For the application of the time-temperature superposition principle a suitable relation is needed to describe the time-temperature shift factor a. Therefore, the Arrhenius equation is widely used due to its simple for...For the application of the time-temperature superposition principle a suitable relation is needed to describe the time-temperature shift factor a. Therefore, the Arrhenius equation is widely used due to its simple form and often leads to suitable results. Where, the Arrhenius equation presents a linear relation for the temperature-dependent shift factor in logarithmic scale ln（α） with the absolute inverse temperature （1/θ）. However, in cases with a large temperature range which eventually include more complex reaction processes, the functional relation between ln（α） and （1/θ） is nonlinear in the ＇Arrhenius plot＇. In those cases, the monotone change of the nonlinear range in the ＇Arrhenius plot＇ can be interpreted as a transient range between two approximately linear or constant regions. An extended application of the modified Arrhenius equation from Nakamura （1989） is presented in this study for this transient range. The introduced method was applied to describe the time-temperature equivalence in the relaxation analysis of restoring seal force of metal seals, which are used in lid-systems of transport and interim storage casks for radioactive materials. But, the method is widely valid and can be used for different objectives which are characterized by thermorheologically simple behavior with nonlinear sensitivity to inverse temperature.展开更多
The accelerating factor （AF） method is a simple and appropriate way to investigate the atomic long-time deep diffusion at solid-solid interface. In the framework of AF hyperdynamics （HD） simulation, the relationsh...The accelerating factor （AF） method is a simple and appropriate way to investigate the atomic long-time deep diffusion at solid-solid interface. In the framework of AF hyperdynamics （HD） simulation, the relationship between the diffusion coefficient along the direction of z-axis which is normal to the Mg/Zn interface and temperature was investigated, and the AF＇s impact on the diffusion constant （D0） and activation energy （Q^＊） was studied. Then, two steps were taken to simulate the atomic diffusion process and the formation of new phases： one for acceleration and the other for equilibration. The results show that： the Arrhenius equation works well for the description of Dz with different accelerating factors; the AF has no effect on the diffusion constant Do in the case of no phase transition; and the relationship between Q＊ and Q conforms to Q^＊=Q/A. Then, the new Arrhenius equation for AFHD is successfully constructed as Dz=Doexp[-Q/（ART）]. Meanwhile, the authentic equilibrium conformations at any dynamic moment can only be reproduced by the equilibration simulation of the HD-simulated configurations. Key words： accelerating factor method; Arrhenius equation; two-steps scheme; Mg/Zn interface; hyperdynamic simulation展开更多
文摘For the application of the time-temperature superposition principle a suitable relation is needed to describe the time-temperature shift factor a. Therefore, the Arrhenius equation is widely used due to its simple form and often leads to suitable results. Where, the Arrhenius equation presents a linear relation for the temperature-dependent shift factor in logarithmic scale ln（α） with the absolute inverse temperature （1/θ）. However, in cases with a large temperature range which eventually include more complex reaction processes, the functional relation between ln（α） and （1/θ） is nonlinear in the ＇Arrhenius plot＇. In those cases, the monotone change of the nonlinear range in the ＇Arrhenius plot＇ can be interpreted as a transient range between two approximately linear or constant regions. An extended application of the modified Arrhenius equation from Nakamura （1989） is presented in this study for this transient range. The introduced method was applied to describe the time-temperature equivalence in the relaxation analysis of restoring seal force of metal seals, which are used in lid-systems of transport and interim storage casks for radioactive materials. But, the method is widely valid and can be used for different objectives which are characterized by thermorheologically simple behavior with nonlinear sensitivity to inverse temperature.
基金Project (2012CB722805) supported by the National Basic Research Program of ChinaProjects (50974083, 51174131) supported by the National Natural Science Foundation of China+1 种基金Project (50774112) supported by the Joint Fund of NSFC and Baosteel, ChinaProject(07QA4021) supported by the Shanghai "Phosphor" Science Foundation, China
文摘The accelerating factor （AF） method is a simple and appropriate way to investigate the atomic long-time deep diffusion at solid-solid interface. In the framework of AF hyperdynamics （HD） simulation, the relationship between the diffusion coefficient along the direction of z-axis which is normal to the Mg/Zn interface and temperature was investigated, and the AF＇s impact on the diffusion constant （D0） and activation energy （Q^＊） was studied. Then, two steps were taken to simulate the atomic diffusion process and the formation of new phases： one for acceleration and the other for equilibration. The results show that： the Arrhenius equation works well for the description of Dz with different accelerating factors; the AF has no effect on the diffusion constant Do in the case of no phase transition; and the relationship between Q＊ and Q conforms to Q^＊=Q/A. Then, the new Arrhenius equation for AFHD is successfully constructed as Dz=Doexp[-Q/（ART）]. Meanwhile, the authentic equilibrium conformations at any dynamic moment can only be reproduced by the equilibration simulation of the HD-simulated configurations. Key words： accelerating factor method; Arrhenius equation; two-steps scheme; Mg/Zn interface; hyperdynamic simulation
