Dual-scale Nb Composite Zr-based Amorphous Alloy Fabricated By Laser Additive

Amorphous alloys have many excellent properties due to their unique atomic arrangement and the advantages of both metal and glass.They have a wide range of applications in aerospace,biological medicine,electronic communication and other fields.However,due to the limitation of cooling rate,the traditional preparation method of amorphous alloy cannot prepare large size and complex shape amorphous alloy,which cannot meet the requirements of amorphous alloy in practical application.With the popularization of additive manufacturing technology,the design and manufacture of metal materials with complex geometry and large actual size can be realized,which provides a good opportunity for the preparation of amorphous alloys.However,the great residual stress and poor room temperature plasticity of the amorphous alloy in the process of additive manufacturing are easy to produce crack defects.Therefore,it is of great significance to suppress the crack in the fabrication of amorphous alloy by laser additive manufacturing.In this paper,Zr₅₀Ti₅Cu₂₇Ni₁₀Al₈ powder with good amorphous forming ability was selected as the raw material,and the amorphous alloy was prepared by coaxial powder feeding laser additive manufacturing technology.The crack defects were inhibited by preheating the substrate process to reduce the residual stress and adding ductile phase Nb to improve the plasticity of the amorphous alloy.The effects of XRD,SEM,TEM and room temperature compression test on the macroscopic morphology,microstructure and mechanical properties of Zr-based amorphous alloys were analyzed.Laser additive manufacturing technology is used to suppress the crack by changing the laser power,preheating the substrate and adding ductile phase.The results show that the preheating substrate can reduce the crack defects,but can not completely suppress the crack defects.The introduction of dual-scale ductile phase Nb successfully improves the plasticity of Zr₅₀Ti₅Cu₂₇Ni₁₀Al₈ amorphous alloy and inhibits the crack defects.By optimizing the process parameters,the yield strength and plastic deformation of Zr-based amorphous alloy fabricated by laser additive can reach 1.03GPa and 3%.The microstructures and interactions of two-scale Nb particles in Zr-based amorphous alloys were analyzed in detail.The multistage structure of dual-scale ductile phase composite amorphous alloy realized by laser additive manufacturing technology provides a new way to fabricate high-performance amorphous composite materials.