摘要
研究贝氏体碳化物的形成规律具有重要理论意义。实验观察表明,在有碳化物贝氏体中只有θ-渗碳体和ε-Fe_(2.4)C,没有特殊合金碳化物。贝氏体碳化物呈短棒状,沿着BF的长轴方向分布(上贝氏体)或与贝氏体铁素体片呈角度分布(下贝氏体),分布于贝氏体铁素体片条内部,即贝氏体碳化物(BC)被贝氏体铁素体包围。贝氏体碳化物来源于贝氏体铁素体片条之间的富碳奥氏体或贝氏体亚单元间的富碳奥氏体。碳化物在BF/γ相界面上形核,并且向奥氏体内部长大。贝氏体碳化物的形核-长大是依靠界面原子非协同热激活迁移实现位移,铁原子和替换原子在BC/BF相界面和Bc/γ相界面上热激活跃迁,BC向奥氏体内长大,也可以向铁素体内长大。
It is of great significance in theory to study the formation of bainite carbide.The experimental observation shows that there is only θ-cementite or ε-Fe（2.4）C but no special alloy-carbides in bainite with carbide.The bainite carbides present in short-bar shape and distribute along the long axis direction of the bainite ferrite in upper bainite or interiorly the bainite ferrite in lower bainite showing a certain angle between the carbides and the principal axis of the bainite ferrites.The bainite carbides derive from the carbon-rich austenite among the bainite ferrite slices or the bainite subunits.The carbides nucleate in the phase interface between bainite ferrite and austenite and grow towards the austenite grain interior.The nucleation and growth of the bainite carbides depend on the non-synergic thermal activation transition of the interfacial atoms.The thermal activation transition of the iron and replace atoms conducts both along the phase interface between bainite carbide and bainite ferrite and along the phase interface between bainite carbide and austenite.The carbides can grow towards the austenite grain interior and towards the ferrite interior too.
作者
刘宗昌
计云萍
任慧平
LIU Zong-chang JI Yun-ping REN Hui-ping(Analysical and Testing Center, Inner Mongolia University of Science and Technology, Baotou Inner Mongolia 014010, China Material and Metallurgy School, Inner Mongolia University of Science and Technology, Baotou Inner Mongolia 014010, China)
出处
《热处理技术与装备》
2017年第4期1-7,共7页
Heat Treatment Technology and Equipment
基金
国家自然科学基金(51261018)
