ABSTRACT

By adding alloying elements in Pt, the solid-solution strengthening is extensively used to improve the mechanical properties of Pt-based alloys, one of the most promising high-temperature materials due to its higher melting point. Yet the microscopic mechanism of the alloying effects on the mechanical properties of Pt is unclear. Based on a systematic study of the influence of alloying elements on the generalised stacking fault energy (GSFE) of Pt with first-principles calculations, the alloying effects on deformation mechanism and ductility of Pt are explored in this study. It is found that the alloying elements such as Y, Hf, Mo tend to decrease the intrinsic stacking fault energy (${\gamma }_{isf}$) of Pt and improve its ductility, while Ru, Rh, Ir tend to increase the ${\gamma }_{isf}$ and result in brittleness. The analysis of the electron localisation function (ELF) and density of states (DOS) indicates that the weaker or enhancer bonding between Pt atom and alloying atom at the local stacking fault area is responsible for the variation of the GSFEs, which further affects the mechanical properties of Pt-based alloys.

摘要

通过在Pt中添加合金元素，固溶强化被广泛用于改善Pt基合金的机械性能，Pt基合金由于其较高的熔点而成为最有希望的高温材料之一。合金化对Pt力学性能影响的微观机理尚不清楚。基于第一性原理，系统地研究了合金元素对Pt的广义堆垛层错能（GSFE）的影响，探讨了合金化对Pt变形机理和延性的影响。发现诸如Y，Hf，Mo之类的合金元素倾向于降低固有堆垛层错能（${\gamma }_{\mathrm{一世}sF}$）并提高其延展性，而Ru，Rh，Ir则倾向于增加Pt ${\gamma }_{\mathrm{一世}sF}$并导致脆性。对电子本地化函数（ELF）和态密度（DOS）的分析表明，在局部堆垛层错区域Pt原子与合金原子之间的弱键或增强键是GSFE的变化的原因，这进一步影响了机械性能。铂基合金的性能。