Liquid metal embrittlement in laser lap joining of TWIP and medium-manganese TRIP steel: The role of stress and grain boundaries
- Centre for Advanced Materials Joining, Department of Mechanical & Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada)
- Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)
- International Zinc Association, Durham, NC 27713 (United States)
Highlights: • This work shows liquid metal embrittlement in externally loaded laser lap welding. • Results confirmed a direct relation between external load and LME susceptibility. • TWIP steel showed a higher LME susceptibility compared to medium-Mn TRIP steel. • Results indicated stress-assisted diffusion of Zn into austenite grain boundaries. • High angle grain and Σ3 twinning boundaries play major role in Zn penetration. - Abstract: High-Manganese austenite-containing steels with superior combination of strength and ductility have shown potential for enhancement of passenger safety and body-in-white (BIW) weight reduction. Even though Zn-coated austenitic steels have improved corrosion resistance, they are highly susceptible to liquid metal embrittlement (LME) during welding. The present work is aimed to address LME susceptibility during restrained laser lap joining of high-Mn twinning induced plasticity (TWIP) and medium-Mn transformation induced plasticity (MMn-TRIP) steels. Electron probe micro-analysis (EPMA) results showed that stress-assisted diffusion of Zn into the austenite grain boundaries and further liquid Zn formation by a peritectic reaction lead to grain boundary decohesion. Electron backscatter diffraction (EBSD) results demonstrated that high angle and special grain boundaries are prone to Zn-penetration within the heat-affected-zone (HAZ). Additionally, LME sensitivity was observed to be highly dependent on the magnitude of applied stress.
- OSTI ID:
- 22805885
- Journal Information:
- Materials Characterization, Vol. 145; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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