温度对bcc铁中He行为影响的模拟研究

Simulation of He behavior in bcc Fe on heating

温度对bcc铁中的He行为有重要的影响,基于bcc晶格的晶格动力学蒙特卡罗(Lattice Kinetic Monte Carlo,LKMC)方法,模拟研究了298—1298K范围内温度对bcc铁中He行为的影响.结果表明:温度对bcc铁中He行为的影响可以分为4个阶段:(1)298—598K,(2)598—798K,(3)798—998K,(4)998—1298K.第一阶段随着温度的增加,晶粒内He原子浓度略有降低,但He泡中平均He原子个数迅速增加;第二阶段随着温度的增加,晶粒内的He原子浓度迅速降低,但He泡中平均He原子个数几乎不变;第三阶段随着温度的增加,晶粒内的He原子浓度和He泡中平均He原子个数均迅速减少;第四阶段随着温度的增加,晶粒内He原子浓度以及He泡中平均He原子个数均有所增加,到1298K时,晶粒内He原子浓度与室温时相近,几乎没有He原子从铁晶粒内逃逸出.模拟结果与文献正电子湮灭实验结果有很好的吻合.

Temperature is an important factor for the behavior of He in metals.In this paper,we write a LKMC（lattice kinetic Monte Carlo）program to simulate the behavior of He in bbc Fe under the temperature range of 298—1298K.The simulation results show that the temperature influence on He behavior can be divided into four different stages：1）298—598K;2）598—798K;3）798—998K;4）998—1298K.In the first stage：with the increase of temperature,the concentration of He in the grain has a little decrease,but the average number of He in He bubbles increases greatly;In the second stage,with the increase of temperature,the concentration of He in the grain decrease rapidly,but the average size of He bubbles almost keeps constant.In the third stage,with the increase of temperature,the concentration of He in grains and the average numbers of He in He bubbles both decrease rapidly.In the third stage：with the increase of temperature,the average numbers of He atoms in the grain and the average size of He bubbles both increase.At 1298K,the average number of He atoms is almost equal to that at room temperature,and almost no He escapes from Fe grains.