通过球磨混粉的方式在316L不锈钢3D打印专用粉体表面引入纳米V8C7颗粒,利用选区激光熔化(SLM)技术制备了V8C7/316L复合材料试样及点阵结构件。在优化的SLM工艺参数下获得的复合材料实体件的致密度高达99.4%;在激光熔化-凝固过程中,V8C7通过分解-析出机制生成的VCx增强相成为纳米级形核质点,其在细化奥氏体相晶粒的同时沿奥氏体晶界分布,可以阻止奥氏体晶粒在快速凝固过程中的长大;纳米尺度的VCx增强相及超细的近等轴晶金属基体均有助于大幅提升增材制造V8C7/316L结构的比强度。

Herein, V₈C₇ nanoparticles were mixed with 316L stainless steel powder via ball-milling for selective laser melting (SLM)-assisted three-dimensional (3D) printing. Then, a lattice structural V₈C₇/316L composite was printed via SLM. Using optimized SLM process parameters, the density of composite solid parts as high as 99.4% was achieved. In addition, during the laser melting-solidification process, VC_x reinforcements were generated via the decomposition-precipitation mechanism of V₈C₇ as the nanoscale nucleation sites. Consequently, the dispersed VC_x nanoparticles were preferentially distributed along the austenite grain boundaries, thereby further inhibiting the grain-coarsening of austenite during rapid solidification. The nano-VC_x reinforcements and the ultrafine metal-matrix grains that were nearly equiaxed, contributed to a significant increase in the specific strength of V₈C₇/316L lattice structures.