The precise shape of a shift block support for the turbine blade of a hovercraft was additively manufactured using 17–4 precipitation-hardened stainless steel (STS 630) powder through laser powder bed fusion (LPBF). Subsequently, heat treatment under the H900 condition increased the yield strength and fracture strain of the shift block to 1313 MPa and 11.5%, respectively, and enhanced its corrosion resistance to seawater. This improvement in mechanical and physical properties is primarily because Cu precipitates were uniformly distributed at the interfacial boundaries along with the simultaneous suppression of the formation of Cr₂₃C₆ precipitates with weak corrosion resistance. Furthermore, this was attributed to the phase transformation from the as-built STS 630 comprising a mixture of austenite, ferrite, and martensite to a dual mixture of ferrite and martensite after the heat treatment. Thereafter, we topologically optimised the shift block and adopted a lattice structure to apply the design for additive manufacturing (DfAM).

Hexagonal boron nitride-reinforced Inconel 718 (h-BN/IN718) composites were fabricated using a laser powder bed fusion (LPBF) technique to treat a nanosheet-micropowder precursor mixture prepared in a mechanical blending process. Tailoring the BN in IN718 enhanced the thermal resistance of the composites, thereby dampening the sharpness of the melting temperature peak at 1364 °C. This is because the presence of the BN reinforcement, which has a low coefficient of thermal expansion (CTE), resulted in a heat-blocking effect within the matrix. Following this lead, we found that the BN (2.29 g/cm³) was uniformly distributed and strongly embedded in the IN718 (8.12 g/cm³), with the lowest alloy density value (7.03 g/cm³) being obtained after the addition of 12 vol% BN. Consequently, its specific hardness and compressive strength rose to 41.7 Hv_0.5·cm³/g and 92.4 MPa·cm³/g, respectively, compared to the unreinforced IN718 alloy with 38.7 Hv_0.5·cm³/g and 89.4 MPa·cm³/g, respectively. Most importantly, we discovered that the wear resistance of the composite improved compared to the unreinforced IN718, indicated by a decrease in the coefficient of friction (COF) from 0.43 to 0.31 at 2400 s. This is because the BN has an exfoliated surface and intrinsically high sliding and lubricating characteristics.

A hatching-distance-controlled lattice of 65.1Co28.2Cr5.3Mo is additively manufactured via laser powder bed fusion with a couple of periodic and aperiodic arrangements of nodes and struts. Thus, the proposed lattice has an amorphous-inspired structure in the short- and long-range orders. From the structural perspective, an artificial intelligence algorithm is used to effectively align lattices with various hatching distances. Then, the metastable lattice combination exhibits an unexpectedly high specific compression strength that is only slightly below that of a solid structure. From the microstructural perspective, the nodes in the newly designed lattice, where the thermal energy from laser irradiation is mainly concentrated, exhibit an equiaxial microstructure. By contrast, the struts exhibit a columnar microstructure, thereby allowing the thermal energy to pass through the narrow ligaments. The heterogeneous phase differences between the nodal and strut areas explain the strength-deteriorating mechanism, owing to the undesirable multi-phase development in the as-built state. However, solid-solution heat treatment to form a homogeneous phase bestows even higher specific compression strength. Furthermore, electrochemical leaching leads to the formation of nanovesicles on the surface of the microporous lattice system, thereby leading to a large surface area. A more advanced valve cage for use in a power plant is designed by using artificial intelligence both to (i) effectively preserve its mechanical stiffness and (ii) actively dissipate the generated stress through the large surface area provided by the nanovesicles.