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为了研究颗粒增强金属基复合材料的高周疲劳损伤机制,对压力浸渗法制备的TiB2P/2024Al复合材料进行了轴向疲劳实验,采用扫描电子显微镜观察了疲劳断口.结果表明:裂纹多萌生于材料的内部缺陷处;损伤模式主要为基体微孔聚集型损伤和颗粒-基体之间界面脱黏,颗粒开裂现象极少;裂纹的主要扩展区呈现韧窝和细小疲劳辉纹共存的特征.较小的增强颗粒降低了材料内部局部应力集中,弥散化了损伤的萌生位置的空间分布,增加了微裂纹的偏折和分岔的可能性,充分发挥了基体的塑性,进而提高了材料的疲劳性能.
In order to study the high-cycle fatigue damage mechanism of the particle reinforced metal matrix composites, the axial fatigue test of TiB2P / 2024Al composites prepared by pressure infiltration method was carried out and the fatigue fracture was observed by scanning electron microscopy.The results show that: The main damage modes are the accumulation of micro-pores in the matrix and the debonding of the interface between the particles and the matrix, and the cracking of the particles is very rare. The main extension of the crack shows the coexistence of the dimples and the micro-fatigue fusions. The small reinforcing particles reduce the local stress concentration in the material and disperse the spatial distribution of damage initiation sites, increase the possibility of micro-crack deflection and bifurcation, give full play to the plasticity of the matrix and further improve the material fatigue performance.