金属玻璃形成液体的热力学特性  

Thermodynamic characteristics of metallic glass-forming liquids

作　　者：夏明许[1] 孟庆格[1] 张曙光[1] 马朝利[2] 李建国[1] 

机构地区：[1]上海交通大学材料科学与工程学院,上海200030 [2]北京航空航天大学材料科学与工程学院,北京100083

出　　处：《物理学报》2006年第12期6543-6549,共7页Acta Physica Sinica

基　　金：国家杰出青年科学基金(批准号:50125101)资助的课题.~~

摘　　要：通过分析规则熔体的热力学模型,计算了典型金属玻璃的熔体混合焓ΔHmix和混合熵ΔSmix.结合临界冷却速率,归纳出典型金属玻璃形成液体的热力学特性,并提出基于原子尺寸、元素组成以及元素之间混合焓等参数的形成大块金属玻璃的成分判定方法.结果表明,当ΔHmix<-15kJ·mol-1且ΔSmix>0·6J·K-1mol-1时,合金易于形成大块金属玻璃.金属玻璃的临界冷却速率Rc具有明显的尺寸效应,其值与熔体的ΔSmix值呈指数关系,可以用Rc=42·24×104exp(-13·91ΔSmix)+19·66粗略判断.运用该方法成功设计并制备出远离原有Zr基大块金属玻璃形成区域(55at%—65at%Zr)的Zr40Al10Ni15Cu35和四元Fe-B基Fe53Co5Nd12B30大块金属玻璃.On the basis of analyzing the thermodynamic model of regular melt, the mixing enthalpy △H^mix and the mixing entropy △S^mix of typical metallic glass melts were calculated. The distribution of △H^mix vs.△S^mix for typical metallic glasses was generalized, and a strategy for pinpointing metallic glass formers has been proposed by combining the critical cooling rate Rc based on the atomic intrinsic characteristics of the alloys including atom size, composition, and mixing enthalpy of binary systems among the components. On the condition of △S^mix greater than 0.6 J·K^-1 mol^-1 and △H less than - 15 kJ· mol^-1 , the alloy tends to form a bulk metallic glass（BMG）. It shows that Rc is intimately related with △S^mix, and can be expressed as Rc = 4-2.24 × 10^4 exp（ - 13.91 △S^mix） ＋ 19.66. Two new glass formers, Zr40Al10Nil5 Cu35, located far from the glass rosining area of the existing Zr-Al-Ni-Cu BMGs with a content of 55at%-65at% zirconium, and Fe53 Co5Nd12 B30 of quaternary Fe-B-based BMG, were successfully prepared with this approach.

关 键 词：混合焓 混合熵 大块金属玻璃 玻璃形成能力 

分 类 号：O482.2[理学—固体物理]