Superplastic Bonding Of Zr-based Metallic Glasses In The Supercooled Liquid Regions

Metallic glasses (MGs) are potentially used in many fields due to their uniqueproperties, such as superior strength and hardness, excellent corrosion resistance andimproved wear resistance. In their supercooled liquid regions (SLR), MGs usuallyexhibit superplastic behavior which allows MGs to be shaped in the SLR.Furthermore,the superplastic forming is often combined with other processing techniques inmanufactures. For example, by combining superplastic forming (SPF) with diffusingboding (DB), a novel manufacturing technology(SPF/DB) can be developed, whichcan realize the diffusion bonding of MGs during forming.Zr-based bulk metallic glasses (BMGs), including Zr52.5Al10Cul5Nil0Be12.5,Zr55Cu30Ni5Al10, Zr46.5Ti8.5Cu7.5Ni10Be27.5(Vit4) and Zr41.2Ti13.8Cu12.5Ni10Be22.5(Vit1), were investigated for their high thermal stability and excellent mechanicalproperties. The effects of the thermal stability and structural relaxation of Zr-basedBMGs on the mechanical properties was studied by annealed in the supercooled liquidregion. The Zr-based BMGs were bonded to themselves and another Zr-based BMGin the supercooled liquid region, to find the right technology for bonding BMGs byanalyzing the interfacial structure, morphology and mechanical properties.A set of optimized superplastic bonding parameters was gotten by orthogonalexperiment of bonding Zr-based MGs. The structure and properties of the bondingsamples were characterized by X-ray diffraction (XRD), the nanoindentationtechnology, the differential thermal scanning analysis (DSC) and the scanningelectron microscopy (SEM). No crystallization was found from bonding sample byXRD, so it was still amorphous alloy, and thermal stability was reduced from DSCcurve as the same as the annealing results. The SEM and scratch graphic showedconnection interface was good, flat, which proved that mutual diffusion was generatedand good superplasticity bonding properties were realized. Nanoindentation and SEMsuggested that the performance of the interface were better than matrix and as-castBMGs, and no separation was occurred in BMGs bonding.