V-N微合金化抗震钢筋铁素体中V(C,N)析出行为分析  

Analysis on V(C,N) Precipitated Behaviors in Ferrite of V-N Microalloyed Anti-seismic Rebars

作　　者：吕煜坤[1] 盛光敏[1] 尹丽晶[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044

出　　处：《材料工程》2014年第11期43-49,共7页Journal of Materials Engineering

基　　金：国家科技支撑计划项目(2007BAE30B05)

摘　　要：采用回火硬度法研究了两种不同V,N含量的抗震钢筋回火等温过程组织及显微硬度变化规律,根据J-M-A(Johnson-Mehl-Avrami)理论定量计算了V(C,N)在铁素体中的析出热动力学,并与实验所测PTT(析出-温度-时间)曲线进行对比。透射电镜下观察了V(C,N)沉淀析出规律。结果表明,由于大量弥散的第二相颗粒的作用,V-N微合金化钢筋(0.04V-0.0135N)的回火组织比V微合金化钢筋(0.076V-0.0055N)更加均匀细小。回火硬度法测得两种材料的PTT曲线与计算所得吻合,V微合金化钢筋呈"C"型且在670℃左右的鼻温区析出动力学加快,V-N微合金化钢筋是一单调曲线,这主要考虑N含量的影响。本次实验同时观察到纤维状碳化物,V(C,N)在过饱和铁素体中相间析出以及位错线析出,并就其形成机制进行讨论。Tempering hardness method for two different V, N content of anti-seismic reinforcing steel bars were studied on microstructure of tempering isothermal process and variation regulars of microhardness. V (C, N) precipitation theoretical thermo-kinetic in ferrite was quantitatively determined according to the J-M-A (Johnson-Mehl-Avrami) theory, and compared with the experimental PTT curve. V (C, N) precipitation rule was observed by transmission electron microscopy. The results show that due to the effects of abundant and dispersed second phase particles, the tempering microstructure of V-N microalloyed rebar (0.04V-0.0135N) is more uniform and fine than V microalloyed rebar (0.076V-0.0055N). The PTT curve which is attained from variety microhardness of two materials are consistent with the calculation result. V microalloyed rebar presents a 'C' shape and its precipitation kinetics is accelerated in the nosal temperature zone about 670, V-N microalloyed rebar is monotonous curve, which is mainly affected by N content. Also in this experiment fibrous carbides, interphase precipitation of V (C, N) in supersaturated ferrite, and precipitations on dislocation after phase transformation are observed, their formation mechanism is discussed.

关 键 词：析出 V N微合金钢 回火硬度法 碳氮化物 铁素体 

分 类 号：TG151.3[金属学及工艺—热处理]