稀土La对NbC在700℃等温析出行为的影响  

Effect of rare earth La on isothermal precipitation behavior of NbC at 700 ℃

作　　者：雷梓华 方琪[1,2,3] 金自力 孙伟[1,2,3] 熊东东 Lei Zihua;Fang Qi;Jin Zili;Sun Wei;Xiong Dongdong(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,China;Key Laboratory of New Metal Materials of Inner Mongolia Autonomous Region,Baotou Inner Mongolia 014010,China;Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-Metal Resources,Baotou Inner Mongolia 014010,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 [2]内蒙古自治区新金属材料重点实验室,内蒙古包头014010 [3]白云鄂博共伴生矿资源高效综合利用省部共建协同创新中心,内蒙古包头014010

出　　处：《金属热处理》2022年第10期46-52,共7页Heat Treatment of Metals

基　　金：内蒙古自治区自然科学基金(2019MS05051);内蒙古自治区科技重大专项(zdzx2018032)。

摘　　要：对不同稀土La含量(0、0.0006%和0.0048%)的Nb微合金化试验钢进行1250℃固溶+700℃盐浴等温处理,研究了在铁素体区等温不同时间下,稀土对NbC析出行为的影响。结果表明,在钢中加入稀土La能够促进Nb在1250℃时的固溶,未溶第二相数量减少;700℃等温时,在析出开始阶段,稀土的促进作用相对较弱,随着等温时间的延长,稀土的促进作用逐渐显著。稀土La使NbC析出动力学曲线左移,加入0.0048%La使NbC析出开始时间由199 s缩短至125 s,结束时间由35 183 s缩短至29 128 s;等温时间为10^(4.25)s时,与不加稀土时相比,添加稀土后试验钢在铁素体区700℃等温10^(4.25)s后析出的NbC第二相尺寸小,不加稀土时NbC尺寸主要分布在10~20 nm,占42.8%,而添加0.0006%La和0.0048%La时,NbC尺寸主要分布在1~10 nm之间,分别占53.6%和64.3%,表明稀土La的添加使NbC尺寸得到了明显的细化。By solution treated at 1250 ℃ and salt bath isothermally treated at 700 ℃, the effect of rare earth on isothermal precipitation behavior of NbC in Nb-microalloyed steels with adding La of 0, 0.0006% and 0.0048%, respectively, in the ferrite region for different time was studied. The results show that the addition of rare earth La into the steel can promote the dissolving of niobium at 1250 ℃ and reduce the number of undissolved second phases. When isothermally treated at 700 ℃, the promotion effect of rare earth is relatively weak at the beginning of precipitation, and gradually becomes significant with the increase of isothermal time. Rare earth La makes the NbC precipitation kinetic curve shift to the left. The addition of 0.0048% rare earth reduces the precipitation start time from 199 s to 125 s, and the end time from 35 183 s to 29 128 s. When isothermally treated at 700 ℃ for 10^(4.25)s, the size of the second phase NbC precipitated in the ferrite area of the steel containing rare earth is smaller compared with that in the steel without rare earth. The size of the precipitated NbC in the steel without La is mainly in the range of 10-20 nm, accounting for 42.8%, while the size of the precipitated NbC in the steel containing 0.0006%La and 0.0048%La is mainly in the range of 1-10 nm, accounting for 53.6% and 64.3%, respectively, which indicates that the addition of rare earth La can refine the size of NbC significantly.

关 键 词：LA 微合金钢 NBC 析出动力学 

分 类 号：TG142.1[一般工业技术—材料科学与工程]