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采用固体渗碳法对95W-3.4Ni-1.6Fe高比重合金进行了渗碳处理,并在球棒试验机上研究了渗碳处理对钨合金接触疲劳性能的影响。利用SEM、EDS、XRD、表面形貌仪等手段对渗碳钨合金的显微组织和疲劳损伤形貌等进行了表征。结果表明,渗碳处理后钨合金表面由较薄的多孔碳化钨层和被碳化钨包裹的改性钨颗粒层组成。渗碳处理不仅降低了钨合金的接触疲劳性能而且加剧了对偶件钢球的磨损。钨合金的损坏机制为剥落和层状分离,次表层主裂纹易在最大剪切应力处萌生并沿着钨–钨界面扩展。渗碳钨合金的损坏是由碳化钨颗粒的剥落造成,同时剥落后的碳化钨颗粒在接触界面间充当第三体,加剧了渗碳钨合金的表面磨损。
The solid carburizing method was used to carburize 95W-3.4Ni-1.6Fe alloy with high specific gravity. The effect of carburizing treatment on the contact fatigue properties of tungsten alloy was investigated on a bat tester. The microstructure and fatigue damage morphology of carburized tungsten alloy were characterized by SEM, EDS, XRD and surface topography. The results show that the surface of the tungsten alloy after carburizing treatment consists of a thin porous tungsten carbide layer and a modified tungsten particle layer surrounded by tungsten carbide. Carburizing not only reduces the contact fatigue properties of tungsten alloys but also aggravates the wear of the balls of the couple. The failure mechanism of the tungsten alloy is exfoliation and delamination separation. The subsurface primary cracks are easy to initiate at the maximum shear stress and extend along the tungsten-tungsten interface. The failure of the carburized tungsten alloy is caused by the spalling of the tungsten carbide particles, while the stripped tungsten carbide particles act as the third body between the contact interfaces, aggravating the surface wear of the carburized tungsten alloy.