共晶Fe-Cr-B-C合金的快冷组织与性能

Microstructure and Properties of Eutectic Fe-Cr-B-C Alloy Prepared by Rapid Cooling

通过中频感应炉熔炼、快冷,制备出共晶Fe-Cr-B-C合金。采用OM、SEM(附带EDS)、XRD观察了共晶Fe-Cr-B-C合金的组织,并检测其硬度和冲击韧性。结果表明:铸态Fe-Cr-B-C合金的宏观硬度为HRC68,冲击韧性达到13.6 J/cm^2;组织由马氏体+残余奥氏体基体和沿晶界连续网状分布的(Fe,Cr)_2(B,C)+(Fe,Cr)_(23)(B,C)_6硬质相组成。经960℃×2 h退火后,合金的宏观硬度降低为HRC46,冲击韧性减少到3.4 J/cm^2;基体组织转变为铁素体和粒状渗碳体,硬质相(Fe,Cr)_2(B,C)和(Fe,Cr)_(23)(B,C)_6少量溶解,局部区域出现断网,生成新相(Fe,Cr)_3(B,C)。

The eutectic Fe-Cr-B-C alloy was prepared by the medium-frequency induction furnace and rapid cooling forming. The microstructures of the eutectic Fe-Cr-B-C alloy were studied by means of optical microscope （OM）, scanning electron microscope （SEM） with energy dispersive spectrometer analysis （EDS）, X-ray diffraction（XRD）. In addition, the hardness and impact toughness of alloy were measured. The results show that the macrohardness of as-cast Fe-Cr-B-C alloy is HRC 68 and the impact toughness is 13.6 J/cm^2, the microstructure of the alloy consists ofmartensite, retained austenite matrix and （Fe,Cr）2（B,C） and （Fe,Cr）23（B,C）6 hard phase, hard phase form continuous reticulation and distribute along the grain boundary. After 960 ℃ insulation for 2 hours annealing the macrohardness of the alloy was reduced to HRC 46, the impact toughness was reduced to 3.4 J/cm^2, the matrix structure was transformed into ferrite and granular cementite, （Fe, Cr）2（B,C） and （Fe,Cr）23（B,C）6 hard phase dissolved in a small amount of local reticular structure, the new phase （Fe,Cr）3（B, C） appeared.