Tensile behavior of large size Zr-based bulk metallic glass composites prepared by selective laser melting

A Zr55Cu30Al10Ni5 (Zr55) bulk metallic glass composite (BMGC) with a size of 37 x 37 x 10 mm3 was fabricated by using selective laser melting (SLM) additive manufacturing technology with argon gas atomized (GAed) powder. The microstructure and tensile deformation behavior of SLMed Zr55 BMGCs are investigated. The microstructure evolution perpendicular to the laser scan direction exhibits a periodic microstructure with three different zones (amorphous, nanocrystal + amorphous and dendritic eutectic + nanocrystal zones). The stepwise tensile fracture behavior, mixing ductility with a sharp stress drop after the failure of amorphous layers is shown for the Zr55 BMGC. The nanocrystal + amorphous crystalline zone has a lower hardness and elastic modulus than the amorphous zone via the nanoindentation test, therefore, the stress drops obviously when the hard amorphous layers fail and then stress recovery follows as the soft crystalline layers pick up the load, resulting in a final failure strain of 9%. The results further verified the feasibility of SLM technology for the development of high-performance BMGCs for industrial applications.