Electron beam powder bed fusion enables crack-free, high-strength and sufficiently ductile chemically complex intermetallic alloys

Abstract

ABSTRACTIn contrast to traditional intermetallics that are difficult to process and prone to cracking during additive manufacturing, our work demonstrates the successful fabrication of crack-free, high-performance CCIMAs via electron beam powder bed fusion (EBPBF). The microstructures of CCIMAs (NiCoFeAlTiB) fabricated by EBPBF are remarkably complex, exhibiting a multiphase composition where the disordered FCC phase forms the matrix interleaved with L12-ordered intermetallic phase. The unique combination of ordered lattices and high-entropy disordered phases, tuned by optimised EBPBF processing, imparts exceptional mechanical properties with a high tensile strength (∼1 GPa) and a sufficient ductility (∼11%). It is found that additional minor HCP and L21 precipitates can also effectively slow down and block the crack extension. This work demonstrates a pathway for crack-free fabrication of CCIMAs with tailored microstructures using EBPBF which may provide new insights and manufacturing strategies to unlock the potential of these advanced intermetallic alloys.

Keywords

• Intermetallic alloys
• electron beam powder bed fusion
• precipitate phase