TiC含量对TiCp/M2高速钢复合材料性能的影响

EFFECTS OF TIC CONTENT ON SINTERED PROPERTIES OF TiCp/M2 HIGH SPEED STEEL COMPOSITES

采用高能球磨法制备了TiCp/M2高速钢复合粉末,并利用放电等离子烧结(SPS)技术制备出不同TiC含量的颗粒增强M2粉末冶金高速钢复合材料(TiCp/M2)。测试了粉末粒度分布,观察了粉末形貌及其烧结试样的显微组织,检测了烧结试样的密度、硬度、抗弯强度及摩擦磨损性能,并探讨了复合材料的磨损机理。结果表明:球磨20h后,粉末形态由近似椭球形转变为不规则形状;放电等离子烧结后复合材料的显微组织均匀细小,晶粒平均尺寸小于2μm,M6C型碳化物平均尺寸小于1μm;致密度、抗弯强度随TiC含量的提高而有所降低,硬度在TiC含量为10%时达到最大值59HRC;TiCp/M2试样的磨损量随着TiC含量的增加呈现先下降后上升的趋势,当TiC含量为10%时复合材料具有最佳的耐磨性能,其磨损量约为基体材料的1/3。

TiCp/M2 high speed steel composite powders were prepared by high energy ball milling, and then the composite powders with different TiC content were sintered by spark plasma sintering （SPS）. The high energy ball milling process and SPS sintering microstructure of TiCp/M2 high speed steel composite powders were studied according to the observation of grain size and morphology of the powders and sintered specimen. The physical/mechanical properties had been investigated by measuring the density, hardness, transverse rapture strength and wear resistance, and analyzing the wear mechanism of the composites. Study results showed that the morphology of the powders became irregular shape after 20 h of milling, and the fine microstructure with average size of M6C carbides lower than 1 μm and grain size lower than 2 μm were obtained after sintering. The relative density and transverse rapture strength of the composites decreased with the increase of TiC content, and the maximum hardness of 59 HRC was obtained while the TiC content was 10%. The wear mass of TiCp/M2 composites first fell down and then went up and reached its optimum while the content of TiC was 10%, which wear mass is about 1/3 of M2 high speed steel.