Microstructural evolution and mechanical properties of TIG welded superalloy GH625  

氩弧焊接GH625高温合金的显微组织演变与力学性能（英文）

作　　者：顾玉丽[1] 陶春虎[1] 魏振伟[1] 刘昌奎[1] 

机构地区：[1]中航工业北京航空材料研究院航空材料检测与评价北京市重点实验室,北京100095

出　　处：《Transactions of Nonferrous Metals Society of China》2016年第1期100-106,共7页中国有色金属学报（英文版）

摘　　要：The tungsten inert gas welding（TIG） technique was employed to weld the nickel-based wrought superalloy GH625, and the microstructures, element distribution, grain boundary character and mechanical properties of the welded joint were investigated systematically. The results indicated that the welded seam was of austenite dendrite crystal structure and no obvious heat affected zone（HAZ） was observed. A number of precipitated δ phases with homogeneous distribution were observed in the interdendritic region of the weld fusion zone. The abnormal phenomenon observed in the weld fusion zone of GH625, i.e., higher hardness and larger grain size compared with the base metal, may be attributed to the precipitated δ phase in the weld fusion zone. The higher tensile strength in the base metal was mainly attributed to the presence of more contents of fine grains and twin boundaries, while the lower elongation in the welded joint was mainly owing to the precipitated δ phase.采用钨极氩弧焊接工艺对镍基变形高温合金GH625进行焊接。系统研究焊接接头的显微组织、元素分布、晶界特征和力学性能。结果表明:焊缝组织为奥氏体树枝晶结构,未见明显的热影响区,焊接熔合区的枝晶间区域均匀分布着大量的δ相。与母材相比,焊接熔合区同时具备较高的硬度和较大的晶粒,这可能与焊接熔合区的δ析出相有关。母材较高的强度主要归因于较多的细小晶粒和孪晶界,而焊接接头较低的伸长率可能是由于δ相。

关 键 词：nickel-based wrought superalloy TIG welding microstructure MICROHARDNESS tensile property 

分 类 号：TG444.74[金属学及工艺—焊接]