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Herein, laser powder bed fusion (LPBF) and casting Inconel 713 are used as the experimental materials for comparing the microstructure, mechanical properties, and fatigue characteristics. According to the results, the LPBF specimen has a columnar grain morphology that completely differs from the dendritic structure in the casting specimen, little difference in the hardness of the two specimens. In terms of mechanical properties, the LPBF specimen shows higher strength than the casting specimen but slightly lower ductility. In terms of fatigue characteristics, the LPBF specimen is better than the casting specimen under all loadings. For the LPBF specimen, solution heat treatment is used, which can cause the γ' phase to precipitate on the grain boundary and result in a texture effect. This promotes fracture during tensile and considerably reduces ductility. Nevertheless, the unheated LPBF Inconel 713 exhibits better strength and fatigue properties than casting specimens and can, thus, replace the traditional casting materials in the aerospace industry.

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In this study, an Al-Mg-Sc-Zr alloy fabricated through selective laser melting (SLM) was subjected to a single-stage heat-treatment process and a two-stage heat-treatment process to determine the effect of heat treatment on the tensile properties and fatigue properties of the alloy at room temperature and high temperatures. The results indicated that heat treatment caused the precipitation of Al3(Sc, Zr), thus increasing the tensile strength. The dynamic strain aging of the SLM Al-Mg-Sc-Zr alloy disappeared as the tensile temperature increased. The alloy exhibited the highest tensile strength after it was subjected to the single-stage heat treatment at both room temperature and high temperatures owing to the precipitated phase distribution at the melting pool boundaries. However, fatigue resistance and high-temperature necking of the as-printed SLM Al-Mg-Sc-Zr alloy were problems that could not be resolved with the single-stage heat treatment. In the two-stage heat treatment, the precipitated phases exhibited a uniform distribution in the matrix, thereby reducing the high-temperature necking phenomenon. The two-stage heat treatment helped reduce the melting pool interface effect and strengthen the matrix, restricting the propagation of fatigue cracks and increasing the fatigue life of materials.