Wu Pengfei, Deng Yunlai, Fan Shitong, Ji Hua, Zhang Xinming
School of Materials Science and Engineering, Central South University, Changsha 410083, China.
Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Central, Central South University, Changsha 410083, China.
Materials (Basel). 2018 Jul 4;11(7):1132. doi: 10.3390/ma11071132.
In this paper, the microstructure of friction stir welded between the Al⁻Li⁻Cu alloy and the Al⁻Zn⁻Mg⁻Cu alloy was studied using optical microscope(OM), electronic backscattered diffraction (EBSD), SEM, and TEM. The hardness profile revealed that the range of heat affect zone for the Al⁻Zn⁻Mg⁻Cu alloy was slightly wider than the Al⁻Li⁻Cu alloy when they suffered from the thermal transient. Additionally, the characterization of precipitates inside the different zones was obviously different, which corresponded to the microhardness distribution profile. At the periphery of the kissing line, the Al⁻Li⁻Cu and the Al⁻Zn⁻Mg⁻Cu alloys mutually diffused during the weld process. The magnesium element in the Al⁻Zn⁻Mg⁻Cu alloy diffused into the Al⁻Li⁻Cu alloy. But the copper and zinc had no change because of the low diffusion coefficient in aluminum. The heat affected zone of the Al⁻Zn⁻Mg⁻Cu alloy showed a higher corrosion susceptibility immersed into the corrosion environment, and the Al⁻Li⁻Cu alloy did not show severe corrosion.
本文采用光学显微镜（OM）、电子背散射衍射（EBSD）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了Al⁻Li⁻Cu合金与Al⁻Zn⁻Mg⁻Cu合金搅拌摩擦焊接的微观结构。硬度分布表明，Al⁻Zn⁻Mg⁻Cu合金和Al⁻Li⁻Cu合金在经历热瞬态时，Al⁻Zn⁻Mg⁻Cu合金的热影响区范围略宽于Al⁻Li⁻Cu合金。此外，不同区域内析出相的特征明显不同，这与显微硬度分布曲线相对应。在结合线周边，Al⁻Li⁻Cu合金与Al⁻Zn⁻Mg⁻Cu合金在焊接过程中相互扩散。Al⁻Zn⁻Mg⁻Cu合金中的镁元素扩散到Al⁻Li⁻Cu合金中。但由于铜和锌在铝中的扩散系数较低，其含量没有变化。Al⁻Zn⁻Mg⁻Cu合金的热影响区在浸入腐蚀环境时表现出较高的腐蚀敏感性，而Al⁻Li⁻Cu合金未表现出严重腐蚀。
