Senying LIU
,
Rongze HU
,
Dongliang ZHAO and Chongyu WANG(Central Iron and Steel Research Institute
,
Beijing
,
100081
,
China)(To whom correspondence should be addressed)Ping LUO(National Research Cent or Certified Materials
,
Beijing
,
100013
,
China)Zhongjie P
材料科学技术（英）
By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.
关键词:
Senying LIU
,
Dongliang ZHAO
,
Rongze HU
,
Chongyu WANG
,
Ping LUO
材料科学技术（英）
The bonding characteristics of (0001)α2‖(111)γ interface in two-phase TiAl alloy have been investigated with the recursion method. The results of bond order integral and interaction energy between atoms are presented. The effects of B on atoms bonding both in constituent phase and at the α2/γ interface have been studied. The correlation between the mechanical properties of the alloy and the bonding at the interface has been discussed. The results suggest that B segregation to the interface benefits the ductility. This is supported by therelated experiment.
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