Preparation, Structure And Mechanical Properties Of TiZr-based Amorphous Alloy Composite

In this paper, with changing Ti32.8Zr30.2Ni5.3Cu9Be22.7 amorphous alloy as the matrix, three kinds of TiZr-based amorphous alloy composite materials were designed by combining with the pseudo ternary phase diagram. The Ti/Zr elements content in the alloy matrix was optimized and different contents of Nb were adding to the alloy matrix. Ti32.8Zr34.8Cu6.2Be16.2Nb10, Ti45Zr22.6Cu6.2Be16.2Nb10 and Ti50Zr22.6Cu6.2Be16.2Nb5(TZ1、TZ2、TZ3 are the abbreviation of the three components, respectivly).Three amorphous composite materials are prepared by non consumable vacuum arc furnace. The phase composition and thermal properties of the composite are analyzed and characterized by XRD diffraction and Differential Scanning Calorimetry(DSC), respectively.The morphology and element distribution law of the composite materials are analyzed by Scanning Electron Microscope(SEM) and Energy Dispersive Spectrometer(EDS). The plastic deformation mechanism of the composite is analyzed by Transmission Electron Microscopy(TEM). The mechanical properties of three kinds of composite materials are tested by Instron universal testing machine.The experimental results show that the composite which is composed by β-(Ti,Zr,Nb) phase dendrites and amorphous matrix can be obtained by replacing element Nb with element Ni of the amorphous alloy and adjusting the titanium/zirconium ratio of the matrix alloy of the Ti32.8Zr30.2Ni5.3Cu9Be22.7 amorphous alloy. Because of the addition of beta phase stable element Nb, alloy melt induces the nucleation and growth of the β phase during solidification process, thus the dendrites are formed in the amorphous matrix. With the change of the Ti/Zr ratio of matrix alloy and the element content of niobium, the branch crystal morphology and size of the β-(Ti,Zr,Nb) phase change,and when the atomic percentage of niobium is 5, The size of branch crystal is relatively small and the branch crystal is in a state of isometric crystal.The mechanical test results show that the stress-strain curves of the three kinds of composites show plastic deformation capacity with different degree, especially the plastic strain of TZ1 composites reaches 23.3%, but the strength is still maintained at 2543 MPa. It is considered that the plastic of the amorphous composite is caused by the deformation of the dendrites, hiding the extension of the shear band and inducing the synergistic effect of the multiple shear bands.