The Research On Preparation And Superplastic Deformation Of TiZr-Based Metallic Glass Composites

TiZr-based metallic glass composites overcome the brittleness of amorphous alloy at room temperature and retain the high strength advantage of amorphous alloy,so it is a kind of structural material which has excellent mechanical properties.The study of superplastic deformation behavior can guide the establishment,development and improvement of the theoretical model in the supercooled liquid phase zone,and will accelerate the practical application of materials.In this paper,the microstructure and mechanical property of TiZr-based metallic glass composites which have 10%～50%crystallization fraction are investigated at room temperature.Meanwhile,the optimum superplastic deformation window of the corresponding specimens is obtained by using the compression experiment in high temperature.Finally,according to the optimal superplastic deformation window,the effect which the dendritic phase contents on the microstructure and mechanical properties of high temperature compression is studied.Conclusions as follows:（1）By changing the Ti-Zr-Cu-Co-Be content of the alloying elements obtain bornβ-Ti crystalline phase content reach 8%,38.2%and 55.6%of metallic glass composites.As the primaryβ-Ti content increase,crystal phase will by granular to fine dendrite crystal phase and the coarse dendrite,and room temperature plasticity increases,the true strain up to 0.088.In addition,large compression deformation can lead to martensitic transformation of crystal phase.（2）In the supercooled liquid region,a sample which primaryβ-Ti crystal phase content reach 8%are investigated in high temperature compression,study found that the deformation temperature around 630 K,the initial strain rate is lower than 1×10^-3s^-1,the strain rate sensitivity index m between 0.8～0.9 and true strain still reaches 0.7,indicating the sample have the capability of superplastic deformation.（3）When the sample is compressed at high temperature in the supercooled liquid phase,the plasticity decreases with the increase of the crystal phase content.During the process of hot compression,the crystal phase deforms obviously and martensitic transformation occurs.In the process of high temperature compression,new nanocrystalline phases are formed in the amorphous matrix.（4）After hot compression,selecting the 623 K samples research mechanical property in the room temperature,study found that the samples show a brittle fracture trend under room temperature compression,almost no plasticity at room temperature,and with the content which primaryβ-Ti crystal phase increase,the fracture strength decrease.