【作者】 王志华；

【导师】 陈光； 陈国良；

【作者基本信息】 南京理工大学 ， 材料科学与工程， 2006， 博士

【摘要】 本文以Zr_41.25Ti_13.75Cu_12.5Ni₁₀Be_22.5块体金属玻璃为基体，连续钨丝为增强相，系统研究了W_f／Zr基块体金属玻璃复合材料的制备、力学行为，特别是高速冲击行为，得到以下主要结果：针对现有W_f／Zr基块体金属玻璃复合材料制备方法存在的不足，发明了一种制备W_f／Zr基块体金属玻璃复合材料的新方法，成功制备出φ17×100mm的大尺寸无缺陷W_f／BMG复合材料试样。压缩实验表明：随着钨丝体积分数V_f的增加，W_f／Zr基块体金属玻璃复合材料压缩强度提高，V_f从0％增加到70％，强度从2000MPa增加到2560MPa，提高了24.5％，比文献报道的最大强度2250MPa提高13％；同时，塑性应变和断裂方式也随着V_f而变化：V_f＜50％，随着V_f的增加，剪切带和塑性应变量增加，试样断裂方式为剪切和劈裂；当V_f≥50％时，随着V_f的增加，剪切带和塑性应变量减少。当V_f为50％时，塑性最好，压缩应变值达22.5％，比文献报道的最大值18％提高25％。动态压缩实验表明，在应变率3000s^-1以下，W_f／Zr基块体金属玻璃复合材料的动态压缩强度随着应变率的增加而增加。与准静态压缩条件下的均匀脉络纹断口形貌不同，在高应变率下发生绝热剪切破坏，在含有部分脉络纹断口中，还出现了绝热引起的熔化区。采用弹性-理想塑性带应变失效的本构模型Plastic Kinematic模拟结果显示W_f／Zr基块体金属玻璃复合材料侵彻体在侵彻过程具有“自锐”现象，其动能降低比93W合金慢，表明W_f／Zr金属玻璃复合材料具有良好的应用前景。更多还原

【Abstract】 The fabracation, mechanical properties, especially high velocity impact behavior ofW_f/Zr based bulk metallic glass matrix composites were investigated whileZr_41.25Ti_13.75Cu_12.5Ni₁₀Be_22.5 acted as amorphous matrix and tungsten fiber reinforcement.The main results were followed:Step temperature-controlled and rapid quenching method was invented to prepareamorphous alloys and W_f/Zr based bulk metallic glass matrix composites to avoid theshortages of methods at present. Samples of W_f/Zr based bulk metal glass matrixcomposites without defect with the size ofφ17×100mm³ were successfully prepared withoptimized technical parameters.The compressive strength of W_f/Zr based bulk metallic glass matrix compositesincreases with the volume faction of tungsten fiber. The compressive strength increases24.5% from 2000MPa to 2560MPa when the volume faction of W_f increases from 0% to70%. The compressive strength increases 13% comparing with the reported maximumstrength of 2250MPa. At the same time, the strain and fracture mode of composites changewith the volume faction of tungsten fiber: when the volume faction is less than 50%, thestrain increases and fracture mode is shearing and splitting; when the volume faction ismore than 50%, the strain decreases. When the volume faction is 50%, plastic strainreaches maximum with the value of 22.5%, increased 25% comparing with the maximumstrain of 18% in literature.The dynamic compressive strength of composites increases with stress rate below3000s^-1. Being different from the unique vein pattern under quasistatic compress, adiabaticshear fracture occurs at high stress rate in dynamic compressive test. In addition to the veinpatterns in the fractural surface, some melting area is also observed.The simulation results with the constitutive model of elasticity-ideal plastic with straindisabled showed that W_f/Zr based metallic glass composites penetrators has the"self-sharpening" effect during the penetrating. The decrease of kinetic energy of W_f/Zrbased metallic glass composites is much slower than that of 93W penetrators.更多还原