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

• Published in: Transactions of Nonferrous Metals Society of China Vol. 20; no. B07; pp. 471 - 475
• Main Author: 张美娟 曹占义 杨晓红 刘勇兵
• Format: Journal Article
• Language: English
• Published: 01.07.2010
• Subjects: Al2O3; AZ91D镁合金; 复合材料性能; 微观结构; 石墨颗粒; 磨损性能; 磨损机制; 镁基复合材料
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(10)60521-3

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.