Effects of post-weld heat treatment on microstructure and mechanical properties of Hastelloy N superalloy welds. (June 2019)

• Record Type: Journal Article
• Authors: Wang, Wanxia; Jiang, Li; Li, Chaowen; Leng, Bin; Ye, Xiang-Xi; Liu, Renduo; Chen, Shuangjian; Yu, Kun; Li, Zhijun; Zhou, Xingtai
• Is Part Of: Materials today communications. Volume 19(2019)
• Page Start: 230
• Page End: 237
• Publication Date: 2019-06
• Subjects: Post-weld heat treatment (PWHT) -- Carbide evolution -- Hastelloy N superalloy -- Welding -- Mechanical properties; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2019.02.004
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: The effects of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of Hastelloy N superalloy welds were systematically investigated. Eutectic-like M6 C carbides and nano-sized M2 C carbides were observed in the interdendritic region of the as-welded specimens, with finer granular M6 C carbides precipitating at the dendrite boundaries. With the increase in the PWHT temperature, the nano-sized M2 C carbides dissolved, while the M6 C carbides at the dendrite boundaries coarsened. When the PWHT temperature increased to 950 °C, the nano-sized M2 C carbides completely disappeared. Consequently, the weld with the PWHT at higher temperatures exhibited lower micro-hardness, lower yield strength, and higher elongation. In particular, the elongation increased by 63% after applying the PWHT at 950 °C for 6 h.