Feng Ruicheng, Song Wenyuan, Li Haiyan, Qi Yongnian, Qiao Haiyang, Li Longlong
School of Mechanical and Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
Key Laboratory of Digital Manufacturing Technology and Application, Ministry of Education, Lanzhou University of Technology, Lanzhou 730050, China.
Materials (Basel). 2018 Jun 15;11(6):1025. doi: 10.3390/ma11061025.
In this paper, molecular dynamics simulations are performed to study the annealing process of γ-TiAl alloy with different parameters after introducing residual stress into prepressing. By mainly focusing on the dynamic evolution process of microdefects during annealing and the distribution of residual stress, the relationship between microstructure and residual stress is investigated. The results show that there is no phase transition during annealing, but atom distortion occurs with the change of temperature, and the average grain size slightly increases after annealing. There are some atom clusters in the grains, with a few point defects, and the point defect concentration increases with the rise in temperature, and vice versa; the higher the annealing temperature, the fewer the point defects in the grain after annealing. Due to the grain boundary volume shrinkage and and an increase in the plastic deformation of the grain boundaries during cooling, stress is released, and the average residual stress along Y and Z directions after annealing is less than the average residual stress after prepressing.
本文通过分子动力学模拟研究了预压引入残余应力后不同参数的γ-TiAl合金的退火过程。主要关注退火过程中微观缺陷的动态演变过程以及残余应力的分布，研究了微观结构与残余应力之间的关系。结果表明，退火过程中无相变，但原子畸变随温度变化而发生，退火后平均晶粒尺寸略有增加。晶粒内存在一些原子团簇，有少量点缺陷，点缺陷浓度随温度升高而增加，反之亦然；退火温度越高，退火后晶粒内的点缺陷越少。由于冷却过程中晶界体积收缩以及晶界塑性变形增加，应力得以释放，退火后沿Y和Z方向的平均残余应力小于预压后的平均残余应力。
