Experimental investigation of a Portevin-Le Chatelier band in Ni‒Co-based superalloys in relation to γʹ precipitates at 500 ℃. (15th July 2020)

• Record Type: Journal Article
• Authors: Liu, Yanke; Cai, Yulong; Tian, Chenggang; Zhang, Guoliang; Han, Guoming; Fu, Shihua; Cui, Chuanyong; Zhang, Qingchuan
• Is Part Of: Journal of materials science & technology. Volume 49(2020)
• Page Start: 35
• Page End: 41
• Publication Date: 2020-07-15
• Subjects: γ′ Precipitate -- Ni‒Co-based superalloy -- Dynamic strain aging -- Portevin–Le Chatelier effect -- Digital image correlation; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2020.02.001
• Languages: English
• ISSNs: 1005-0302

Abstract

Abstract: The macroscopically localized deformation behaviors of Ni–Co-based superalloys with different γ′ precipitate content were investigated at 500 °C and 1 × 10 −4 s −1 via an in situ method namely, digital image correlation (DIC). The DIC results showed that the serrated flow of the stress–strain curves was accompanied by localized deformation of the specimens. The fracture morphology was characterized mainly by transgranular fracture with numerous dimples in the low γ′ content alloy, and intergranular fracture with large fracture section in the high γ′ content alloy. The Portevin–Le Chatelier (PLC) effect occurred in the investigated Ni–Co-based superalloys. Furthermore, the localized deformation of the high γ′ content alloy was more severe than that of the low γ′ content alloy, and the band width was slightly larger. Moreover, for the first-time ever, a special propagation feature, namely ±60° zigzag bands characterized by head-to-tail connections, was observed in the high γ′ content alloy.