Grain Morphology and Mechanical Properties Tailoring of Inconel 625 Alloy Fabricated by Laser Powder Bed Fusion

Abstract

The controlling strategies of grain morphology and mechanical properties of Inconel 625 alloy by laser powder bed fusion are investigated, and beyond that, the effects of phase composition, grain morphology, and crystallographic texture on mechanical properties are also studied. The phase evolution is insensitive to the scanning strategies, and all of the samples are composed of γ‐Ni phase. The (001) texture orientation tends to increase with the scanning rotation angle, and the sample IV fabricated by scanning strategies of 90° shows the highest (001) texture. Different grain morphologies can be tailored by controlling the direction of heat flow between continuous layers via changing scanning strategies. The proportion of large elongated columnar crystals gradually decreases, while the proportion of the equiaxed grains gradually increases as the scanning strategies change from 0°→90→67°→45°. The rotation angle increases from 0° to 45°, and the ultimate tensile strength and yield strength increase from 1267 ± 12 to 1304 ± 5 MPa and 760 ± 10 to 801 ± 5 MPa, respectively, which is attributed to the different stress states presented in the columnar crystals and the equiaxed crystals.