石墨颗粒含量对(Gr_p+Al_2O_3-SiO_(2f))/ZL109混杂复合材料摩擦磨损性能的影响

Effect of Graphite Content on Friction and Wear Properties of Aluminosilicate Short Fiber and Graphite Particle Reinforced Al-12Si Hybrid Composites

利用挤压铸造法制备了硅酸铝短纤维(Al2O3-SiO2f)和石墨颗粒(Grp)混杂增强ZL109铝合金复合材料,并研究了石墨颗粒含量对该混杂复合材料摩擦磨损性能的影响规律.结果表明:石墨颗粒在混杂复合材料中可以起到明显的自润滑作用,特别在干摩擦高速磨损条件下其作用更为明显.当石墨颗粒含量超过5～8%时,混杂复合材料的摩擦系数保持在一个稳定的低值.无论在干摩擦还是在油润滑磨损条件下,单一硅酸铝短纤维增强复合材料的耐磨性较基体大幅度提高,而经石墨颗粒混杂后复合材料的耐磨性进一步提高,其含量在5～8%之间时其相对耐磨性取得最高值,而增强体更有利于复合材料干摩擦磨损性能的提高.

Aluminosilicate short fiber（Al2O3-SiO2f） and graphite particle reinforced Al-12Si aluminum alloy hybrid composites were fabricated by squeeze casting. The effect of graphite content on friction and wear properties of the hybrid composites was investigated in this study by MM-200 wear equipment. The results show that graphite particle was of obvious self-lubricant effect in the hybrid composites, especially at high sliding speed under the condition of dry sliding friction. When graphite content was less than the range of 5 - 8vol. %, friction coefficient of the hybrid composites contained fixed 20vol. % Al2O3-SiO2f decreased quickly with increasing graphite content. However,friction coefficient of the hybrid composites kept a low constant value when graphite content was beyond the range. Whether dry or oil-lubricated sliding friction, wear resistance of the composites reinforced separately 20vol. % Al2O3-SiO2f improved markedly compared to monolithic Al-12Si alloy. Moreover, the addition of graphite particle in the composites reinforced with 20vol. % Al2O3-SiO2f improved wear resistance further and there existed optimum graphite content range between 5 -8vol. % resulting in the best wear property. Compared to oillubricated condition, reinforcements contributed to improvement of wear resistance of the hybrid composites much more under dry sliding friction.