The Investigation Of Ag's Addition Effects On Zr₅₇Al₁₅Co₂₈ Metallic Glass

In this thesis, Zr₅7Al₁5Co₂0Ag₈ and Zr57Al15Co28 metallic glasses were selected, the structures of both alloys were detected and compared by the XRD and the DSC measurements. The addition of the Ag has large impact on the structure and the performance parameters of the Zr57Al15Co28. The results show that the first crystallization temperature of Zr₅7Al₁5Co₂0Ag₈ is about 787.5 K which is ahead of 806.4 K of the Zr57Al15Co28. We investigated the crystallization kinetics of both metallic glasses through Kissinger equation, which show that the crystallization activation energy of the Zr₅7Al₁5Co₂0Ag₈ and the Zr57Al15Co28 is about 521.5 KJ/mol, 375.9 KJ/mol respectively.Instrumented Nano-indentation experiments that were conducted to compare the elastic properities of both metallic glasses and to analyse the effect of loading rate on elastic modulus and hardness. The results show that the gradient of the loading and unloading curve of Zr57Al15Co28 under 5000μN is steeper than Zr57Al15Co20Ag8, which is a distinct symbol that the elastic properity of Zr57Al15Co28 is superior than Zr57Al15Co20Ag8. The addition of Ag give rise to the enhancement of plastic deformation and the weakness of elastic properity of Zr₅7Al₁5Co₂0Ag₈ metallic glass.Utilizing the high pressure synchronization radiation technique to study the compressibility of the Zr₅7Al₁5Co₂0Ag₈ and the Zr57Al15Co28, we gained the equation of the state accurately as follows: -ΔV₀ / V₀ =-0.06959+0.00971P-1.16447×10_-4P₂+4.70907×10_-6P₃ -ΔV₀ / V₀ =-0.10844+0.02143P-6.90900×10_-4P₂+8.02256×10_-6P₃The corresponding B (elastic modulus) of Zr₅7Al₁5Co₂0Ag₈ and the Zr57Al15Co28 are 102.98 GPa and 46.66 GPa respectively.High pressure experiments were performed for Zr₅7Al₁5Co₂0Ag₈ alloys by the cubic anvil high pressure apparatus under 300℃to investigate the influence of pressure on crystallization and phase transformation course of Zr₅7Al₁5Co₂0Ag₈ metallic glass; The Ozawa curve is fitted linearly to investigate the annealing effect under high pressure on kinetics behavior of the Zr₅7Al₁5Co₂0Ag₈ metallic glass. The final data indicate that the crystallization activation energy have great relation with high pressure; The average hardness and elastic modulus is developing towards the higher values while the hardness values are more dispersive than elastic modulus values.