Nb-Mo-V微合金钢中回火硬度峰值时碳化物的研究  

STUDY ON PRECIPITATION OF THE CARBIDE AT PEAK HARDNESS DURING TEMPERING IN Nb-Mo-V-BEARING MICRO-ALLOYED STEEL

作　　者：王泽民[1,2] 宋辉[1] 王晓姣[1] 刘文庆[1] 

机构地区：[1]上海大学微结构重点实验室,上海200444 [2]上海应用技术学院材料科学与工程学院,上海201418

出　　处：《上海金属》2013年第5期1-4,共4页Shanghai Metals

基　　金：国家自然基金重点(50931003)资助项目

摘　　要：Nb-Mo-V微合金钢固溶后在450~650℃温度下回火不同时间,利用透射电镜(TEM)和三维原子探针(3DAP)对不同温度回火硬度峰值样品的显微组织及碳化物进行分析。结果表明:回火温度越高,样品硬度达到峰值所需的回火时间越短;析出强化效果最佳时合金碳化物的等效半径约1.0 nm,数量密度约2.0×10^(24)m^(-3);450℃样品中碳化物是以Nb_4C_3为核心,在渗碳体中原位形核而成,合金元素与碳原子配比接近4:3;500~650℃样品中碳化物的合金元素和碳原子形成团簇、偏聚分布在基体中,并未形成独立晶体结构和稳定元素化学计量配比。Three dimensional atom probe （3DAP） and transmission electron microscopy （TEM） were applied to characterize the microstructure and carbides of Nb-Mo-V micro-alloyed steel sample at peak hardness by tempering at 450 -650 ℃ after solution treatment. The results showed that the tempering time for the peak hardness needed became shorter with the tempering temperature increased. The size and number density of the carbides were about 1. 1 nm and 2.0 x 1024 m-3 respectively, corresponding to the strongest precipitation strength. Nb4C3 in-situ nucleated inside of the cementite as the core of the carbides in peak hardness samples tempered at 450 ℃, the atomic ratio of alloy elements to carbon of the carbides closed to 4： 3, alloying elements and carbon formed clusters and congregating in the matrix, having not formed independent crystal structure and stoiehiometric ratio of elements in peak hardness samples tempered at 500 -650 ℃.

关 键 词：微合金钢 三维原子探针 合金碳化物 硬度峰值 回火 

分 类 号：TG142.45[一般工业技术—材料科学与工程]