7075铝合金脉冲变极性等离子弧焊接头的双级时效行为  

Two-stage aging behavior of pulse variable polarity plasma arc welding joint of 7075 aluminum alloy

作　　者：李国伟[1,2] 梁亚红 陈芙蓉[1,2] 韩永全 LI Guo-wei;LIANG Ya-hong;CHEN Fu-rong;HAN Yong-quan(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;Inner Mongolia Key Laboratory of Light Metal Materials,Hohhot 010051,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,呼和浩特010051 [2]内蒙古自治区轻金属材料重点实验室,呼和浩特010051

出　　处：《材料工程》2020年第2期140-147,共8页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(51665044);内蒙古自治区草原英才资助项目(CYYC5033);内蒙古自治区重大基础研究开放课题资助(ZJYK2015);内蒙古自治区高等学校科学研究项目(NJZY20072);内蒙古工业大学科学研究项目(ZZ201807,BS201922)

摘　　要：通过力学性能、电导率测试和TEM分析,对10 mm厚7075铝合金脉冲变极性等离子弧焊(pulse variable polarity plasma arc welding,PVPPAW)接头的双级时效行为特征进行研究,并确定了较为合理的双级时效工艺。结果表明:7075铝合金PVPPAW接头的抗拉强度随着终时效温度的升高和终时效时间的延长先增大后减小。经160℃,12 h终时效处理后的接头抗拉强度为545.1 MPa,比焊态时提高了37%。此时接头的电导率为27.9%IACS,抗应力腐蚀性能有所提高。焊缝中心主要强化相为η′相和η相,随着终时效温度的升高和终时效时间的延长,晶内与晶界的析出相逐渐长大和粗化,晶界的无沉淀析出带变宽。Two-stage aging behavior of pulse variable polarity plasma arc welding(PVPPAW)joint of 7075 aluminum alloy with thickness of 10 mm was studied by mechanical properties,electrical conductivity test and TEM analysis,and the reasonable two-stage aging process was determined.Results show that the tensile strength of 7075 aluminum alloy PVPPAW joints increases first and then decreases with the increase of second-step aging temperature and time.After second-step aging with 160℃/12 h,the tensile strength of joint is 545.1 MPa,which increases by 37%than as-weld.And the conductivity is 27.9%IACS,the resistance to stress corrosion is improved than as-weld.The main strengthening phases of the weld center areη′phase andηphase.The precipitated phases of grain interior and grain boundary grow up and become coarsened gradually,and the precipitated free zone in the grain boundary becomes wider with the increase of the second-step aging temperature and time.

关 键 词：7075铝合金 脉冲变极性等离子弧焊 双级时效 显微组织 性能 

分 类 号：TG456.2[金属学及工艺—焊接]