富Ce混合稀土对铝基混杂复合材料耐磨性能的影响

用挤压铸造法制备Al2O3短纤维石墨颗粒混杂增强ZL109复合材料,并研究富Ce混合稀土对该混杂复合材料耐磨性能的影响。结果表明:适量稀土元素可在一定程度上改善该混杂复合材料的耐磨性能,特别在低载荷下,其作用更为显著;稀土对复合材料磨损机制的影响与载荷有关,在较低的载荷下,犁沟磨损是复合材料的主要磨损机制,并存在轻微的剥层破坏;但在较大载荷下,稀土元素加入后,特别是稀土含量高于0.6%后,复合材料的磨损机制由犁沟磨损转变为严重的剥落磨损,复合材料耐磨性反而降低,这可能与稀土含量高时富含稀土的针状相析出有关。

Effect of Ce riched rare earth on wear resistance of aluminum-based hybrid composites

The ZL109 aluminum-alloy-based hybrid composites reinforced with 8% alumina short fibre and 10% graphite particle(volume fraction) were fabricated by squeeze-casting process.The effect of rare earth enriched with Ce on wear resistance of the hybrid composites was investigated.The results show that the addition of RE elements can improve the wear resistance of the hybrid composites and there exists better effect at low load specially.The optimum range of RE content is 0.3%0.6%(mass fraction).The effects of RE on wear mechanisms of the hybrid composites relate closely with the applied load.The ploughing wear is the dominant wear mechanisms of the hybrid composites at low load and there exists slight delamination.However,the dominant wear mechanisms shift to severe delamination when the RE content exceeds 0.6% at high load,and the wear resistance of the hybrid composites decrease,which relates to the precipitation of needle-shaped phase enriched RE elements during heat-treating of the composites with high RE content.