低碳微量铌钢过冷奥氏体形变过程中的碳氮化物析出  

Carbonitride precipitates during deformation of undercooled austenite in Nb-microalloyed steel

作　　者：陈国安[1] 杨王玥[1] 郭守真[1] 孙祖庆[2] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]新金属材料国家重点实验室,北京100083

出　　处：《北京科技大学学报》2005年第3期302-306,共5页Journal of University of Science and Technology Beijing

基　　金：国家"863"资助项目(No.2001AA332020)国家自然科学基金(No.50471092)中信铌钢资助项目

摘　　要：利用透射电镜研究了低碳微量铌钢过冷奥氏体形变过程中的碳氮化物析出,运用Gla- dman晶粒粗化机制讨论了析出相颗粒的平均直径、体积分数和铁素体晶粒尺寸的关系.实验结果表明:实验用钢中的微量Nb在1200℃时完全固溶,并在760℃变形前的冷却过程中无Nb(CN)析出.在形变过程中Nb(CN)的析出同样需要孕育期,但与等温过程相比大大提前.当变形量积累到一定值(本实验条件下ε=0.69)时,大量动态析出的Nb(CN)颗粒弥散分布在晶界以及位错线上.Nb(CN)析出随着应变量的增加而增加,但颗粒长大不明显,计算得到的铁素体晶粒平均截径与实际测得的铁素体晶粒吻合得较好.By using TEM the strain-induced precipitation of Nb(CN) during deformation of under cooled austenite was investigated in Nb-microalloyed steel. The results showed that at 1200°C all of Nb were dissolved and there were no Nb(CN) precipitates formed during cooling until down to 760°C. During deformation-enhanced ferrite transformation the Nb(CN) of dynamic precipitation required an incubation period, but compared with isothermal transformation it reduced significantly. Only when the strain increased to 0.69, Nb(CN) began to precipitate on dislocation nodes and grain boundaries. The volume fraction of Nb(CN) precipitates increased with the increase of strain but their coarsening was not significant. It is shown that the measured grain size is in good agreement with the calculated value.

关 键 词：Nb(CN)析出 孕育期 体积分数 析出长大 

分 类 号：TG111.2[金属学及工艺—物理冶金] TG142.31[金属学及工艺—金属学]