ZnAl2O4涂覆 Al18B4O33(w)增强6061Al 复合材料界面结构与拉伸性能

Interfacial microstructure and tensile properties of 6061Al matrix composite reinforced with ZnAl2O4-coated Al18B4O33 whiskers

  • 摘要: 使用溶胶-凝胶法在硼酸铝晶须表面制备ZnAl2O4涂层,采用挤压铸造法制备了ZnAl2O4涂覆的硼酸铝晶须增强6061Al 复合材料。研究了ZnAl2O4涂覆对复合材料界面润湿性、室温拉伸性能以及高温热暴露后界面热稳定性的影响。试验结果表明: 纳米ZnAl2O4涂覆能够明显提高复合材料的界面润湿性 , 从而提高复合材料的室温拉伸性能; 均匀的ZnAl2O4涂覆能有效地阻碍界面反应,使复合材料具有良好的热稳定性能。研究了涂覆对复合材料在铸态及高温热暴露后拉伸断裂行为的影响。未涂覆硼酸铝晶须增强的铝基复合材料在拉伸变形过程中晶须以折断为主,ZnAl2O4涂覆硼酸铝晶须增强的铝基复合材料在拉伸变形过程中晶须以拔出为主。

     

    Abstract: The ZnAl2O4 coating was fabricated on the surface of the aluminum borate whiskers by a sol-gel method,and the 6061Al matrix composite reinforced with ZnAl2O4-coated aluminum borate whiskers was fabricated by squeeze casting. The effects of the ZnAl2O4 coating on interface wet tability,tensile properties at room temperature and interfacial thermal stability after thermal exposure of the composite were investigated. The experimental results show that the nano- ZnAl2O4 coating can remarkably improve the interface wet tability of the composite,and thus improve the tensile properties at room temperature of the composite. The uniform ZnAl2O4 coating can effectively hinder the interfacial reaction and make the composite keep good thermal stability. At the same time,the effect of the coating on the tensile fracture behavior of the composite in as-cast and after thermal exposure was investigated. The fracture of whiskers is in the majority during the tensile deformation of the aluminum matrix composite reinforced with uncoated aluminum borate whiskers,however,the pull-out of whiskers is in the majority during the tensile deformation of the aluminum matrix composite reinforced with ZnAl2O4-coated aluminum borate whiskers.

     

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