【摘要】 为了提高在严峻工况条件下工作的机械零件的耐磨性,采用等离子熔覆技术,在20 g钢表面制备了一系列Fe-15Cr-xV-0.8C堆焊合金.借助光学显微镜、扫描电镜和x-射线衍射等分析手段研究了合金组织和碳化物形貌.结果表明:堆焊合金显微组织由马氏体、铁素体、少量奥氏体、M7C3和VC组成.合金中加入一定数量的V,可诱发基体的马氏体转变,改善合金的耐磨性.随着V的质量分数的增加,VC的数量增加,堆焊合金晶粒显著细化.此外,考察了V的质量分数对堆焊合金硬度及耐磨性的影响.耐磨粒磨损实验结果表明:堆焊合金耐磨性优良,当合金中存在较多数量的硬质相且硬质相分布均匀、晶粒大小适中时,能有效阻止磨粒的显微切削运动,显著提高材料的耐磨性.更多还原

【Abstract】 In order to improve the wear resistance of machine parts subjected to severe operating conditions,a series of Fe-15Cr-xV-0.8C hardfacing alloys were prepared on the surface of 20 g steel with with a plasma cladding technology.The microstructures of the alloys and the morphologies of carbides were investigated by means of optical microscopy(OP),scanning electron microscopy(SEM) and X-ray diffractometer(XRD).The results show that the microstructure of the hardfacing alloys consist of martensite,ferrite,small amount of austenite as well as M7C3 and VC phases.The addition of V element into the hardfacing alloys can induce the martensitic transformation of the matrix and improve the wear resistance of the alloys.With increasing the mass fraction of V element,the amount of VC phase increases,and the grains inside the hardfacing alloys get remarkably refined.In addition,the effect of V content on the hardness and wear resistance of the hardfacing alloys was examined.The results of abrasive wear resistance experiments indicate that the hardfacing alloys have excellent wear resistance.When large amount of hardening phases uniformly distribute and the grain size is moderate in the hardfacing alloys,the micro-cutting movement of abrasive particles can be effectively prevented,and the wear resistance of the alloys can be enhanced obviously.更多还原