First-Principles Study of the Influence of Lattice Misfit on the Behavior and the Ductility Effect o

• 作 者: Yuxi Wu Jia Guo Jieshan Hou Wanglin Zhang Renzhong Huang Xianguo Liu Xiufang Ma Qianfeng Zhang
• 机 构: Institute of Molecular Engineering and Applied Chemistry,Anhui University of Technology,Shenyang Nat
• 出 处: Acta Metallurgica Sinica(English Letters)
• 发表日期: 2014年01期
• 关键词: anomalous ductility disappear preference segregation contained contributing clar

Two Ni/Ni_3Al-interface-contained cluster models with/without lattice misfit are studied by first-principles method to clarify the debates about the segregation behaviors of Hafnium(Hf) and explore the influence of lattice misfit on the ductility effect of Hf.It is found that though Hf prefers to substitute Al rather than Ni in Ni_3Al phase within most of the investigated misfit range,its stronger preferring to Ni phase than Ni_3Al phase makes it impossible to go into Ni_3Al phase to occupy Al site in Ni-Ni_3Al alloys.Bond order analysis in Hf-free case shows that lattice misfit has different effects on the Griffith work of interfacial cleavage 2_(γint)/E and the maximum theoretical shear stress τ_(max) of Ni and Ni_3Al,contributing to the existence of anomalous strength-temperature phenomena in Ni_3Al alloys.However,the addition of Hf will make the2_(γint)/E(or τ_(max)) of both Ni_3Al and Ni decrease(or increase) with lattice misfit,indicating that the addition of Hf may make the anomalous strength-temperature relationship in Ni_3Al region disappear locally.

Two Ni / Ni_3Al-interface-contained cluster models with / without lattice misfit are studied by first-principles method to clarify the debates about the segregation behaviors of Hafnium (Hf) and explore the influence of lattice misfit on the ductility effect of Hf.It is found that though Hf prefers to substitute Al rather than Ni in Ni_3Al phase within most of the investigated misfit range, its reinforcement preferring to Ni phase than Ni_3Al phase makes it impossible to go into Ni_3Al phase to occupy Al site in Ni-Ni_3Al alloys. Bond order analysis in Hf-free case shows that lattice misfit has different effects on the Griffith work of interfacial cleavage 2_ (γint) / E and the maximum theoretical shear stress τ_ (max) of Ni and Ni_3Al, contributing to the existence of anomalous strength The addition of Hf will make the2_ (γint) / E (or τ_ (max)) of both Ni_3Al and Ni decrease (or increase) with lattice misfit, indicating that the addition of Hf may make the anomalous strength-temperature relationship in Ni_3Al region disappear locally.