Document Type

Article

Publication Date

11-15-2019

Abstract

The tension-tension fatigue behavior of heat treated selective laser melted (SLM) nickel alloy 718 (IN718) tensile specimens was tested and compared to as-built specimens. In addition to the industry standard IN718 heat treatment, a modified heat treatment was developed and tested in order to mitigate the anisotropic mechanical properties inherent to SLM materials. Electron backscatter diffraction verified that the modified heat treatment significantly affected the microstructure in all build planes. Three different print orientations were studied to determine their effect on the fatigue behavior. Both heat treatments improved the fatigue life of the specimens, although neither surpassed the fatigue life of wrought specimens. The modified heat treatment reduced the effect of the print orientation on the fatigue life. Surface roughness estimates made by laser scanning microscopy revealed a threshold between roughness controlled fatigue life behavior and print orientation fatigue life dependence. Fracture surface analysis indicated that the print orientation was the greatest factor that influences crack initiation and propagation.

Comments

Publisher version at ScienceDirect: https://doi.org/10.1016/j.matdes.2019.108095

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. CC BY 4.0 https://creativecommons.org/licenses/by/4.0

Sabelkin, V. P., et al. (2019). Mitigation of anisotropic fatigue in nickel alloy 718 manufactured via selective laser melting. Materials and Design, 182, 108095. https://doi.org//10.1016/j.matdes.2019.108095

DOI

10.1016/j.matdes.2019.108095

Source Publication

Materials and Design

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