Zhang Haichao, Chen Yinli, Wang Xufeng, Li Huirong, Li Yungang
Department College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, China.
Department Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100089, China.
Materials (Basel). 2021 Sep 2;14(17):5029. doi: 10.3390/ma14175029.
The molecular dynamics (MD) simulation method was used to explore the impact of vacancy concentration (0 at%, 0.1 at% and 0.2 at%) on the diffusion and precipitation rate of Cu atoms in the Fe-3.5Cu alloy and the growth of Cu precipitation during the aging process of the alloy. The mechanism of the influence of Cu precipitation relative to the tensile properties of Fe-3.5Cu alloy was investigated. The results showed that the presence of vacancies will promote the diffusion and precipitation of Cu atoms in the Fe-3.5Cu alloy, but the diffusion and precipitation rate of Cu atoms does not always increase with the increase in vacancies. In the alloy containing 0.2 at% vacancies, the diffusion and precipitation rate of Cu atoms is lower than that in the alloy containing 0.1 at% vacancies. During the aging process, when the alloy contains no vacancies, no Cu precipitates will be produced. In the alloy containing 0.1 at% vacancies, the size of the Cu precipitates produced is larger than the size of the Cu precipitates produced in the alloy containing 0.2 at% vacancies, but the number of precipitates is less than that in the alloy with 0.2 at% vacancies. During the tensile process, the Cu precipitates will promote early occurrence of phase transition of the internal crystal structure in the Fe-3.5Cu alloy system, and lead to the generation of vacancy defects in the system, thus weakening the yield strength and strain hardening strength of the alloy.
采用分子动力学（MD）模拟方法，研究空位浓度（0原子百分比、0.1原子百分比和0.2原子百分比）对Fe-3.5Cu合金中Cu原子扩散和析出速率以及合金时效过程中Cu析出相生长的影响。研究了Cu析出相对Fe-3.5Cu合金拉伸性能的影响机制。结果表明，空位的存在会促进Fe-3.5Cu合金中Cu原子的扩散和析出，但Cu原子的扩散和析出速率并不总是随空位增加而增大。在含有0.2原子百分比空位的合金中，Cu原子的扩散和析出速率低于含有0.1原子百分比空位的合金。在时效过程中，当合金不含空位时，不会产生Cu析出相。在含有0.1原子百分比空位的合金中，产生的Cu析出相尺寸大于含有0.2原子百分比空位的合金中产生的Cu析出相尺寸，但析出相数量少于含有0.2原子百分比空位的合金。在拉伸过程中，Cu析出相会促进Fe-3.5Cu合金体系内部晶体结构的相变提前发生，并导致体系中产生空位缺陷，从而削弱合金的屈服强度和应变硬化强度。
