Multi-material laser powder bed fusion additive manufacturing of architecturally designed dual-phase heterostructures using heterogeneous high-entropy alloys

Abstract

Since the concept of high-entropy alloys (HEAs) was introduced, the development of HEAs with synergistic strength and toughness has posed a significant challenge to researchers. Traditional approaches based on random biphasic solid-solution designs often suffer from high variability and poor controllability. In this study, a novel method for multi-material laser powder bed fusion (MM-LPBF) with staggered printing was developed. Using AlCuCoCrFeNi-HEA and MnCoCrFeNi-HEA powders as starting materials, three heterogeneous bi-metallic structures were fabricated. These include staggered multi-layer planar, staggered multi-layer rotating grating, and staggered multi-layer checkerboard structures. The printed bi-metallic structures exhibit a dual-phase heterogeneous composition, consisting of fine body-centered cubic (BCC) crystals and coarse columnar face-centered cubic (FCC) crystals. The interfaces between the dual phases are firmly bonded by transitional “dual-phase intercalation”. Experimental evaluations demonstrate that these structures possess enhanced interfacial strengthening and crack suppression, particularly the staggered multilayer checkerboard structure, which exhibits remarkable impact resistance and energy absorption across multiple reinforcement mechanisms. This study provides valuable insights for the field of metal-based multi-material additive manufacturing, offering new perspectives and potential applications for the future design and fabrication of diverse materials.