2.25Cr1Mo钢中磷原子偏聚引起的回火脆性分子动力学模拟研究  

Molecular Dynamics Simulation Study on Temper Embrittlement Caused by Segregation of Phosphorus Atoms in 2.25Cr1Mo Steel

作　　者：杜振国 疏小勇 戴韬 赵建平[1] DU Zhenguo;SHU Xiaoyong;DAI Tao;ZHAO Jianping(School of Mechanical and Power Engineering,Nanjing Tech University,Nanjing Jiangsu 211816,China)

机构地区：[1]南京工业大学机械与动力工程学院,江苏南京211816

出　　处：《上海金属》2025年第2期87-94,共8页Shanghai Metals

基　　金：国家重点研发计划(2021YFC3001805);江苏省研究生科研与实践创新计划(KYCX22_1376)。

摘　　要：采用平衡偏聚理论与分子动力学模拟相结合的方法研究了服役不同时间的2.25Cr1Mo钢中Σ3(111)晶界拉伸和裂纹扩展行为。结果表明:磷原子在晶界偏聚使晶界无序原子比例增加,从而拉伸和断裂过程中晶界原子的运动受阻,降低了晶界结合力和晶界裂纹尖端塑性,导致裂纹尖端钝化不显著及裂纹扩展加快;随着晶界磷原子浓度的增大,理论抗拉强度和Ⅰ型断裂韧度先线性下降后快速下降;随着服役时间的延长,前28000 h内理论抗拉强度和Ⅰ型断裂韧度下降较快,随后缓慢下降,服役436000 h后又快速下降。Tensile and crack propagation behaviors ofΣ3(111)grain boundary in 2.25Cr1Mo steel serviced for different lengths of time were investigated via a combination of equilibrium segregation theory with molecular dynamics simulation.The results indicated that(a)the segregation of P atoms at grain boundary increased the proportion of disordered atoms,therefore the motion of atoms at grain boundary during tension and fracture was hindered,and the bonding force of grain boundary and plasticity of crack tips at grain boundary were reduced,leading to insignificant blunting of crack tips and even rapider propagation of crack;(b)with the increase of P atom concentration at grain boundary,the theoretical tensile strength and I-mode fracture toughness decreased linearly at first and then decreased fast;(c)as the service time increased,the theoretical tensile strength and I-mode fracture toughness decreased faster at first within first 28000 h and then decreased slow,and again decreased fast after being served for 436000 h.

关 键 词：回火脆性 分子动力学 P 原子晶界偏聚 理论抗拉强度 Ⅰ型断裂韧度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]