than that of ones at peak-aged.The wider PFZ can decrease significantly the corrosion resistance of alloy refined with TiC/Ti at peak-aged,however,at over-aged,the coarse and discontinuous phase preciphated from grain boundary and the narrow PFZ can improve the corrosion resistance.

关 键 词：AL-ZN-MG-CU合金 纳米TiC/Ti细化剂 时效 极化曲线 应力腐蚀 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG166.3[金属学及工艺—金属材料]