Microstructural evolution and mechanical properties of TIG welded superalloy GH625
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- 作者：Yu-li GU ; bluebee4646@163.com" class="auth_mail" title="E-mail the corresponding author ; Chun-hu TAO ; Zhen-wei WEI ; Chang-kui LIU
- 关键词：nickel-based wrought superalloy ; TIG welding ; microstructure ; microhardness ; tensile property
- 刊名：Transactions of Nonferrous Metals Society of China
- 出版年：2016
- 出版时间：January 2016
- 年：2016
- 卷：26
- 期：1
- 页码：100-106
- 全文大小：3045 K
文摘
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.