After a standard heat treatment,the microstructural evolution with time during isothermal aging at 850°C and its effect on the creep rupture properties of the Ni-base superalloy M4706 at 870°C and 370 MPa ar...After a standard heat treatment,the microstructural evolution with time during isothermal aging at 850°C and its effect on the creep rupture properties of the Ni-base superalloy M4706 at 870°C and 370 MPa are investigated.It is found that as the aging time increases from 0 to 5000 h,the average diameter of coarseγ′increases from 241 to 484 nm,and the distribution of the carbides at grain boundaries changes from discontinuous to continuous.Moreover,experimental observations on the microstructures of all the crept specimens reveal that dislocation bypassing controls the creep deformation.Thus,it is concluded that the transitions in the microstructures result in the degeneration of the creep rupture properties of the experimental alloy with aging time.展开更多
Tight-binding electron-ion dynamics of carbon chains pumped by intense laser pulses are performed to study the interactions between monatomic carbon chains and lasers.Laser-induced distortions of carbon chains,which a...Tight-binding electron-ion dynamics of carbon chains pumped by intense laser pulses are performed to study the interactions between monatomic carbon chains and lasers.Laser-induced distortions of carbon chains,which are enhanced by a long wavelength laser,are investigated.The carbon chains with a strong laser beam focused on one terminal are simulated to study the disturbance of electronic states.By the superposition of delocalized π band states,the disturbance propagates from the illuminated area to the non-illuminated area in a velocity ofabout 106 m/s at 0 K,and this velocity is weakened at room temperature due to the localization effect of thermal fluctuation.展开更多
基金Project(2018BSHQYXMZZ32)supported by the Postdoctoral Science Foundation of Shaanxi Province of ChinaProject(20192109)supported by the State Key Laboratory for Mechanical Behavior of Materials,ChinaProjects(2017M623213,2018M633487)supported by the Postdoctoral Science Foundation of China
文摘After a standard heat treatment,the microstructural evolution with time during isothermal aging at 850°C and its effect on the creep rupture properties of the Ni-base superalloy M4706 at 870°C and 370 MPa are investigated.It is found that as the aging time increases from 0 to 5000 h,the average diameter of coarseγ′increases from 241 to 484 nm,and the distribution of the carbides at grain boundaries changes from discontinuous to continuous.Moreover,experimental observations on the microstructures of all the crept specimens reveal that dislocation bypassing controls the creep deformation.Thus,it is concluded that the transitions in the microstructures result in the degeneration of the creep rupture properties of the experimental alloy with aging time.
文摘Tight-binding electron-ion dynamics of carbon chains pumped by intense laser pulses are performed to study the interactions between monatomic carbon chains and lasers.Laser-induced distortions of carbon chains,which are enhanced by a long wavelength laser,are investigated.The carbon chains with a strong laser beam focused on one terminal are simulated to study the disturbance of electronic states.By the superposition of delocalized π band states,the disturbance propagates from the illuminated area to the non-illuminated area in a velocity ofabout 106 m/s at 0 K,and this velocity is weakened at room temperature due to the localization effect of thermal fluctuation.
