Impact of Arc-Based Welding on the Microstructure Evolution and Mechanical Properties in Newly Developed Cr_29.7Co_29.7Ni_35.4Al₄Ti_1.2 Multi-Principal Element Alloy

Multi-principal element alloys (MPEAs) have been subjected to extensive research due to their promising potential for numerous applications. Up to now, most of the existing research has been focused on unraveling the microstructural evolution and describing the exceptional performance of these alloys when exposed to demanding environments. Nevertheless, it is especially important to understand their processability so that these advanced engineering alloys can be considered for real-life applications where conventional manufacturing processes, such as welding, are widely used. Herein, gas tungsten arc welding (GTAW) is used for similar welding of a recently developed precipitation-hardened Cr_29.7Co_29.7Ni_35.4Al₄Ti_1.2 MPEA. The microstructural evolution and resulting mechanical properties are characterized by combining optical and electron microscopy, synchrotron X-ray diffraction, microhardness mapping, and tensile testing. The different microstructure features across the welded joint are correlated to the weld thermal cycle and resulting local mechanical properties. Overall, the Cr_29.7Co_29.7Ni_35.4Al₄Ti_1.2 MPEA exhibits excellent weldability and mechanical properties, reaching a tensile strength of ≈750 MPa and a fracture strain of ≈33% during tensile tests, making this alloy viable for structural applications. The innovative aspect of this work includes the expansion of the current understanding on the physical metallurgy of MPEAs, as well as the examination of this particular MPEA's processability.