Y_2O_3含量对40Cr钢激光表面合金化组织与性能的影响

Effect of Y_2O_3 content on microstructure and properties of laser alloying layer on 40Cr steel

为了改善金属拉拔卷筒的耐磨性能,采用CO2激光对40Cr钢拉拔卷筒表面进行激光合金化处理,利用OM、XRD、显微硬度计、SEM、磨损试验机研究了Y2O3对合金化层的组织性能的影响。结果表明:Y2O3添加量在0～2.5%变化时,随着Y2O3含量的增加,合金化层组织逐渐变细,Y2O3含量在1.0%时,合金化层组织最细,Y2O3的含量大于1.0%时,合金化层的组织反而变的粗大。未添加Y2O3时,合金化层除了基体相α-Fe外,同时还包括MoC、Cr3Mo、Cr7C3和Fe2MoC等相。添加Y2O3后,还生成了少量的FeCrMo相。Y2O3还可以抑制Mo、Cr等原子由晶内向晶界扩散。Y2O3添加量为1.0%时,合金化层具有最高的硬度和耐磨性,当Y2O3含量大于1.0%时,合金化层的硬度和耐磨性随着Y2O3含量的增加反而降低。

Surface of the metal wire drawing roller was alloyed with Mo and Y2O3 by CO2 laser in order to improve its wear resistance.The effects of Y2O3 content on microstructure and properties of the alloying layer were investigated by means of OM,XRD,SEM,hardness and wear tests.The experimental results indicate that as the content of Y2O3 increases from 0 to 2.5%,the grain size in the alloying layer is gradually refined.When the content of Y2O3 is 1.0%,the finest grain size is obtained.However,the grain size in alloying layer becomes coarser with the further increase of Y2O3 content.The microstructure consists of main phase α-Fe and phases of MoC,Cr3Mo,Cr7C3 and Fe2MoC for the alloying layer without addition of Y2O3.When adding Y2O3 into the alloying layer,a new phase FeCrMo appears in the alloying layer.Y2O3 addition in the layer can hinder the diffusion of Mo and Cr atom from grain interior to grain boundary.The alloying layer exhibits the highest hardness and the best wear resistance when the content of Y2O3 is 1.0%,however,the hardness and wear resistance of the alloying layer decreases when the content of Y2O3 is more than 1.0%.