微合金元素对过共析钢轨用钢渗碳体及位错的影响研究

Effect of Microalloying Elements on Cementite and Dislocation of Steel Used In Eutectoid Rail

本文以过共析钢轨用钢为研究对象,选用1℃/s冷速。80%变形量进行双道次热模拟实验,利用SEM、TEM、XRD等表征手段,分析了不同微合金元素对钢中渗碳体特征以及位错组态、位错密度的影响机理。研究结果表明:渗碳体片层厚度随着珠光体片层细化而减小,并且单位体积内渗碳体含量随着片层厚度的减小而增加;加入稀土Ce元素后,渗碳体有局部明显球化现象,以颗粒状弥散分布在铁素体基体中,起到弥散强化的作用。通过对位错组态以及密度分析得知,Ce-Cu复合添加具有显著的位错强化作用。

The influence mechanism of different microalloying elements on cementite characteristics and dislocation configuration,dislocation density was analyzed by means of SEM,TEM,XRD and other characterization methods in the hot compression experiment of 1 Tl/s cooling rate and 80%deformation of eutectoid rail steel.The results show that the thickness of cementite lamella decreases with the thinning of pearlite lamella,and the cementite content per unit volume increases with the decrease of lamella thickness.The spheroidization of local cementite is most obvious after the addition of rare earth Ce element,and the spheroidization of local cementite is distributed in the ferrite matrix in granular form,which plays a role of dispersion strengthening.Through the analysis of dislocation configuration and density,ce-Cu composite addition has the obvious dislocation strengthening effect.