稀土铈对内生TiC型超级耐磨钢组织性能的影响

 作为耐磨钢研究的新领域,引入高体积分数TiC粒子的超级耐磨钢,虽然能够提升钢的耐磨性,但会降低材料的韧塑性。为了提升超级耐磨钢的综合性能,研究稀土铈对超级耐磨钢组织性能的影响,采用真空感应炉冶炼出不同铈质量分数的试验钢,通过扫描电镜(SEM)、电子背散射衍射(EBSD)、电子探针(EPMA)、硬度测试、低温冲击性能测试、磨损性能测试等手段,研究了铈对试验钢TiC粒子析出行为、组织、力学性能以及耐磨性能的影响。结果表明,热处理后试验钢的组织为回火马氏体。铈可以将高钛耐磨钢中TiC、TiN粒子改性为Ce₂O₂S-TiC、Ce₂O₂S-TiN、CeP-TiC和xCeP·yCe₂O₃-TiC稀土复合粒子。随着铈质量分数的增加,试验钢的强度和硬度变化不大,低温韧性和耐磨性先提高后下降,在铈质量分数为0.002 5%时,其综合性能最佳,相对耐磨性为未添加铈试验钢的1.27倍。

Effect of rare earth Ce on microstructure and properties of super wear-resistant steel with in-situ TiC particles

As a new research field in wear-resistant steel,the addition of high volume percent of TiC particles could improve the wear resistance of super wear-resistant steel,but it would reduce the toughness and plasticity of the material. In order to improve the comprehensive mechanical properties of super wear-resistant steel,the effect of rare earth Ce on the microstructure and properties of super wear-resistant steel was investigated. A vacuum induction melting furnace was used to produce the experimental steels with different mass percent of Ce. Using scanning electron microscopy (SEM),electron back scattered diffraction (EBSD),emission electron probe microscopic analyzer (EPMA),hardness testing,low-temperature impact testing and wear resistance testing to study the influence of rare earth Ce on the precipitation behavior of TiC particles,microstructure,mechanical properties and wear resistance of experimental steels. The results indicated that the microstructure of the experimental steel was tempered martensite after heat treatment,some TiC and TiN particles in experimental steel were modified into micron sized Ce₂O₂S-TiC,Ce₂O₂S-TiN,CeP-TiC and xCeP·yCe₂O₃-TiC composite inclusions after adding Ce. With the increasing of the mass percent of Ce,the low-temperature impact toughness and wear resistance first increase and then decrease,but the strength and hardness have little change. When the mass percent of Ce was 0.002 5%,the optimum comprehensive properties can be obtained,and the relative wear resistance was 1.27 times of the experimental steel without Ce addition.