(1. 華北水利水電大學(xué) 機(jī)械學(xué)院，鄭州 450045；
2. 大連理工大學(xué) 材料科學(xué)與工程學(xué)院，大連 116024)
摘 要: 采用慢應(yīng)變速率拉伸試驗(yàn)(SSRT)和透射電鏡(TEM)測(cè)試分析方法研究了熱矯正次數(shù)對(duì)7N01-T5鋁合金應(yīng)力腐蝕敏感性的影響。結(jié)果表明：隨著熱矯正次數(shù)的增加，7N01-T5鋁合金應(yīng)力腐蝕敏感性增加。原因主要在于晶界析出相的轉(zhuǎn)變以及溶質(zhì)元素Zn和Mg從基體向晶界的不斷擴(kuò)散。基于非平衡偏聚理論可知，三次熱矯正的等效恒溫時(shí)間小于臨界時(shí)間tc。因此，隨著熱矯正次數(shù)的增加，晶界處Zn和Mg元素含量逐漸增加，增大了晶界與基體間的腐蝕電位差，使7N01-T5鋁合金應(yīng)力腐蝕敏感性增加。
關(guān)鍵字: 慢應(yīng)變速率拉伸試驗(yàn)；熱矯正；應(yīng)力腐蝕開(kāi)裂；非平衡偏聚；鋁合金
（1. School of Mechanical Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, China;
2. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China）
Abstract:Stress corrosion cracking behavior of 7N01-T5 aluminum alloy was investigated using slow strain rate test (SSRT) and transmission electron microscope (TEM). The results show that the stress corrosion cracking susceptibility increases with increasing the times in heat straightening. The main reason lies in the transformation of intergranular precipitation and the diffusion of solute elements Zn and Mg from matrix to grain boundary. The effective time of non-equilibrium segregation of solute elements Zn and Mg during three times of heat straightening is less than the critical time, tc, according to the theory of non-equilibrium segregation. Consequently, the contents of solute elements Zn and Mg at grain boundaries gradually increase with increasing the times in heat straightening, which leads to an increase in corrosion potential difference between the grain boundary and its surrounding substrate, thus results in the increase of stress corrosion cracking susceptibility of 7N01-T5 aluminum alloy.
Key words: slow strain rate test; heat straightening; stress corrosion cracking; non-equilibrium segregation; aluminum alloy
