Repeatability of Additively Manufactured Precipitation Hardened 17% Chromium - 4% Nickel Stainless Steel

Abstract

Research in additive manufacturing (AM) as a viable process for next-generation marine vessels has identified benefits of increased corrosion resistance and strength in precipitation hardened (PH) stainless steel alloyed components. For AM to reliably meet Naval manufacturing needs, the linkages of processing parameters, geometry, microstructure, and material performance must be defined. Alloyed 17% Chromium - 4% Nickel (17-4 PH) thin fin structures of three thicknesses and four build angles, zig-zag structures of four width reductions, and monolithic rectangular structures were manufactured using the EOS M290 powder bed fusion AM process. Mechanical and physical properties are determined through a multi-length scale approach. Variations in microstructure are characterized. Surface roughness is measured at "upskin" and "downskin" surfaces defined by build angles. Vickers hardness testing is coupled with tensile testing of selectively harvested mesoscale samples. The impact of build geometry and processing parameters is connected to the material response and mechanical properties.