TiC/Fe表面梯度复合材料微区组织及陶瓷层磨损性能
Microstructure of matrix and wear resistance of ceramic layer of TiC/Fe surface gradient composites
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摘要: 采用灰铸铁(HT300)与厚度为0.25 mm的钛板,通过浇注法使得灰铸铁与钛板紧密结合,在真空管式炉中1 138℃保温时间8 h后,等温处理并炉冷.通过观察,在基体表面原位生成了TiC颗粒增强铁基表面梯度复合材料,对梯度复合区进行显微组织观察、显微硬度测量以及磨损性能测试.结果表明,TiC颗粒增强表面梯度复合材料大致分为三层,各层之间最大的区别是:生成的TiC颗粒的大小及形状不相同;从复合层(C区)到珠光体区显微硬度逐渐降低,显微硬度最大的区域出现在致密陶瓷层(C区).因此对TiC颗粒增强表面梯度复合材料致密陶瓷层进行了磨粒磨损试验,表明陶瓷层耐磨性比灰铸铁(HT300)有了很大程度上的提高.Abstract: In this paper,the joining of gray cast iron (HT300) and titanium plate with the thickness of 0.25 mm was performed by the method of pouring. The sample was isothermally kept in vacuum tube furnace at 1 138℃ for 8 h,and cooled in furnace to room temperature. TiC particulates reinforced surface gradient composite was prepared on the iron matrix of cast iron surface by the in-situ technology. Microstructure analysis, microhardness and wear-resistance test were carried out on the recombination region. The experimental results show that the TiC particulates reinforced surface gradient composite is composed of three layers. The difference between the three layers lies in the different sizes and different shapes of TiC particulates. The microhardness decreases gradually from composite layer (C region) to pearlite region. The maximum microhardness appears in the high density ceramic layer (C region). Therefore,wear experiment was further performed to study wear-resistance of the high density ceramic layer of the surface gradient composite. Apparently, the wear-resistance of high density ceramic layer is enhanced greatly in comparison with gray cast iron.