Effect of local texture and precipitation on the ductility dip cracking of ERNiCrFe-7A Ni-based overlay. (15th November 2016)

• Record Type: Journal Article
• Authors: Wei, Xiao; Xu, Mengjia; Wang, Qingzhao; Zhang, Maolong; Liu, Weihua; Xu, Jijin; Chen, Junmei; Lu, Hao; Yu, Chun
• Is Part Of: Materials & design. Volume 110(2016)
• Page Start: 90
• Page End: 98
• Publication Date: 2016-11-15
• Subjects: Local texture -- Nickel-based alloy -- Ductility dip cracking -- Grain boundary misorientation -- M23C6; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.07.130
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: The multi-pass ERNiCrFe-7A overlay depositions, produced by cold wire feed (CWF) or hot wire feed (HWF) gas tungsten arc welding (GTAW) process with typical parameters, were employed to investigate the effects of different micro-characteristics on ductility-dip cracking (DDC) susceptibility. The results show that, the HWF-produced deposit exhibited the texture with larger quantity of 〈001〉 oriented grains in the pass region (away from the fusion line), while the CWF-produced deposit was weakly textured with increased crystallographic misorientation for the higher heat input per unit volume. Crystal misorientation also increased in the interpass region (near the fusion line) of both the overlays. Results of strain-to-fracture (STF) tests indicated that the overall DDC resistance in the deposit CWF was lower than that in the deposit HWF. And the interpass region exhibited higher DDC susceptibility than the pass region. The intergranular cracking is found to be triggered by the strain accumulation between differently oriented grains. Meanwhile, both the over 30° misorientation angle and melting of Cr-rich M23 C6 carbides reduced the grain boundary (GB) strength and promoted the cracking. Therefore, the DDC resistance would be increased by decreasing the GBs those have misorientation angles over 30°, as well as the carbides distributed on the GBs. Graphical abstract: Highlights: Textures with different orientation were generated in different region of the Ni-based overlays. The DDC susceptibility increased with the increase of crystal misorientation in the local texture. DDC was observed to preferentially initiate at high misorientation angle GBs between differently oriented grains. Grain boundary carbides were observed to melt over 1000 °C and partly promote the DDC.