Oxide dispersion strengthened(ODS) steels and W play an important role in plasma facing components(PFCs).However, complex multi-material structures in PFCs are manufactured by assembling discrete components using conventional techniques and subsequently fused together by a welding process, which creates weak interface zones with limited performance. In this study, a W/ODS-316L multi-material structures were integrally fabricated utilizing the laser powder bed fusion (LPBF) methodology. The study delves into the examination of interfacial diffusion characteristics, the underlying interfacial bonding mechanism, and the mechanical properties of the fabricated structures. The results showed that a good metallurgical bond in W/ODS-316L multi-material interfaces was attributed to Marangoni convection and the development of a keyhole during the forming process. These phenomena induced intensive elemental diffusion across the interface, resulting in a robust metallurgical bond. Furthermore, the presence of Y elements in the molten pool led to their attachment to the surface of un-melted W powder due to Marangoni convection. It caused abnormal diffusion of Y elements towards the pure W side of the interface. The Y element reduced the proportion of large-angle grain boundaries (LAGBs) of W close to the interface, from 36.44% to 18.90%, which further inhibited the initiation and extension of cracks. And the interfacial bonding strength reached 130.42 ± 3.27 MPa. Finally, the effect of W/steel composition gradient on the bonding phenomenon could provide a reference for the composition design and regulation of the bonding effect at multi-material interfaces. The utilization of LPBF technology for fabricating W/ODS-316L multi-material structures presents an alternative viable approach for PFC preparation.

Porous NiTi lattice structures are widely used in the manufacture of crucial components owing to their excellent shape memory effect, superelasticity, and high damping capacities. However, the specific strength and lightweight characteristics of porous NiTi lattice structures fabricated by conventional technologies are limited by unpredictability. In this work, three types of porous NiTi structures based on triply periodic minimal surface (TPMS) – Diamond, Gyroid, and Primitive – were designed and manufactured by the laser powder bed fusion (LPBF) additive manufacturing process. This work demonstrates LPBF is a feasible and efficient approach to fabricate highly accurate porous NiTi TPMS structures. Moreover, the influence of each of these structures on the mechanical and shape memory properties was investigated. Among the three structures, Gyroid had the smallest volume fraction deviation. Furthermore, the Diamond structure had the largest compressive modulus (782.82 MPa) and ultimate yield strength (163.14 MPa). The Gyroid and Primitive structures exhibit excellent elastic recovery deriving from high values of compressive modulus (662.44 MPa, and 703.29 MPa), and can maintain reliable structural robustness. The Primitive structure exhibited the lowest mechanical properties (37.80 MPa). During the cyclic compression test, Gyroid and Primitive show a smaller unrecovered strain than Diamond. Primitive shows the largest recovered strain during the heating process (6.98%). The higher mechanical flexibility of Primitive structure endows this structure with higher recovery ratio. During the direct compression test, the residual strain exhibits a positive correlation with the loading strain. All three structures exhibit good deformation recovery capability with a strain of 4%. At a strain of 12%, recovered strain during heating became the dominant factor in the recovery of the TPMS structure. Overall, porous NiTi TPMS structures are capable of reversible compressibility composed of rapid elastic recovery and controllable shape memory recovery. The unique performance of porous NiTi TPMS structure fabricated by LPBF renders it a highly efficiency energy-absorbing structure.