Highlights: The printability, microstructural characteristics, phase transformation behaviors, and mechanical properties of LPBF-fabricated NiTi alloys are reviewed. Several common structures for LPBF-fabricated NiTi alloys are considered and their various fields of application are illustrated. The technical challenges, limitations, and development tendencies of LPBF-fabricated NiTi alloys are put forward.

Continuous industrialization and other human activities have led to severe water quality deterioration by harmful pollutants. Achieving robust and high-throughput water purification is challenging due to the coupling between mechanical strength, mass transportation and catalytic efficiency. Here, a structure-function integrated system is developed by Douglas fir wood-inspired metamaterial catalysts featuring overlapping microlattices with bimodal pores to decouple the mechanical, transport and catalytic performances. The metamaterial catalyst is prepared by metal 3D printing (316 L stainless steel, mainly Fe) and electrochemically decorated with Co to further boost catalytic functionality. Combining the flexibility of 3D printing and theoretical simulation, the metamaterial catalyst demonstrates a wide range of mechanical-transport-catalysis capabilities while a 70% overlap rate has 3X more strength and surface area per unit volume, and 4X normalized reaction kinetics than those of traditional microlattices. This work demonstrates the rational and harmonious integration of structural and functional design in robust and high throughput water purification, and can inspire the development of various flow catalysts, flow batteries, and functional 3D-printed materials.

Selective laser melting (SLM) offers great possibilities to fabricate metal tools with a complex geometry, but there are limitations regarding some materials. This work focuses on the fabrication of AISI 420 stainless steel using SLM for the application of plastic injection mold. The melt characteristic of the powders was firstly concluded, and then the microstructure, phase composition, and hardness were characterized using scanning electron microscopy, X-ray diffraction, and Rockwell hardness test, respectively. The results showed that cellular microstructure was observed along the direction of the maximum heat flow. The proportion of the phases varies with the change of SLM processing parameters, which directly affects on the hardness of the parts. The relative density over 99% was obtained and the highest hardness presents 50.7 HRC, which meets the requirement of plastic injection molding application.