Grain refinement and element partitioning in ultrasound-assisted wire and electron beam additively manufactured Udimet 500 nickel superalloy
A. V. Vorontsov, Anna Zykova, Y. V. Kushnarev, V. R. Utyaganova, Evgeny Moskvichev, D. A. Gurianov, K. S. Osipovich, Е. А. Колубаев, Н. Л. Савченко, S. Yu. Tarasov
Abstract
Ultrasonic-assisted wire and electron beam additive manufacturing (WEBAM) of Udimet 500 alloy wall was carried out. This ultrasound with power levels 0, 150, 300, and 600 W was transmitted via a sonotrode secured on a stainless steel substrate and allowed reducing the degree of anisotropy . The as-built samples were composed of γ-solid solution and both coarse (>100 nm) and fine (<100 nm) γ′-particles along with (Ti,Mo)C and TiC carbides dispersed in the γ-matrix. Sonication resulted in refining the primary γ-grains, eliminating the cubic texture component, and transformation of TiC carbides into (Ti,Mo)C ones. Element partitioning among matrix and both coarse and fine γ′-particles was observed that resulted in increasing the positive lattice γ/γ′ misfit with the ultrasound power increased. Tensile strength improved with the ultrasound power while microhardness numbers remained constant as measured along the building direction. Sonication at 600 W allowed obtaining excellent balance between strength and plasticity in the WEBAM-built Udimet 500 due to improved homogeneity and γ/γ′- grain refinement.