Microstructure, cracking behavior and mechanical properties of Rene 104 superalloy fabricated by selective laser melting

Selective laser melting (SLM) is a progressive forming technique for manufacturing complicated components, whereas the microcracks emerge in the preparation process of powder metallurgy (PM) nickel-based superalloy samples undesirably. In this study, Rene 104 PM nickel-based superalloy samples were prepared by SLM, and the microstructure, cracking behavior and mechanical properties of the as-printed samples were systematically investigated. The results demonstrate that the microstructure of the SLMed Rene 104 alloy is composed of sub-micron cellular structures on the XY plane, and columnar grains paralleled to building direction on the XZ plane, which is corresponding to the intense < 001 > fiber texture. Both the solidification cracking and liquation cracking propagate along the high angle grain boundaries (HAGBs) in the SLMed Rene 104 samples, among which thermal stress and low melting point gamma-gamma' eutectics have significant effected on cracking behavior. Additionally, the tensile performance of as-fabricated Rene 104 samples is obviously anisotropic, which is ascribed to the directional growth of columnar grains with < 001 > fiber texture and the microcracks are perpendicular to the tensile test direction. This research provides the relationship among the microstructure, microcracks and mechanical properties for the Rene 104 PM nickel-based superalloy fabricated by SLM and exhibits the potential to fabricate similar alloys without cracks. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Selective laser melting (SLM) was used to prepare Rene 104 PM nickel-based superalloy samples, which exhibited unique microstructure and cracking behavior, resulting in significant anisotropy in tensile performance.