Microstructures and wear properties of graphite and Al₂O₃ reinforced AZ91D-Ce_x composites

来源期刊：中国有色金属学报(英文版)2010年增刊第2期

论文作者：张美娟 曹占义 杨晓红 刘勇兵

文章页码：471 - 475

Key words：magnesium matrix composite; graphite; Ce; wear property

Abstract: The magnesium matrix composites reinforced by graphite particles and Al₂O₃ short fibers were fabricated by squeeze-infiltration technique. The additions dispersed uniformly and no agglomeration and casting defect were observed. The microstructures and wear properties of the composites with different Ce contents of 0, 0.4%, 0.8% and 1.0%, respectively, were investigated. Especially, the effect of Ce on the properties was discussed. The results reveal that Ce enriches around the boundaries of graphite particles and forms Al₃Ce phase with Al. The addition of Ce refines the microstructures of the composites. With the increase of Ce content, the grain size becomes smaller and the wear resistance of the composite is improved. At low load, the composites have similar worn surface. At high load, the composite with 1.0% Ce has the best wear resistance due to the existence of Al₃Ce phase. The Al₃Ce phase improves the thermal stability of the matrix so the graphite particles can keep intact, which can still work as lubricant. At low load, the wear mechanism is abrasive wear and oxidation wear. At high load, the wear mechanism changes to delamination wear for all the composites.