ZrNbCuNiAl块体非晶合金的晶化行为及性能研究

【作者】 李喜峰；

【导师】 杨元政；

【作者基本信息】 广东工业大学 ， 材料学， 2003， 硕士

【摘要】 本文采用铜模真空吸铸法制备Zr₅₇Nb_15-xCu_15.4Ni_12.6Al_x块体非晶合金，利用示差扫描热分析（DSC）、X射线衍射（XRD）和扫描电子显微镜（SEM）等现代检测手段分析样品的非晶形成能力与结构。利用多重扫描速率的非定温法（Kissinger法和Ozawa法）和定温法（Arrenius法）研究Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀块体非晶合金的晶化动力学，系统地研究了Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀块体非晶合金的晶化过程；同时也对其力学性能进行较深入的探讨。本文的研究结果表明： （1）Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀合金具有较强玻璃形成能力和较宽的过冷液相区，其T_g=697.5K，T_x=747.4K，过冷液相区ΔT=（T_x-T_g）约为50K。 （2）ZF₅₇Nb₅Cu_15.4Ni_12.6Al₁₀块体非晶合金的T_g、T_x、T_p1、T_p2等热力学性能均具有明显的动力学效应。 （3）各阶段晶化激活能分别采用Kissinger法和Ozawa法计算得出：其晶化第一阶段激活能分别为320.4kJ／mol和332.7kJ／mol；晶化第二阶段激活能分别为324.3kJ／mol和336.8kJ／mol；其晶化指数n约为1.60，说明晶化过程受扩散控制；Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀块体非晶合金的晶化过程基本以认为：非晶相→非晶相（α和β）→非晶相（α和β）+NiZr₂+未知相→非晶相（α和β）+NiZr₂+Zr₂Cu→NiZr₂+Zr₂Cu+未知相。 （4）Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀块体非晶合金断裂强度σ_bc高达1705Mpa，相对压缩率ε_c仅为0.104，其断裂形貌为脉状河流花纹，断裂强度随退火温度的升高而显著降低，并且断裂方式从韧性断裂转变为脆性断裂。 （5）Zr₅₇Nb₅Cu_15.4N5_12.6Al₁₀块体非晶合金显微硬度约为462H_v0.2，且其显微硬度随退火温度和保温时间的变化整体呈增加趋势，其后略有降低。 （6）在3％NaCl、10％HCl和10％NaOH水溶液介质中，Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀块体非晶合金在3％NaCl水溶液介质中具有较好的耐腐蚀性，而在10％NaOH水溶液介质中耐腐蚀性较差。更多还原

【Abstract】 In this paper, Zr57Nbi5_xCu15.4Nii2.6Alx bulk amorphous alloys were prepared by means of copper-mold vacuum suction casting and the glass forming ability(GFA) and structure were investigated by differential scanning calorimeter(DSC), X-ray diffraction(XRD), scanning electron microscope(SEM), etc. Differential scanning calorimeter was used to study crystallization kinetics of Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy by Kissinger and Ozawa equation under non-isothermal conditions and Johnson-Mehl-Avram model under isothermal conditions, respectively. The crystallization process of Zr57Nb5Cu15.4Ni12.6Al10bulk amorphous alloy has been also studied systematically. Moreover, mechanical properties of Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy have been discussed profoundly. The following results have been obtained:(1) Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy has larger glass forming ability(GFA) and a wider supercooled liquid region. The glass transition temperature(Tg), the onset crystallization temperature(Tx) and the supercooled liquid region defined by the difference between Tx and Tg are about 697.5K, 747.4K and 50K respectively.(2) Significant kinetic effect has been found in the glass transition temperature, the onset crystallization temperature and the crystallization peak temperature.(3) Apparent activation energy of crystallization of Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy has been obtained with Kissinger and Ozawa equation, the apparent activation of crystallization of the first stage is 320.4kJ/mol and 332.7kJ/mol and that of crystallization of the second stage is 324.3 kJ/mol and 336.8 kJ/mol respectively. The avrami exponential of crystallization, n, is about 1.60, which implies the process of crystallization is under control of diffusion process. The whole process of crystallization for Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy may be considered as: amorphous - amorphous( a and 3 ) - amorphous( a and P )+NiZr2+unknown-n-phases-amorphous(a and 3 )+NiZr2+ Zr2Cu-NiZr2+Zr2Cu+unknown phases(4) The compressive fracture strength of Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy reaches 1705MPa, Compression ratio is only 0.104, fracture surface morphology takes on uniformly distributed veinal pattern. Fracture strength decreases obviously with the increase of annealing temperature and the mechanism of fracture changes form ductile fracture to brittle fracture.(5) Microhardness of Zr57Nb5Cu15.4Ni12.6Al10 bulk amorphous alloy is about 462Hvo.2, which depends on the annealing temperature and holding time. The microhardness shows a tendedcy to increase evidently, then falls slightly with the two annealing parameters.(6) In 3%NaCl, 10%HC1 and 10%NaOH water solution, the corrosion resistance of Zr57Nb5Cu15.4Ni]2.6Al]o bulk amorphous alloy is best in 3%NaCl solution and rather bad in 10%NaOH solution.更多还原