The Study Of Preparation,crystallization Behavior And Properties Of Zr-based Amorphous Alloy With High Zr Content

Zr-based glass alloys with high Zr content exhibit excellent thermal stability,high hardness,low elastic modulus and high elasticity.As structural materials of nuclear plants,Zr atom is one of the crucial elements due to its low neutron-capture cross-section.Therefore,the Zr-based bulk metallic glasses exhibit a great potential in engineering applications.However,the macroscopic brittleness of glass alloys during compression or stretching at room temperature and the low glass formation ability of high Zr glass alloys limit their applications for engineering materials.Therefore,improving the glass formation ability and plasticity of high Zr content glass alloys is the research direction of Zr-based glass alloys.In the present work,ternary Zr-Al-Ni amorphous alloy with simple composition is primary components of Zr-based glass alloy.The Cu and Ag elements substitute for Ni element in Zr-Al-Ni glass alloy,and design Zr-rich exceed 70 at.%Zr-based glass alloys.Zr-based glass ribbons,glass rods and glassy composite materials were prepared by the melting spun technique,copper module injection casting thermal treatment,respectively.Moreover,Zr-based alloys have been systematically investigated glass formation ability,thermal stability,crystallization kinetics and mechanical properties.The experimental results are summarized as follows:1.Ternary Zr_70-74Al_7-7.5Ni_19-22.5 glass ribbons with Zr content over 70 at.%were prepared.The effect of Zr content on the thermal stability and mechanical properties were investigated.The results show that the glassy phase atomic configuration changed with the increasing of Zr content,resulting in the change of the initial precipitated phase from IQ phase to[β-Zr+ω-Zr]phase.The annealing-induced[G+IQ]and[G+β-Zr+ω-Zr]phase of high Zr alloy ribbons retain good bending plasticity and show the 560-524 value of Vickers hardness.2.The effects of Cu addition on the glass formation ability and mechanical properties of Zr_70-76Al_7-7.5Ni_15-20Cu_2-2.5 glass ribbon were systematically investigated.The addition of Cu element can improve the glass formation ability of Zr-based glass alloys.The bulk metallic glasses（BMG）with high strength and strain of 11.3%were prepared.The large strain is due to the existence of free volume in the glass alloys.Annealed induced nanocrystalline precipitation with[G+IQ]and[G+β-Zr+ω-Zr]in bulk metallic glasses composites can increase the strength and maintain a large strain of 1.3-3.9%of Zr-based BMG.3.The structure,thermal stability and mechanical properties of quaternary Zr_70-76Al_7-7.5Ni_15-20Ag_2-2.5 glass ribbon and bulk metallic glasses were investigated.The bulk amorphous and amorphous composites with high strength and large plasticity were prepared.Minor addition of Ag can improve the amorphous forming ability and the plasticity of annealed-induced[G+IQ]structure of Zr-based glass alloy.The reason is the Ni-Ag atomic pair with positive heat of mixing configurations which hinders the crystallization of the alloy.4.The structure,thermal stability,mechanical properties and deformation microstructure of new quinary Zr-rich Zr_70-76Al_7-7.5Ni_13-15Cu₂Ag_2-5 alloys have been investigated.The Zr_70-72Al_7-7.5Ni₁₅Cu_2-2.5Ag_4-5 bulk metallic glasses and Zr₇₄Al₇Ni_14.15Cu₂Ag_2.5 alloy with[G+β-Zr+trigonalω-Zr+hexagonalω-Zr]structure showing high strength and large plasticity were prepared.The plastic deformation for the occurs via the primary deformation ofβ-Zr phase as well as the deformation-inducedβ-Zr→ω-Zr displacive type transformation.