Mo/Nb/Ti/Zr微合金化对Fe-Cr-Al不锈钢第二相析出和显微硬度的影响  

Effect of Mo/Nb/Ti/Zr Minor-alloying on the Second-phase Precipitation and Microhardness in Fe-Cl-Al Stainless Steels

作　　者：王镇华 温冬辉 吕阳[1] 郝家苗 王清[1] 许余 WANG Zhenhua;WEN Donghui;LV Yang;HAO Jiamiao;WANG Qing;XU Yu(Key Laboratory of Materials Modification by Laser,1on and Electron Beams（Ministry of Education）＆ School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;Science and Technology on Reactor Fuel and Materials Laboratory,Nuclear Power Institute of China,)

机构地区：[1]大连理工大学三束材料改性教育部重点实验室&材料科学与工程学院,大连116024 [2]中国核动力研究设计院反应堆燃料及材料重点实验室,成都610213

出　　处：《材料研究学报》2018年第8期575-583,共9页Chinese Journal of Materials Research

基　　金：中国核动力研究设计院反应堆燃料与材料重点实验室基金(ZX20150498);国家重点研发计划(2017YFB0702400);国际热核聚变实验堆计划(2015GB121004);国际科技合作计划(2015DFR60370);广西有色金属及特色材料加工重点实验室开放基金(GXKFJ16-11)~~

摘　　要：研究了Mo/Nb/Ti/Zr微合金化对Fe-Cr-Al不锈钢中第二相的析出和显微硬度的影响。通过团簇式成分设计方法确定了三元基础成分为[Al-(Fe_(12)Cr_2)](Al_(0.5)Cr_(0.5)),进而根据相似元素替代原则添加微量元素设计出系列多元成分合金。使用真空电弧熔炼炉制备合金铸锭并对其进行1200℃/2 h的固溶处理,在800℃进行多道次热轧制成板材,最后进行800℃/24 h时效处理。对系列样品进行XRD结构分析、光学显微镜(OM)和扫描电镜(SEM)显微组织表征以及显微硬度测试。结果表明,添加微量合金化元素的种类和含量影响第二相粒子的析出状态。当合金化元素Mo与Nb的比例(原子百分比)为2:1时析出的第二相粒子在铁素体基体中弥散分布,且粒子尺寸较小,不锈钢的硬度较高为250 HV;在此基础上添加Ti替代Nb使第二相粒子的析出量显著降低而粒子尺寸略有增大,不锈钢的硬度较低为240 HV;添加Zr使析出相的粒子偏聚且粗化,但是其硬度仍然比较高(~246 HV)。The effect of the minor addition of Mo, Nb, Ti, and Zr on the second-phase precipitation and microhardness of Fe-Cr-Al serial alloys were investigated. Ternary composition of [Al-（Fe（12）Cr2）]（Al0.5Cr0.5） was first determined by the cluster formula approach, based on which a minor amount of alloying elements was added to form new alloys. Alloy ingots were prepared by vacuum arc melting, then solid-solution treated at 1200℃ for 2 h, and finally hot-rolled at 800℃ into plates. The plates were further aged at 800℃ for 24 h. The designed alloys were characterized by means of XRD analysis, OM, SEM and microhardness tester. Results showed that both the type and quantity of minor-alloying elements affect the second-phase precipitation. Specifically, when the atomic ratio of Mo：Nb=2：1 the second-phase particles presented as fine precipitates and distributed uniformly in the ferritic matrix, which results in the higher hardness of about 250 HV. While the addition of Ti decreases the volume fraction of precipitated particles in Mo/Nb/Ti-modified alloy obviously, in which the particle size is increased slightly, corresponding to the lower microhardness about 240 HV. The addition of Zr accelerates the segregation of precipitates and coarsens the particle size, but the Mo/Nb/Ti/Zr-modified alloy still showed a relatively-higher microhardness（about 246 HV）.

关 键 词：金属材料 铁素体不锈钢 Fe-Cr-Al系合金 微合金化 第二相析出 

分 类 号：TG142[一般工业技术—材料科学与工程]