Effect Of Ag Substitution On Glass Form Ability And Mechanical Properties Of ZrCuAlNiTi Bulk Amorphous

Due to its unique long-range unordered short-range order structure and high strength,high hardness,corrosion resistance and other excellent properties excellent,amorphous alloys have broad application potential.However,the scope of applications is limited due to amorphous glass form ability and poor plastic properties.Studies have shown that amorphous alloys are very sensitive to elemental changes and compositional changes.Therefore,element substitution and addition are important means to increase the amorphous formation ability to study the plastic deformation mechanism.In this paper,on the basis of Zr₅₆Cu₂₄Al₉Ni₇Ti₄ amorphous alloy,replacing the Ti element or Ni element,prepare 8 kinds of amorphous alloys with different diameters.They were Zr₅₆Cu₂₄Al₉Ni₇Ti_4-xAg_x?x=0,1,2,3,4?and Zr₅₆Cu₂₄Al₉Ni_7-x-x Ti₄Ag_x?x=0,1,3,5,7?,respectively.The amorphous alloy structure was characterized by X-ray diffraction?XRD?and transmission electron microscopy?TEM?.The thermal properties of the amorphous alloy were analyzed by differential scanning calorimetry?DSC?.Mechanical properties and fracture characteristics of the material were analyzed by compression experiments and scanning?SEM?.Through XRD,TEM experimental results,we can know that the substitution of Ag element makes the critical dimension of both amorphous alloy systems increase.The critical size of the initial amorphous alloy Zr₅₆Cu₂₄Al₉Ni₇Ti₄ is 3mm<Zc<5mm,and there are five kinds of amorphous alloy components after Ag element replacement.Including Zr₅₆Cu₂₄Al₉Ni₇Ti₂Ag₂,Zr₅₆Cu₂₄Al₉Ni₇Ti₁Ag₃,Zr₅₆Cu₂₄Al₉Ni₆Ti₄Ag₃,Zr₅₆Cu₂₄Al₉Ni₄Ti₄Ag₃,Zr₅₆Cu₂₄Al₉Ni₂Ti₄Ag₅ can be stably cast into 6mm amorphous rods.The thermal properties of the amorphous alloy system were characterized by DSC experiments.The analysis of the results shows that with the increase of Ag element,the supercooled liquid region of Zr₅₆Cu₂₄Al₉Ni₇Ti_4-xAg_x?x=0,1,2,3,4?amorphous alloy increases to 103K,and the thermal stability increases.However,the width of the supercooled liquid region of the amorphous alloy Zr₅₆Cu₂₄Al₉Ni_7-xTi₄Ag_x?x=0,1,3,5,7?decreased to 45K.The mechanical properties of the material were analyzed by means of experimental tests such as Vickers hardness and compression tests at room temperature.With the increase of Ag content,the Vickers hardness of Zr₅₆Cu₂₄Al₉Ni₇Ti_4-xAg_x?x=0,1,2,3,4?system increases,while that of Zr₅₆Cu₂₄Al₉Ni_7-xTi₄Ag_x?x=0,1,3,5,7?system.Hardness decreases.The compression plasticity increases first and then decreases with the increase of the amount of Ag.The increase in compression plasticity is dependent on the increase in free volume,which allows the shear band to propagate and induce multiple shear bands to increase the amorphous alloy plasticity.By scanning the compression side surface and the fracture of the specimen,it can be seen that when the specimen is compressed,the shear fracture of the specimen is less than45°.There are two fracture modes in the fracture:shear fracture and fracture fracture.There is a ridge pattern on the surface of the shear fracture,and the more dense the grain,the stronger the amorphous plasticity.The surface of the broken fracture surface is similar to that of the mountain and gully,which indicates that the normal stress and the shear stress are affected during compression.