SiC泡沫陶瓷/球墨铸铁双连续相复合材料的气固两相流冲蚀性能

Erosion Performance for Co-continuous Phase Composite of SiC Foam Ceramic/Ductile Iron

将SiC泡沫陶瓷氧化后用挤压铸造法制备了SiC泡沫陶瓷/球墨铸铁(DI)双连续相复合材料(SiCfoam/DI)。使用气固两相流冲蚀磨损试验机对比研究了冲蚀时间(t)、粒子速度(ν)和冲蚀角度(α)对SiC颗粒/球墨铸铁复合材料(SiCp/DI)、SiCfoam/DI复合材料和DI冲蚀性能的影响,并分析了冲蚀机理。结果表明:随着冲蚀时间的增加三种材料的冲蚀速率逐渐减小并趋于稳定;随着粒子冲击速度的提高DI的冲蚀速率逐渐增加,冲蚀速率与ν2.95成正比;在冲击速度小于87.5 m/s时SiCp/DI和SiCfoam/DI复合材料的冲蚀速率相近,冲击速度大于87.5 m/s时SiCp/DI复合材料的冲蚀速率明显地比SiCfoam/DI复合材料的高。随着冲蚀角度的增大DI呈现出脆性材料的冲蚀特征,SiCp/DI和SiCfoam/DI表现出典型的塑性材料的冲蚀特征,最大冲蚀速率对应的冲蚀角为45°。低角度时DI的冲蚀机理为微切削,高角度时为冲蚀坑和微裂纹。用高速粒子冲击时,由于SiC泡沫陶瓷的整体增强作用和阴影保护效应,SiCfoam/DI比SiCP/DI和DI具有更高的抗冲蚀磨损性能。

Co-continuous phase composite of SiC foam ceramic/ductile iron(DI)(SiCfoam/DI)was prepared by extrusion casting with the oxidized SiC foam ceramic as reinforcer,while the bare DI and composite of SiCparticles/ID were taken as comparison.The gas-solid two-phase flow induced erosion behavior of the three materials was assessed via a home-made gas-solid two-phase flow erosion tester,so that to reveal the effect of the erosion time(t),particle velocity(ν)and erosion angle(α),as well as the relevant erosion mechanisms.The results show that with the increasing erosion time,the erosion rate of the three materials decreased gradually and then down to a stable level.With the increase of particle impact velocity the erosion rate of DI increased gradually,and the erosion rate is proportional toν2.95.While composites of SiCParticles/DI and SiCfoam/DI had similar erosion rates when the impact velocity was less than 87.5 m/s.When the impact velocity was greater than 87.5 m/s,the erosion rate of SiCParticles/DI was significantly higher than that of SiCfoam/DI.With the increase of erosion angle,DI exhibited erosion characteristics of brittle material,but SiCParticles/DI and SiCfoam/DI composites exhibited typical erosion characteristics of plastic material.The maximum erosion rate corresponded to the erosion angle 45°.The erosion mechanism of DI was micro-cutting at low angle,while erosion pitting and micro-cracking at high angle.For high-speed particle impact,SiCfoam/DI composite had better erosion-and wear-resistance than that of SiCParticles/DI composite and DI due to the overall reinforcement and shadow protection of SiC foam ceramics.