中子辐照对Pd_(80)Si_(20)与Pd_(77.5)Cu_6Si_(16.5)非晶态合金结构的影响

STRUCTURAL CHANGES IN AMORPHOUS Pd_(80)Si_(20) AND Pd_(77.5)Cu_6Si_(16.5) ALLOYS CAUSED BY NEUTRON IRRADIATION

本工作用X射线衍射技术示差扫描量热法(DSC)和内耗测量等手段研究金属-类金属非晶态合金Pd_(80)Si_(20)和Pd_(77.5)Cu_6Si_(16.5)中子辐照前后的微观结构变化。结果表明,辐照在两种样品的对关联函数g(r)以及径向分布函数RDF(r)上都引起明显的变化;辐照后样品的晶化温度和晶化热有所提高,结构变得更加无序,Pd_(80)Si_(20)非晶态合金的内耗在T<T_p的温度范围内增加。应用密度涨落型P缺陷和切变型τ缺陷的概念对其进行讨论。

The present work is to study effects of neutron irradiation on the structure of amorphous Pd80Si20 and Pd77.5Cu6Si16.5 alloys by using X-ray diffraction techniques, differential scanning calorimertry (DSC) and internal friction measurements. The irradiation appeared to produce obvious changes in the pair correlation function g(r) and radial distribution function RDF (r). The increases of crystallization temperature (Tx) and enthalpies of two specimens were found by DSC measurements after irradiation. The results of internal friction measurement show that the internal friction of the irradiated Pd80 Si20 alloy is higher than that of the unirradiated in the temperature range of T<Tp. The structure changes before and after neutron irradiation are discussed in terms of the concepts of density fluctuation defects (p) and shear stress fluctuation defects (τ).