PNNL

Abstract

A thorough understanding of the processing-structure property relationships of additively manufactured (AM) parts is critical for applications. Detailed microstructural, tensile, axial fatigue, and Charpy impact properties were evaluated of AM nickel alloy 625 builds produced by laser-beam powder-bed-fusion, with powders manufactured using different atomization conditions. Post-heat treatment resulted in a recrystallized, equiaxed grain structure that eliminated anisotropy in tensile properties between the build and transverse directions. Axial fatigue properties along the build direction were similar to design handbook wrought fatigue data. Furthermore, Charpy impact energy values were superior to wrought data in the hot-rolled condition. Fractography was performed on failed fatigue and Charpy specimens and the fracture surfaces of Charpy specimens were found to be covered predominantly by fine dimples.