碳化硅颗粒表面吸附质对铝基复合材料制备及力学性能的影响

选用粒度为60～80μm的国产磨料级碳化硅颗粒作为增强体、以无压浸渗法制备高体份SiC_p/Al复合材料,采用超声清洗工艺对比研究颗粒表面吸附质对颗粒浸渗性以及复合材料力学性能的影响。结果表明:国产磨料级碳化硅颗粒表面普遍存在少量吸附质(<0.5%),吸附质以粒度更小(<5μm)的碳化硅颗粒为主,个别情况含有少量的游离碳。颗粒表面吸附质的存在严重影响了颗粒表面与熔融铝液的润湿性,并且会大幅度降低复合材料的密度和力学性能。超声清洗工艺可以有效去除碳化硅颗粒表面的吸附质,去除吸附质之后颗粒的浸渗成功率从25%提升至100%,复合材料的抗弯强度从320MPa提升至390MPa,弹性模量从203GPa提升至232GPa。

Effect of the surface adsorbate of SiC particles on fabrication and mechanical property of aluminum matrix composite

SiC p/Al composites were prepared by pressureless infiltration using domestic abrasive grade SiC particles with average diameters in the range of 60-80μm.Ultrasonic cleaning method was used to investigate the effect of the surface adsorbate of SiC particles on the infiltration process and mechanical property of the SiC p/Al composite.The results show that all types of the studied SiC particles are adhered by low mass fractions of the adsorbate(<0.5%),comprising mainly fine SiC particles(<5μm)and,in certain cases,low fraction of carbon.That surface adsorbate has a negative effect on the wettability between SiC particles and molten alloy,resulting in the reduced density and mechanical property of the infiltrated SiC p/Al composite.Ultrasonic cleaning process can effectively wipe off the adsorbate,and,by using the cleaned SiC particles,the success rate of the infiltration can be raised from 25%to 100%.Correspondingly,the flexure strength and elasticity modulus of the composites are improved from 320MPa to 390MPa and from 203GPa to 232GPa,respectively.