Elemental Effects on Weld Cracking Susceptibility in AlxCoCrCuyFeNi High-Entropy Alloy

Alexander C. Martin, João Pedro Oliveira, Carolin Fink

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Weld solidification and weldability of AlxCoCrCuyFeNi high-entropy alloys (HEA) were characterized as a function of Al and Cu molar ratio in the alloy composition. Autogenous gas tungsten arc welding (GTAW) was performed on the as-melted ingots. Fusion zone and heat-affected zone microstructures were investigated using optical and electron microscopy, and compared to thermodynamic CALPHAD-based calculations. Weld cracking susceptibility was compared to cast pin tear test (CPTT) results. It was found that strong Cu segregation on solidification promotes hot cracking in fusion welds on AlCoCrCuyFeNi alloys (y > 0.1). Cu-rich liquid forms during the final stages of solidification and facilitates solidification cracking in the fusion zone. The Cu-rich interdendritic readily remelts during reheating and promotes liquation cracking in the heat-affected zone. The cracking mechanisms in the welds change to brittle intergranular cracking in low and no Cu alloy compositions due to a high-hardness BCC microstructure (> 500 HV). Lowering the Al molar ratio in AlxCoCrCu0.1FeNi alloys (x ≤ 0.5) mitigates brittle cracking by promoting FCC solidification structure.

Original languageEnglish
Pages (from-to)778-787
Number of pages10
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume51
Issue number2
DOIs
Publication statusPublished - 1 Feb 2020

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