Research On Selective Laser Melting And Ultrasonic Additive Manufacturing Of Metallic Glass

Metallic glass is a kind of amorphous high-performance metallic material,which has the advantages of metal and glass.The strength of metallic glass material is 2-3 times higher than that of its corresponding crystalline metal material with the same composition,and it has superplastic deformation behavior in the over-cooled liquid region,which have broad application prospects in the fields of mechanical manufacturing,biomedicine,communications and electronics.However,subject to the critical size of forming,it is difficult to directly cast and produce large metallic glass,which limits it to become a new generation of structural materials.While maintaining the excellent physical and mechanical properties of metallic glass,and manufacturing bulk 3D parts by metallic glass powder or metallic glass thin strip additively is a hot topic in the field of metallic glass recently.In this paper,the main line of research is to process high-performance metallic glass parts with free-cracks,non-oxidation,and non-crystallization via the additive manufacturing.The selective laser melting additive manufacturing technology was employed to form bulk 3D parts by using metallic glass powder as the raw material.The formation mechanism of macro-micro cracks in the metallic glass during the laser additive manufacturing was studied,and the effects of the laser process parameters on the oxidation phenomenon in the processing was clarified.The bulk metallic glass parts and their crystalline metal composites were processed via the ultrasonic additive manufacturing with the metallic glass ribbons as raw materials.The influences of ultrasonic parameters on the phase composition,thermal stability,and mechanical properties of metallic glass were explored.The feasibility of low-temperature additive manufacturing with the metallic glass ribbons were clarified which has great significance for expanding the application field of metal materials.The main contents of this article are as follows:1.Investigated the feasibility of customized metallic glass powders for selective laser melting additive manufacturing.A digital microscope was used to characterize the two-dimensional and three-dimensional topography of single tracks.The influence of laser energy density on the forming mode of metallic glass and defects such as cracks and splashes in the single tracks were analyzed.The model based on the computational fluid dynamics and finite element coupling method was used to simulate and analyze the stress distribution of a non-uniform single track.The mechanism of crack formation in a single track was explored by combining experiments with simulations.2.The laser energy density for the processing of single layer was adjusted by changing the hatch distance.The mechanism of crack propagation under different laser energy densities was investigated,and the effects of repeated scanning and defocus scanning on suppressing crack propagation were explored.The ANSYS additive software was used to analyze the stress and deformation of the metallic glass parts to study the formation mechanism of macro-cracks in the selective laser melting.3.By using oxidation-resistant metallic glass powder as a raw material,the single track was processed on a 316 L stainless steel substrate via the selective laser melting.Digital microscope was used to characterize the morphology and color of the oxide on the surface of the formed sample and analyze the severity of the oxidation reaction during the processing.Flow 3D software was used to simulate the formation of the molten pool during the processing.A high-speed camera was used to record smoke plume images during the selected laser melting.The in-situ monitored plume information was combined with the oxidation phenomena and cross-section topography on the surface of the scanning tracks to explore the effect of laser energy density on the oxidation phenomenon and the formation of the molten pool during the selective laser melting.4.Metallic glass and its composite samples were processed via ultrasonic additive manufacturing by using metallic glass ribbons and Cu/Al crystalline metal ribbons as raw materials.Through the micro-characterization of the cross sections,the influence of ultrasonic process parameters on the internal joint quality of the formed sample was analyzed,and the feasibility of ultrasonic additive manufacturing of metallic glass and its crystalline metal composite was investigated.The XRD and DSC were used to analyze the effects of ultrasonic vibration on the phase composition and thermal stability of metallic glass samples.The effect of ultrasonic vibration on the mechanical properties of metallic glass and its composite samples was investigated via the nano-indentation.In this paper,the research on selective laser melting and ultrasonic additive manufacturing of metallic glass is conducted.The part with complex structure and no crack propagation was processed with metallic glass powder material.And the high-performance metallic glass parts was processed via the ultrasonic additive manufacturing with the metallic glass ribbons.The researching showed the huge application potential of additive manufacturing for metallic glass and its composites in the field of mechanical manufacturing,and laid the foundation for expanding the application of the additive manufacturing of metallic glass.