温度对fcc铁中氦行为的影响研究

Simulation of temperature effect on helium behavior in fcc Fe

温度对fcc铁中的氦行为具有重要的影响,编写了居于fcc晶格的面向对象动力学蒙特卡罗程序(Object Kinetic Monte Carlo),采用该程序结合分子动力学(MID)方法对fcc铁中的氯行为进行多尺度模拟,研究了温度对fcc铁中氯行为的影响,给出了不同温度退火过程中氯行为的原子细节.模拟结果表明引入一定量的非热平衡空位可以使模拟结果与文献实验结果有非常好的吻合;室温至1073 K,温度对氯行为影响可以分为四个阶段:第一阶段,298～473 K,正电子长寿命随退火温度增加略有减少,这主要由于非热平衡空位浓度降低;第二阶段,473～673 K,正电子长寿命随退火温度增加而增加,主要由于晶粒内平均氦泡尺寸增加;第三阶段,673～873 K,正电子长寿命随退火温度增加而迅速减少,主要是由于氯泡的平均尺寸减小和晶粒内的空位浓度降低;第四阶段,873～1073 K,正电子长寿命随退火温度增加而迅速增加,与晶粒内氦泡的平均尺寸变大,且空位浓度随温度的增加而指数增加有关.

Temperature has inportamt influence on the behavior of helium in fcc steels. A OKMC（Object Kinetic Monte Carlo） code was wrote to simulate the behavior of helium in fcc Fe under different anneal temperatures,evolution of defects during anneal was proposed at atom level. The simulation results show that experiment results can be explained well by introducing some non-thermal equilibrium vacancy. The temperature influence on Helium behavior can be divided into four different stages：1）298-473 K; 2）473 -673 K; 3）673-873 K; 4）873-1073 K. In the first stage：with the increase of temperature,the concentration of non-thermal equilibrium vacancy decrease; In the second stage： with the increase of temperature,the average size of He bubbles increase ; In the third stage：with the increase of temperature, the average size of helium in grains and the concentration of non-thermal equilibrium vacancy both decrease rapidly;In the last stage： with the increase of temperature, the average size of helium in grains and the concentration of non-thermal equilibrium vacancy both increase.