摘要
Rapid-cooling friction-stir-welding(FSW)was used to join AZ31B magnesium alloy plates of 6 mm in thickness.The microstructure and mechanical properties in thickness direction were carefully investigated with electron backscattered diffractometer,and transmission electron microscope.The obtained results showed that ultrafine grains with high dislocation density were obtained in the top region of the weld due to liquid CO2 cooling.A large number of{1012}twins and second-phase particles were also induced in these refined grains.The basal texture intensity was significantly reduced due to the appearance of{1012}twins.The top region showed the higher strength and elongation compared with the bottom region,and the welding efficiency reached 93%.This work provided a simple and efficient strategy for manufacturing a gradient structure in the FSW Mg alloy joint.
采用电子背散射衍射仪和透射电子显微镜研究快速冷却对6 mm厚AZ31B镁合金搅拌摩擦焊缝厚度方向的显微组织和力学性能的影响。结果表明,液态二氧化碳冷却可促进焊缝顶部形成具有高位错密度、大量{1012}孪晶和第二相颗粒的细晶结构。{1012}孪晶使焊缝顶部区域的基面织构显著降低。接头顶部区域的强度和断后伸长率较底部区域均明显提高,焊接效率可达93%。这为在镁合金搅拌摩擦焊接头中制备梯度结构提供一种简单有效的方法。
基金
Project(51805145)supported by the National Natural Science Foundation of China
Project(CJ20200076)supported by the Changzhou Science and Technology Program,China
Project(B200202229)supported by the Fundamental Research Funds for the Central Universities of China
Project(2020102941517)supported by Hohai University Undergraduate Innovation and Entrepreneurship Training Program,China。
