预置法对V-EPC铸渗制备复合材料组织和质量的影响

通过涂覆预制块法和压制预制块法两种预置体的预置方法,利用V-EPC铸渗工艺制备了WC增强铁基表面复合材料,着重研究了两种预置法对复合材料的表面质量和组织的影响。结果表明,压制法制备的复合材料表面质量较涂覆法好,复合层厚度均为3 mm左右,表面较平整,复合位置对铸渗件表面质量影响不大,且随着WC颗粒体积分数的增加,复合材料铸件的铸渗层表面质量呈下降趋势。对显微组织的研究表明,两种方法制备的复合材料过渡层都较平缓,在压制法制备的复合材料靠近复合层处的过渡层组织中没有石墨出现。压制法制备的复合材料复合层中WC的分布较涂覆法均匀,WC颗粒体积分数较高,WC的大小不一,一些WC颗粒产生裂纹、破碎和搭接现象,随着WC颗粒体积分数的增加,WC颗粒将变均匀。

Effect of Presetting Methods on the Quality and Microstructure of Composites Prepared by V-EPC Infiltration

Using two presetting methods of suppressed preform and coated preform,WC particles reinforced iron matrix surface-layer composites were prepared by V-EPC infiltration.The effects of two presetting methods on quality and microstructure of composites were focused in the study.The results indicated that,compared with coated preform method,the surface quality of the composites made with suppressed preform method was more smoothing,the composite layer thickness of which was 3 mm,and the effect of composite locality on surface quality was few.With the increasing of WC particles volume fraction,the surface quality of the composites made with suppressed preform method was decreased.The study of microstructure showed that,the transitional layer of the composites made by two presetting methods was flattish and that of the composites by suppressed preform method didn't consist of graphite in the layer.Compared with coated preform method,the distribution of WC particles was more uniform,WC volume fraction was higher,WC particles' size was mean and few WC particle had crazing,fracture and overlapped appearance in the composites made by suppressed preform method.And with the increasing of WC particles volume fraction,WC particles become more uniform.