About this Abstract |
Meeting |
2020 AWS Professional Program
|
Symposium
|
2020 AWS Professional Program
|
Presentation Title |
Mitigation of Liquid Metal Embrittlement in Galvannealed AHSS Welds Using High Entropy Alloy Filler |
Author(s) |
Abdelrahman Abdelmotagaly, Benjamin Schneiderman , Zhenzhen Yu, Jianxun Hu |
On-Site Speaker (Planned) |
Abdelrahman Abdelmotagaly |
Abstract Scope |
Liquid metal embrittlement (LME) phenomenon can take place in resistance spot welding (RSW) of galvannealed advanced high strength steels for automotive applications. During welding, Zn melts at much lower temperature than steel (approximately 1000 ºC difference), which satisfies the conditions of LME cracking as liquid Zn becomes in contact with the solid steel sheet under tensile stress induced by RSW electrodes. This work aims to mitigate LME by implementing high entropy alloy (HEA) foils to capture Zn from the weld region and prevent Zn diffusion and/or penetration into grain boundaries of steel substrate.
The HEA composition was designed based on thermodynamic and kinetic calculations using a filtration code written in MATLAB coupled with high-throughput CALPHAD simulation, which predict the solidification behavior of HEA filler itself and the interface reactions between the HEA and galvannealed AHSS. Experimental work validated the proposed novel solution by comparing RSW with and without the HEA foils. By applying thin HEA foils to the outer surfaces of the spot welds, preferential diffusion of Zn into the HEA foil rather than the grain boundaries of DP980 steel substrate was observed in EDS mapping results, while in conventional RSW samples with the same welding parameters but without HEA foils multiple Zn-enriched cracks were observed around the weld shoulder region. Furthermore, tensile shear test showed a 23% increase in fracture load for samples with HEA foils than that of conventional welds. Hardness mapping results showed that HEA foil did not introduce any noticeable change in hardness profile of the RSW joints. |
Proceedings Inclusion? |
Definite: Other |