Simulation of He behavior in bcc Fe on heating

Abstract

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—1298 K. The simulation results show that the temperature influence on He behavior can be divided into four different stages: 1）298—598 K；2）598—798 K；3）798—998 K；4）998—1298 K. 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 1298 K, the average number of He atoms is almost equal to that at room temperature, and almost no He escapes from Fe grains.