(1. 桂林航天工業(yè)學(xué)院 實(shí)踐教學(xué)部，桂林 541004； 2. 中南大學(xué) 粉末冶金研究院，長(zhǎng)沙 410083； 3. 成都京東方光電科技有限公司，成都 611731)
摘 要: 采用金相、硬度、電導(dǎo)率、剝落腐蝕、電化學(xué)腐蝕以及透射電鏡(TEM)觀察等分析測(cè)試方法研究焊后熱處理對(duì)Al-Zn-Mg合金組織與性能的影響。結(jié)果表明：Al-Zn-Mg合金焊接接頭固溶區(qū)的硬度和耐腐蝕性能隨焊后熱處理時(shí)效時(shí)間的延長(zhǎng)和溫度的提高而提升。自然時(shí)效4 d+(130 ℃, 24 h)和自然時(shí)效150 d+(150 ℃, 2 h)兩種焊后熱處理工藝較佳：經(jīng)自然時(shí)效4 d+(130 ℃, 24 h)處理后，合金固溶區(qū)最大硬度由82.5HV提高至123HV，最大電導(dǎo)率由34%IACS提高至35.8%IACS，剝蝕等級(jí)提升至EA；經(jīng)自然時(shí)效150 d+(150 ℃, 2 h)處理后，合金固溶區(qū)最大硬度提高至110HV，最大電導(dǎo)率至34.7%IACS，剝蝕等級(jí)提升至N。合金焊接接頭固溶區(qū)硬度與耐腐蝕性能提升的主要原因是焊后時(shí)效熱處理促進(jìn)焊接固溶區(qū)晶內(nèi)析出相粗化，彌散分布，且晶界析出相呈不連續(xù)分布狀。
關(guān)鍵字: Al-Zn-Mg合金；焊后熱處理；時(shí)效；硬度；腐蝕性能
（1. Practical Teaching Department, Guilin University of Aerospace Technology, Guilin 541004, China; 2. Institute of Powder Metallurgy, Central South University, Changsha 410083, China; 3. Chengdu Beijing Oriental Electronics Optoelectronics Technology Co., Ltd., Chengdu 611731, China）
Abstract:The effects of post-welding heat treatment on microstructure and properties of Al-Zn-Mg alloy welded joint were studied by optical microstructure, hardness, conductivity, exfoliation corrosion testing, electrochemical corrosion testing and transmission electron microscopy (TEM) testing. The results show that the hardness and corrosion resistance of welded joint at solid solution zone of Al-Zn-Mg alloy increase with post-welding aging time and temperature increasing. Two kinds of optimum post-welding heat treatment to Al-Zn-Mg alloy are natural aging for 4 d+artificial aging at (130 ℃, 24 h) and natural aging for 150 d+artificial aging at (150 ℃, 2 h). The maximum hardness of welded joint at solid solution zone of Al-Zn-Mg alloy increases from 82.5HV to 123HV, the maximum conductivity increases from 34%IACS to 35.8%IACS and the denudation level reaches to EA after natural aging 4 d+artificial aging at (130 ℃, 24 h) treatment. The maximum hardness of welded joint at solid solution zone of Al-Zn-Mg alloy increases from 82.5HV to 110HV, the maximum conductivity increase from 34%IACS to 34.7%IACS and the denudation level reaches up to N after natural aging for 150 d+artificial aging at (150 ℃, 2 h) treatment. The reason why aging treatment can improve the hardness and corrosion resistance of welded joint at solid solution zone of Al-Zn-Mg alloy is that the intragranular precipitate phase are coarsening and dispersion distribution, also the grain boundary precipitate phase distribution are discontinuous.
Key words: Al-Zn-Mg alloy; post-welding heat treatment; aging; hardness; corrosion property
