【作者】 王秀英；

【导师】 王文魁； 刘日平； 孙力玲；

【作者基本信息】 燕山大学 ， 材料学， 2004， 博士

【摘要】 本文利用二次离子质谱、差示扫描量热分析、同步辐射 X-射线衍射等技术研究了多组元 Zr-基大块非晶合金在高压和质子辐照条件下的原子输运、结构弛豫和晶化动力学等问题。 高压原位同步辐射实验研究表明,Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀ 大块非晶合金在 0～32.8 GPa 的压力范围内的状态方程可表示为: 0. 012P2.49104 P29.5107P35.02108P4Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀ 大块非晶合金中含有一定量的自由体积,在压致结构弛豫的过程中,自由体积被压缩。压力较低时,体积变化率对压力变化比较敏感;压力较高时,体积变化率随压力的变化较小。利用添加原子 Mo 模拟了该大块非晶合金中 Nb 原子的自扩散过程。在 593～673 K 的温度范围内,Mo 原子在该大块非晶合金中的扩散系数随温度的升高而增大,其扩散激活能 Q 和前置系数 D₀的值分别为 1.95 eV 和 1.13×10^-5 m²s^-1。 研究了高压对 Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5大块非晶合金结构弛豫和晶化动力学的影响。研究发现,压力促进了该大块非晶合金的结构弛豫过程,随着压力的增大,自由体积减少,同时热焓降低。压力还促进了非晶合金的晶化过程,随着压力的升高,其晶化激活能降低。 研究了高压下 Co 在 Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5大块非晶合金中的扩散行为。603 K 时,Co 原子在该大块非晶合金中扩散系数随压力的增大而增大,计算得扩散激活体积ΔV *=-1.236Ω,为类间隙扩散机制。同时,该大块非晶合金的粘滞系数随压力的增大而减小,从 1 GPa 时的 1.79×10¹⁰ Pas 降到 4 GPa 时的 1.39×10⁷ Pas。 研究了质子辐照对 Zr_41.5Ti₁₅Cu_12.6Ni_10.5Be_20.4大块非晶合金结构弛豫和晶化动力学的影响。结果表明,质子辐照促进该大块非晶合金中原子的迁移能力,随着质子辐照剂量的增大,该大块非晶合金中的自由体积减少。经剂量为 1.1×10¹⁵和 6.5×10¹⁵ ions/cm₂ 的质子辐照后非晶合金的稳定性增加;而经剂量为 1.65×10¹⁶ ions/cm² 质子辐照后其晶化激活能和电阻率都有所降低,说明该大块非晶合金中的化学短程有序程度有所增加。更多还原

【Abstract】 amorphous alloys under high pressure and proton irradiation have been investigated by secondary ion mass spectroscopy, differential scanning calorimetry and synchrotron radiation x-ray diffraction. Effect of pressure on structural relaxation of Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀ bulk amorphous alloy has been studied by in situ high pressure technique. No phase transition was detected from ambient to 32.8 GPa. The equation of state for this alloy can been expressed by the equation as: There is an excess free volume in this bulk amorphous alloy which can be compressed during pressure-induced structure relaxation. It is clearl that compressible volume of the alloy is sensitive to pressure in a lower pressure range. But the compressible volume is smaller when pressure is increased. Self-diffusion of Nb in the bulk amorphous alloy is simulated by diffusion of Mo impurity atoms. The diffusion coefficients increased with temperature from 593 to 673 K, and the activation energy and pre-factor are of 1.95 eV and 1.13×10^-5 m²s^-1, respectively. Effect of pressure on structural relaxation and crystallization kinetics of Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5 bulk amorphous alloy has been studied. The results show that the free volume and enthalpy decrease with increasing pressure. Crystallization activation energy decreases with increasing pressure. Diffusion of Co in Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5 bulk amorphous alloy has been investigated under high pressure at 603 K. The results show that the diffusion coefficient of Co in the bulk amorphous alloy increases with increasing pressure. And the activation volume is obtained to be –1.236Ω which implies that diffusion of Co in this case is in an interstitial-like diffusion mechanism. Viscosity coefficient of the bulk amorphous alloy decreases from 1.79×10¹⁰ Pas at 1 GPa to 1.39×10⁷ Pas at 4 GPa at 603 K. Effect of proton irradiation on structural relaxation and crystallization kinetics of Zr_41.5Ti₁₅Cu_12.6Ni_10.5Be_20.4 bulk amorphous alloy has been investigated. Proton irradiation promotes the atomic movement in this bulk amorphous alloy. And the free volume of the alloy decreases with increasing the dose of the irradiation. The bulk amorphous alloy is more stable after proton irradiated with the dose of 1.1×10¹⁵ and 6.5×10¹⁵ ions/cm², respectively. Crystallization activation energy and electric resistance are decreased when irradiated with the dose of 1.65×10¹⁶ ions/cm², which implies that crystallization are promoted at a higher irradiation dose.更多还原