摘要
通过高Nb、V或Ti(~0.1%),低Mo(≤0.2%)微合金化设计,在经TMCP工艺后用恒载荷拉伸实验测定了Fe-C-M-Mo(M=Nb、V或Ti)系合金钢的失效温度。用EBSD分析了TMCP后样品中的界面密度,用TEM观测了恒载拉伸实验后样品中的纳米析出相。结果表明:在Fe-C-V/Nb钢中添加约0.2%Mo使其在280 MPa恒载荷拉伸升温过程中的失效温度提高约40℃。小角度界面为MC型析出相形核析出提供了有利位置,加速了MC相的析出,在升温过程中细小弥散的MC相在小角度界面形核析出起到了良好的高温沉淀强化作用,提高了耐火钢的失效温度。含Mo的Ti-Mo钢具有较高的小角度界面密度,导致其中MC型析出相析出较快,因此具有最高的失效温度,Nb-Mo钢次之,V-Mo钢因小角度界面密度最小使其在高温下MC相析出的动力学减缓,因此失效温度最低。
Fe- C- Mo- M steels(where M is Nb, V or Ti, ~0.1%, and Mo ≤0.2%) were produced by thermal mechanical control processing(TMCP), and then their performance was characterized in terms of failure temperature by means of constant load tensile test while heating from ambient temperature up to 800 oC with a heating rate 28oC/min. The boundary misorientation of the steels after TMCP was examined by electron back scattered diffraction(EBSD), and the precipitates of MC type carbides were characterized by transmission electron microscopy(TEM). The results show that the addition of 0.2% Mo in FeC-Nab/V steels increases the failure temperature of steels by 40℃. It is believed that the low-angle grain boundary provided the favorable nucleation site for MC type carbides, which in turn will accelerate the kinetics of precipitation process. The fine and dispersed precipitates of MC type carbides induce significant precipitation strengthening for the steels during the constant load tensile process, thus resulting in higherfailure temperature. Among the tested steels, the failure temperature of Ti-Mo steel is the highest due to its highest low- angle grain boundary density which results in the fast precipitation of MC type carbides.The failure temperature of Nb-Mo steel comes the second and that of the V-Mo steels is the lowest because of its lowest low angle grain boundary density leading to the lowest density of precipitated MC type carbides.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2015年第4期269-276,共8页
Chinese Journal of Materials Research
基金
国家重点基础研究发展计划2010CB630805
国家自然科学基金51201036资助项目~~
关键词
金属材料
智能型耐火钢
失效温度
沉淀强化
小角度界面密度
纳米级碳化物
metallic material,intelligent fire resistant steel,failure temperature,precipitation strengthening,low-angle grain boundary dens
