Crystallographic texture in an additively manufactured nickel-base superalloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2017-01, Vol.684 (C), p.47-53
• Main Authors: Ma, Dong, Stoica, Alexandru D., Wang, Zhuqing, Beese, Allison M.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Alloy powders; Alloying additive; Crystallography; Diffraction; Electron backscatter diffraction; Heat transmission; Inconel 625; Laser applications; Lasers; Neutron diffraction; Nickel alloys; Nickel base alloys; Pole figures; Scanning; Solidification; Superalloy; Superalloys; Texture
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2016.12.028

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} ) plus a comparatively much weaker cube component ({001} ), both indicating that the -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 -oriented dendritic 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.