Crystallographic texture in an additively manufactured nickel -base superalloy

Laser-based directed energy deposition was used to additively manufacture a wall out of pre-alloyed powder of a nickel-base superalloy Inconel 625. The crystallographic texture of the wall has been characterized using neutron diffraction and electron backscatter diffraction. The measured pole figures show a strong Goss texture component ({011} < 100 >) plus a comparatively much weaker cube component ({001). < 100 >), both indicating that the < 100 >-direction of the majority of grains lies along the laser-scanning direction (or the length direction). The origin of the Goss texture is hypothesized to be a result of the preferential < 100 >-oriented dendrite solidification driven by the laser-induced heat flow, which is affected by the combined effect of laser power, absorption of powder, and laser scanning speed. The texture-induced mechanical softening is also presented. This study aids in understanding the processing-structure-property relationship in additive manufacturing.