This paper demonstrates the successful printing of H13 tool steel by a selective laser melting (SLM) method at a scan laser speed of 200 mm/s for the best microstructure and mechanical behavior. Specifically, the nanoindentation strain-rate sensitivity values were 0.022, 0.019, 0.027, 0.028, and 0.035 for SLM H13 at laser scan speeds of 100, 200, 400, 800, and 1600 mm/s, respectively. This showed that the hardness increases as the strain rate increases and, practically, the hardness values of the SLM H13 at the 200 mm/s laser scan speed are the highest and least sensitive to the strain rate as compared to H13 samples at other scan speeds. The SLM processing of this material at 200 mm/s laser scan speed therefore shows the highest potential for advanced tool design. Residual stress is expected to affect the hardness and shall be investigated in future research.

Tungsten carbide (WC) in Ni-based powders is a promising candidate for laser-based additive manufacturing because WC is an extremely hard material, whereas Ni is tough and weldable. However, WC particles that are directly exposed to a laser beam can be degraded or disintegrated into tungsten and carbon as a result of excess energy. In contrast, particles in the melt pool are relatively stable. In this study, the direct energy deposition method was used with irregular and spherical WC particles in metal powder. Irregular WC particles were found to be more directly affected by laser irradiation. To explain the effects of WC particle shapes on direct laser damage, a finitepoint calculation was performed to estimate the sinking time in the melt pool. The rectangular shape particles a longer sinking time depending on the rotation angle, whereas the spherical particles sank uniformly based on the difference in the effective area of resistance.

This study investigates the challenges of additively manufactured interlocking structures, emphasizing joinability issues due to thermal deformation. These challenges become pronounced when fabricating high-density structures without fully interconnected layers, a trait common in soft magnetic materials. Here, a detailed analysis assessing deformation concerning pin thickness and build orientation in a representative interlocking model is performed. Utilizing stress and thermal simulations of the additive manufacturing process, it is shown that a compensated design considerably enhances the joinability of these structures. These findings offer valuable perspectives for advancing the design of additive manufacturing components, particularly in soft magnetic materials such as electric motor stators, which require both insulation and density.

In this study, we propose a cooling structure manufactured using a specialized three-dimensional (3D) printing design method. A cooling performance test system with complex geometry that used a thermoelectric module was manufactured using metal 3D printing. A test model was constructed by applying additive manufacturing simulation and computational fluid analysis techniques, and the correlation between each element and cooling efficiency was examined. In this study, the evaluation was conducted using a thermoelectric module base cooling efficiency measurement system. The contents were compared and analyzed by predicting the manufacturing possibility and cooling efficiency, through additive manufacturing simulation and computational fluid analysis techniques, respectively.

While crystal-inspired design has become a promising strategy for developing advanced mechanical metamaterials, the specific role of individual grain boundary interfaces on the macroscopic mechanical properties has remained unclear. This study aims to elucidate the importance of this interface by designing, fabricating, and testing bicrystal-inspired lattice structures. Using the Coincident Site Lattice (CSL) theory, we modeled various Σ5 tilt grain boundaries in a bicrystal configuration. These structures were fabricated from SUS316L powder using a powder bed fusion (PBF) additive manufacturing process. Compression tests revealed that the presence and type of the macroscopic “grain boundary” interface are critical determinants of the mechanical response, with symmetric bicrystal structures exhibiting a distinct two-stage collapse. More importantly, by engineering the fine structure of the interface itself, such as the density of connecting struts, the mechanical properties can be precisely tuned, achieving a systematic variation in yield strength from 9.1 MPa to 11.5 MPa. This work clarifies the crucial role of interfacial structure in crystal-inspired metamaterials and provides a clear design principle for creating lightweight, damage-tolerant structures with programmable mechanical responses.