Research On Welding Technology And Mechanism Of Metallic Glasses

Metallic glasses is a new kind of metal material with excellent comprehensive properties and has been used in many fields.The size of the metallic glasses is strictly limited by their amorphous forming ability.At the same time,it is necessary to overcome the problems of crystallization and brittleness to fabricate the metallic glasses with complex shape.These problems restrict the engineering applications of metallic glasses.Therefore,it is an inevitable trend of material development to explore new manufacturing technology of metallic glasses by optimizing welding process.Based on the metallic glasses ribbon La60Ni15Al25(hereinafter referred to as La-base)as the research object,the use of lowtemperature thermoplastic welding and pulse current spot-welding technology to explore the connection of La-base material behavior,and analysis of welding process parameters on the sample structure,the influence of the thermal physical and mechanics performance,so as to lay a foundation for the additive manufacturing of metallic glasses in the future,the main research contents and conclusions are as follows:(1)La-base ribbon was prepared by single-roll melt quenching process.X-ray diffraction(XRD),Differential Scanning Calorimetry(DSC)and room temperature uniaxial tensile method were used to analyze the amorphous structure,thermophysical properties and mechanical properties of La-base ribbon.(2)The low-temperature thermoplastic welding technology was used to investigate the welding properties and welding process of La-base ribbon.The activation energy of La-base ribbon was measured by isothermal DSC experiment and the soldering time window at each temperature was predicted.The welding performance and welding process of La-base ribbon was studied by testing the samples before and after welding.The mechanical properties of the welded samples are lower than that of the La-base ribbon.The"sandwich" structure is formed by the the La-base ribbon and the Zr-based ribbon with higher glass transition temperature and strength.The fracture strength of the obtained samples is increased by 19%,which is close to the strength of the La-base ribbon.The metallic glasses blocks with a diameter of 3mm were formed by using the optimized process parameters.(3)The pulsed current spot-welding technology was used to investigate the welding properties and welding process of La-base ribbon.Through a large number of experiments in the early stage to determine the experimental parameters,before and after the welding of the sample performance test to study the welding performance and welding process of La-base ribbon.Therefore,the forming size of the welding sample was increased by multi-layer welding to verify that the proposed method can effectively improve the forming size of the La-based metallic glasses.This technique is used to construct complex three-dimensional structures such as arch structures and tubes.