Design and development of a high-performance Ni-based superalloy WSU 150 for additive manufacturing

Abstract

This research proposes a design and development strategy of a new nickel-based superalloy for additive manufacturing. A new Ni-based superalloy has been developed by the application of the combinatorial alloy development technique coupled with CALPHAD based solidification modeling by effectively suppressing the precipitation kinetics. The suppression of precipitation during processing paved a way for prevention of cracks during deposition. The new alloy “WSU 150″ revealed excellent room temperature mechanical properties with a yield strength of 867 MPa, an ultimate tensile strength of 1188 MPa, and an elongation of 27.9% in the as-deposited condition. The mechanical properties of the heat-treated alloy were improved significantly to 1114 MPa yield strength, 1396 MPa ultimate tensile strength, and an elongation of 16.1%. Improvement in the mechanical properties is attributed to the additional precipitation and coarsening of γʹ and carbides during heat-treatment. Microstructural investigation of the alloy revealed spherical γʹ with a rippled size distribution from the center to the interdendritic region. The average size of the γʹ particles in the as-deposited condition was found to be around 48 nm in the interdendritic region. Heat-treatment promoted the coarsening of γʹ which is explained in the paper.