Xie Jilin, Ma Yingche, Ou Meiqiong, Xing Weiwei, Zhang Long, Liu Kui
Institute of Metal Research, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016, China.
School of Materials Science and Engineering, University of Science and Technology of China, No. 96 Jinzhai Road, Hefei 230026, China.
Materials (Basel). 2018 Oct 22;11(10):2065. doi: 10.3390/ma11102065.
Two kinds of filler materials were used to join dissimilar alloys between a new cast superalloy K4750 and Hastelloy X by tungsten gas arc welding (GTAW). The segregation behavior, interfacial microstructure and mechanical properties of the dissimilar joints were evaluated. The results show that both filler materials can be used to obtain sound dissimilar joints successfully. Microstructural observation show that no obvious cracking is observed in the joints achieved by both filler materials. The segregation extent of various elements in Hastelloy X weld metal is more severe than that in the K4750 weld metal. No unmixed zones were observed at the interfaces. Transition areas with the chemical compositions various between the K4750 alloy and the Hastelloy X alloy were found at the joint interfaces. The maximum width of the transition area between the K4750 weld metal and Hastelloy X base metal is smaller than that between the Hastelloy X weld metal and K4750 base metal. The ultimate tensile strength and yield strength of the joints with Hastelloy X filler material are slightly higher than those with K4750 filler material, however, the K4750 filler material results in a higher total elongation and fusion zone microhardness than those with Hastelloy X filler material. Both dissimilar joints fractured with a ductile feature which exhibits tearing edges and dimples. Hastelloy X filler material is suggested to be more suitable for joining of K4750 superalloy and Hastelloy X dissimilar metals in terms of obtaining superior comprehensive mechanical properties.
采用两种填充材料，通过钨极气体保护电弧焊（GTAW）对新型铸造高温合金K4750与哈氏合金X之间的异种合金进行连接。对异种接头的偏析行为、界面微观组织和力学性能进行了评估。结果表明，两种填充材料均可成功获得质量良好的异种接头。微观组织观察表明，两种填充材料所获得的接头均未观察到明显裂纹。哈氏合金X焊缝金属中各元素的偏析程度比K4750焊缝金属中的更严重。在界面处未观察到未混合区。在接头界面处发现了K4750合金与哈氏合金X合金之间化学成分不同的过渡区。K4750焊缝金属与哈氏合金X母材之间过渡区的最大宽度小于哈氏合金X焊缝金属与K4750母材之间过渡区的最大宽度。采用哈氏合金X填充材料的接头的抗拉强度和屈服强度略高于采用K4750填充材料的接头，然而，K4750填充材料导致接头的总伸长率和熔合区显微硬度高于采用哈氏合金X填充材料的接头。两种异种接头均呈韧性断裂特征，表现为撕裂边缘和韧窝。就获得优异的综合力学性能而言，建议哈氏合金X填充材料更适合于K4750高温合金与哈氏合金X异种金属的连接。
