贝氏体钢时效处理富Cu团簇析出特点及其第一性原理计算  

Precipitation Characteristics and First-principles Calculation of Cu-Rich Clusters in Bainite Steel Aged Treatment

作　　者：杨劼[1] 任慧平[1] 王海燕[1] 高雪云[1] 刘宗昌[1] YANG Jie;REN Huiping;WANG Haiyan;GAO Xueyun;LIU Zongchang(College of Materials and Metallurgy,Inner Mongolian University of Science and Technology,Baotou 014010,Inner Mongolia,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《材料导报》2024年第14期232-238,共7页Materials Reports

基　　金：国家自然科学基金(51764047)。

摘　　要：研究低碳贝氏体钢(15Cr12CuSiMoMn)时效处理过程中富Cu团簇的析出演变特点,并基于第一性原理计算,采用特殊准随机结构(Special quasirandom structures,SQS)、Solid-State Nudged Elastic Band(SSNEB)方法构建Fe-Cu二元体系的无序固溶体结构模型,模拟计算相变能量路径,分析并表征析出相析出演变规律与模拟计算之间的相互联系。结果表明,实验钢在指定温度(500℃)进行时效热处理,时效处理各阶段实验钢中弥散析出约2.6~53 nm的富Cu团簇,以共格、非共格状态存在于基体中,经模拟计算,BCC-Cu向9R-Cu转变过程中需在开始阶段克服8.9 meV的能垒,之后从9R-Cu向孪晶FCC-Cu+9R-Cu结构转变过程中需要克服4.9 meV的能垒,非稳态BCC富Cu团簇与稳定态的FCC Cu之间具有0.14 eV/atom的形成能差,当Cu含量超过21.6%(原子分数)后,富Cu团簇从BCC结构不断向稳定的纯FCC-Cu结构演变。从能量角度分析了富Cu团簇析出倾向,解释了富Cu团簇的析出惯序,有利于优化贝氏体组织,为含Cu贝氏体沉淀钢的深入研究及相关领域的开发拓展提供理论参考依据。The evolution characteristics of Cu-rich clusters in the aging process of low carbon bainitic steel(15Cr12CuSiMoMn)were studied.Based on the calculation of first principles,the disordered solid solution structure model of Fe-Cu binary system was constructed by SQS,SSNEB method,and the energy path of phase transition was simulated.The relationship between the evolution rule of precipitated phase and the simulation calculation was analyzed and characterized.The results show that the experimental steel is aged at a specified temperature(500℃),and about 2.6—53 nm of Cu-rich clusters are separated from the experimental steel at each stage of aging treatment,and exist in the matrix in coherent and non-coherent states.According to the simulation calculation,the energy barrier of 8.9 meV should be overcome during the transition from BCC-Cu to 9R-Cu,and 4.9 meV should be overcome during the transition from 9R-Cu to twin FCC-Cu+9R-Cu.There is a 0.14 eV/atom difference between the transient BCC Cu clusters and the stable FCC Cu clusters.When the Cu content exceeds 21.6at%,the Cu rich clusters evolve from BCC structure to stable FCC-Cu structure.By analyzing the precipitation tendency of Cu-rich clusters from the perspective of energy,the precipitation habit sequence of Cu-rich clusters is explained,which is conducive to the optimization of bainite structure,and provides a theoretical reference for the further study of Cu-containing bainite precipitation steel and the development of related fields.

关 键 词：15Cr12CuSiMoMn钢 富Cu团簇 时效处理 结构转变 

分 类 号：TG142.1[一般工业技术—材料科学与工程]