摘要
采用预制体和挤压铸造结合法制备以AZ91D-Cex镁合金为基体,Al2O3短纤维和石墨颗粒混杂增强复合材料,分析不同稀土含量下复合材料的显微组织并测量其硬度,同时考察载荷对复合材料磨损性能的影响.结果表明:复合材料中石墨和Al2O3短纤维分布均匀,与基体结合紧密,稀土Ce沿石墨和Al2O3短纤维的边界富集,其结构为Al3Ce相;复合材料的硬度随稀土含量增加而提高,其中含1.0%Ce合金复合材料的硬度最高;复合材料的磨损率随着稀土含量增加而降低,在20N时3种复合材料的磨损率差别不大,在180N时,含1.0%Ce合金的耐磨性最佳.这是由于石墨作为润滑相对摩擦表面起到润滑作用,同时稀土强化相Al3Ce的热稳定性较好,在高载荷时具有较好承载能力,延迟了磨损表面由轻微磨损向剥层磨损的转变.在低载荷时复合材料的磨损机制为磨粒磨损和氧化磨损,在高载荷时为剥层磨损.
Graphite and Al2O3 short fibers reinforced AZ91 D-Cex composites were fabricated by squeeze-infiltration technique. Microstructure, hardness and wear behavior of the composites were investigated under the condition of constant volume of graphite and Al2O3 short fibers, especially the effect of rare earth Ce on the properties was studied. The reinforcement phase dispersed uniformly and no agglomerate and casting defect were observed. Ce was enriched around the boundaries of graphite and Al2O3 short fibers, and it formed Al3Ce phase. The hardness of the composites increased with increasing of Ce content, the composite of 1.0% Ce had the highest hardness. Three composites had nearly the same wear rate at 20 N, but the composite of 1.0% Ce had better wear resistance at 180 N. Graphite formed a localized lubricant film on the worn surface, and Al3Ce phase had better chemistry stabilization, so the composites improved the strength of the composite. When increasing load, the transition from mild wear to severe wear was delayed. At low load the wear mechanism was abrasion and oxidation wear, at high load the wear mechanism changed to delamination wear for all the composites.
出处
《摩擦学学报》
EI
CAS
CSCD
北大核心
2008年第3期230-234,共5页
Tribology
基金
吉林省科技厅应用基础研究项目资助(20010563)
国家"863计划"引导项目资助(2002AA001022)
吉林省科技发展计划资助项目(20030503-1)
吉林大学"九八五工程"科技创新平台资助项目
关键词
镁基复合材料
稀土
石墨
磨损性能
magnesium matrix composite, rare earth, graphite, wear behavior
