Research On Penetration Mechanism And Optimization Design Of Wf/Zr-based Bulk Metallic Glass Matrix Composite Rod

New type of piercing materials with stronger penetration performance are important development trend of kinetic energy projectile.As a new piercing materials,Wf/Zr-based bulk metallic glasses matrix composite has gathered some interest,because it exhibits better penetration performance than tungsten alloy but without radiological hazard like depleted uranium alloy.In this thesis,theoretical analysis,experimental study and finite element simulation are used to study the influence of deformation mode of Zr-based bulk metallic glasses matrix,tungsten fiber diameter and L/D of rod to the penetration mechanism of Wf/Zrbased bulk metallic glasses matrix composite rod.On this basis,the optimal design of Wf/Zrbased bulk metallic glasses matrix composite rod is studied.The penetration mechanism of the Wf/Zr-based bulk metallic glasses matrix composite rod,and high DOP and structure “selfsharpening” rods are obtained.The main contents could be summarized as follows:(1)Research on failure mode of Wf/Zr-based bulk metallic glassed matrix composite rod under the penetration environmentIn order to study the failure mode of Wf/Zr-based bulk metallic glassed matrix composite rod under the penetration environment,a model of strain rate and temperature rise of the rod are established based on Alekseevskii-Tate model of penetration,shock wave theory and equation of state of materials,and the penetration environment is calculated.According to the failure mode of tungsten fiber and Zr-based bulk metallic glass under the environment,the shear failure,plastic failure and the transition mode between the shear and plastic of Wf/Zr-based bulk metallic glassed matrix composite are revealed.A failure mode model of Wf/Zr-based bulk metallic glassed matrix composite rod under the penetration environment is established.(2)Effect of tungsten fiber diameter on the dynamic compression and penetration performance of Wf/Zr-based bulk metallic glassed matrix composite rodIn order to study the effect of tungsten diameter on the penetration performance of the Wf/Zr-based bulk metallic glassed matrix composite rod,the dynamic compression and penetration experiments are conducted.The experimental results show that the dynamic compressive strength and failure mode of the composite are not affected by tungsten fiber diameter.But the penetration performance is related to the tungsten fiber diameter,the smaller tungsten fiber diameter,the more stable penetration results.The shear penetration,“mushroom”penetration and the tungsten fiber bundles penetration of the composite rod are revealed,and a model of penetration mechanism of the composite rod is established.(3)Effect of L/D on penetration performance of Wf/Zr-based bulk metallic glass matrix composite rodTungsten fibre/Zr-based bulk metallic glass matrix composite is a potential penetrator material.In the present paper,the effect of L/D on the penetration performance of WF/Zr-MG rod is studied.Experiments and finite element method simulations of WF/Zr-MG and tungsten heavy alloy rods with L/D from 1.11 to 18.33 penetrating into armor steel targets are conducted.The experimental results show that penetration efficiency of WF/Zr-MG rods with large L/D are higher than that of WHA rods with the same L/D,because the penetration process is long enough to include a steady state penetration self-sharpening.The steady state penetration selfsharpening results in less kinetic energy consumed of rods during penetration.Longitudinal splitting occurs in WF/Zr-MG rods with L/D of 3.75 during the penetration process,which results in a much lower P/L than that of WHA rods with L/D of 3.75.A jacket structure could prevent the longitudinal splitting and increase P/L of WF/Zr-MG rods.P/L of jacketed WF/ZrMG rods with L/D of 1.11 is slightly lower than that of jacketed WHA rods with L/D of 1.11,because of its short penetration process without the steady state penetration self-sharpening.P/L curve fitted as a function of normalized impact velocity and L/D of the WF/Zr-MG rods into RHA shows the advantages of WF/Zr-MG rods over WHA rods increase with L/D.(4)Optimal design of Wf/Zr-based bulk metallic glasses matrix composite rodIn order to achieve better penetration performance of Wf/Zr-based bulk metallic glasses matrix composite rod,it is optimized based on the structures and materials,segmented and multicomponent structures are designed.The penetration experiments show that the segmented structures rods get penetration efficiency of 1.7 at less than 1900m/s,higher than the ultimate penetration efficiency calculated by fluid mechanics;and one multicomponent structure rods exhibit a structure “self-sharpening” feature,get excellent penetration performance.High penetration efficiency and structure “self-sharpening” rods are got by the optimal design,which provides more methods for the development of the Wf/Zr-based bulk metallic glasses matrix composite rod.