Laser 3D Printing Of Zr-based Bulk Metallic Glass Composites

Bulk metallic glasses(BMGs)have a series of excellent mechanical properties such as high strength,high hardness,high fracture toughness and high elastic limit,however it is only widely used in the field of soft magnetic properties.As a kind of structural material,bulk metallic glasses(BMGs)have not been widely applied,and the main reason for that did not obtain the widespread application is owing to the two bottleneck about the brittle and critical size.And the emergence of laser 3D printing technology provides an opportunity to solve the above problems.In this paper,we selected Zr39.6Ti33.9Nb7.6Cu6.4Be12.5 bulk metallic glass composites as the research object of this paper,and continue to prepare Zr-based bulk metallic glass composites without crack defects.The morphology,microstructure and mechanical properties of samples were analyzed by means of XRD,DSC,SEM and room temperature tensile test.Single channel,multi-channel and multi-layer experiments have been used to analyze the single factor of laser parameters.The basic technological parameters such as laser spot diameter,powder delivery,air delivery,lap rate,printing path and Z shaft lifting amount are determined.The P=1400W,v=600mm/min and P=1000W,v=600mm/min are determined as the parameter for the first layer experiment and the double layer experiment.And the influence of laser power and scanning rate was studied.The laser power increases,the larger the dendrite phase is,the greater the crystallization degree is,the smaller the amorphous content is,the better the forming quality and the printing effect are;And the scanning rate increases,the smaller the crystal size is,the smaller the crystallization degree is.the larger the amorphous content is,the less the forming quality and printing effect are.Large size block were prepared with the best laser process parameters.With the increase of the number of printing layers,the crystal shape changed from the narrow and short to cluster and shape,grain size increases,the degree of crystallization is more serious,and the content of amorphous alloy decreases.From the bottom to the top in the same printing layer,the grain size increases,the degree of crystallization is more serious,and the amorphous content decreases.From the tensile test at room temperature,the yield strength ?s of the specimen prepared by laser 3D printing technology is 835MPa,and the fracture strength ?f is 880MPa,which is brittle fracture.The plastic strain of the samples prepared by arc melting technology can reach 7.98%,the yielding strength as is 925 MPa and the fracture strength ?f is 950MPa.