Welding of High Entropy Alloys-A Review

Area of Science:

• Materials Science
• Metallurgy
• Welding Engineering

Background:

• High-entropy alloys (HEAs) offer unique properties like thermal stability and strength.
• Welding is critical for HEA applications, but joint properties vary significantly with methods.
• Understanding weldment microstructure and properties is vital for service life, especially in corrosive environments.

Purpose of the Study:

• To review recent research on welding high-entropy alloys (HEAs).
• To compare microstructures and properties of fusion zones (FZ) and heat-affected zones (HAZ) across different welding techniques.
• To analyze structure-property relationships and identify future research directions.

Main Methods:

• Systematic review of recent experimental work on HEA welding.
• Summarization of experimental details: sample preparation, size, and welding conditions.
• Comparison of microstructural features (element distribution, phase fraction, lattice constants) and mechanical properties (hardness, strength, ductility).

Main Results:

• Weldability of HEAs depends on composition and welding method.
• Arc and laser welding of AlCoCrFeNi HEAs yield lower hardness and strength.
• Friction stir welding results in higher FZ hardness and comparable/higher joint strength with retained ductility.

Conclusions:

• Welding significantly impacts HEA microstructure and properties.
• Friction stir welding demonstrates superior performance for HEA joining compared to arc and laser methods.
• Further research is needed to optimize welding processes and understand structure-property correlations for diverse HEA systems.