Tailoring Of Microstructure And Mechanical Properties Of Inconel 738 Alloy Based On The Hatching Distance

The effect of hatching distance (h) on the microstructure, dynamic recrystallization (DRX) behavior, texture evolution and mechanical properties of Inconel 738 alloy formed by selective laser melting (SLM) were systematically investigated by electron backscatter diffraction (EBSD) technique. The results show that the aspect ratio of the elongated columnar grains parallel to the build direction decreases and the morphology of grains changes from coarse elongated columnar grains to fine equiaxed grains with the increase of h, leading to orientation of the grains becomes more random. With the increase of h, the dynamic recrystallization volume fraction increases, and the dislocation density and strain in the recrystallized region are lower than those in the unrecrystallized region. With the increase of h, the type of casting texture changes, the texture mainly transforms from Rotated-Goss texture {110}<110> to Rotated-Goss texture {110}<110> + Cube texture {001}<100>, and the intensity of Cube texture gradually increases, while the intensity of the Rotated-Goss texture gradually weakens. Excellent room temperature mechanical properties (sigma(y)=933 MPa, sigma(uts)=1209 MPa, epsilon(4)=38%) of the as-deposited Inconel 738 alloy with appropriate hatching distance (h=70 mu m) can be obtained, thereby achieving good match of strength and ductility.