Effects of Al on the precipitation of B2 Cu-rich particles in Fe-Cu ferritic alloy: Experimental and theoretical study
Effects of Al on the precipitation of B2 Cu-rich particles in Fe-Cu ferritic alloy: Experimental and theoretical study
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Al对Fe-Cu铁素体合金中B2富Cu颗粒析出的影响：实验与理论研究
DOI：
10.1016/j.jallcom.2020.156386
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发表时间：
2020
影响因子：
6.2
通讯作者：
Ren Huiping
中科院分区：
文献类型：
--
作者：
Wang Haiyan;Gao Xueyun;Chen Shuming;Li Yiming;Wu Zhongwang;Ren Huiping
纳米级Cu析出相的析出动力学和稳定性的基本机制是开发超高强度低碳铁素体钢的关键。采用第一性原理计算和分子动力学模拟相结合的实验方法，研究了Al对Fe-Cu基钢中富B2 Cu析出相的形成和稳定化的影响。随着时效时间的延长，B2结构的富Cu颗粒以立方对立方、共格的关系在铁素体基体中析出，Al的加入导致了相对较高的沉淀硬化效果。第一性原理计算表明，亚稳B2 FeCu相具有较高的混合能和较小的晶格失配，Al的加入降低了B2相的混合能，B2结构的Fe（CuAl）化合物具有较小的晶格失配.为了更好地理解Al对富Cu颗粒演化过程的影响，有必要在原子尺度上研究等温回火过程中Cu原子的迁移和聚集过程。为此，我们首先采用基于从头算的力匹配方法建立了Fe-Cu-Al三元体系的相互作用势，然后采用分子动力学方法研究了Fe-Cu-Al三元体系中Cu团簇的形成和演化.模拟结果表明，Al的加入促进了Cu原子的聚集，这是由于Cu原子与Al原子之间的相互吸引作用提高了富Cu沉淀的形核速率。
The fundamental mechanism of the precipitation kinetics and stability of nano-sized Cu-precipitates are crucial to the development of ultra-high strength low carbon ferritic steels. The effects of Al on the formation and stabilization of B2 Cu-rich precipitates in Fe–Cu based steels were studied using experimental method combining the first-principles calculations and molecular dynamics simulations. With increasing aging time, the Cu-rich particles with B2 structure precipitated in the ferritic matrix with cube-on-cube and coherent relationship, and Al addition leads to a relatively higher precipitation hardening effect. The first-principle calculations indicate that the metastable B2 FeCu phase has relatively higher mixing energy and small lattice mismatch with the ferritic matrix, and the addition of Al leads to the lower mixing energy of B2 precipitates and the B2 structure Fe(CuAl) compound possesses more smaller lattice mismatch with ferritic matrix. To better understanding the effect of Al on the evolution process of Cu-rich particles, it is essential to investigate the migration and clustering process of Cu atoms during the isothermal tempering at the atomic scale. To this end, we first developed a new interatomic potential of Fe–Cu–Al using the force-matching method based onab initiocalculations, then the formation and evolution of Cu clusters in the Fe–Cu–Al ternary were studied using molecular dynamics method with the new EAM potential. The simulation results indicate that Al addition promotes the clustering of Cu atoms due to the attractive interaction between Cu and Al atoms which enhances nucleation rate of the Cu-rich precipitates.