Fuxing YIN
,
Nanju GU (Hebei Institute of Technology
,
Tianin 300132
,
China)T.Shigematsu
,
N.Nakanishi(Faculty of Science
,
Konan University Kobe 658
,
Japan)Y.Osawa
,
A.Sato(National Research Institute of Metals
,
Tsukuba 305
,
Japan)
材料科学技术（英文）
Amorphization of Mn carbides by rapid quenching method has been proved to be unsuccessful.By mechanical milling in the present work, amorphous phases have been formed in the perovskitetype Mn3AlC compound. The transformation process from crystalline to amorphous phase was found to be milling time controlled, and 10 h is a critical period for the macroscopically single amorphous phase to form. It has been clarified that the redistribution of C atoms is an instinctive factor for amorphous phase to nucleate, and the atomic configuration in the amorphous phase is changed much in longer milling that different crystallizing behaviours have been caused. With X-ray diffraction and differential scanning calorimetry (DSC) results, an atomic configuration transition model is considered for the structures of the amorphous phases changed during milling.
关键词:
庄厚龙
,
彭平
,
周惦武
,
刘金水
稀有金属材料与工程
采用第一原理赝势平面波方法--CASTEP程序计算了4种B2型Y基金属间化合物YX(X=Ag,Cu,In,Rh)的部分弹性性质,计算结果与文献报道值基本一致.通过Pugh定律、Cauchy压力和泊松比等经验判据,分析并预测了它们的脆性/延性,其延性高低次序为:YRh＞YAg＞YCu＞YIn.电子结构分析表明:这4种金属间化合物良好的延性源于其较强的金属键,而不同程度的Y(d)-X(p)电子杂化则导致了其延性的差异.YIn中因In的p电子较多,杂化程度高,共价键方向性强,因而延展性最低,而YRh则由于存在Y(d)-Rh(d)电子间强的相互作用,增强了其金属键作用,因而延性最好.
关键词:
Y基金属间化合物
,
脆性/延性
,
第一原理
,
电子结构
