粉末冶金热挤法制备无钯镀镍碳纤维增强镁基复合材料及组织观察

利用粉末冶金热挤压技术制备短碳纤维增强镁合金复合材料。为了改善碳纤维与基体的润湿性,对碳纤维进行表面无钯化学镀镍处理。通过扫描电子显微镜(SEM)观察碳纤维化镀层以及碳纤维镁基复合体的形貌,通过超景深金相显微镜观察纤维在复合材料中的分布并对复合材料的挤压过程进行分析。结果表明:镀镍碳纤维能满足制备的要求并有利于纤维在复合体中的均匀分散,在含4.0%(质量分数)碳纤维的预制体采用压制压力为420MPa,烧结温度为550℃保温0.5h后,在480℃用280MPa的压力进行热挤压得到材料的力学性能最佳。

Fabrication of Palladium-Free Nickel-Coated Carbon Fiber Reinforced Magnesium Alloy Composites by Powder Metallurgy Hot Extrusion and Their Microstructure

Chopped carbon fibers reinforced magnesium was made using the powder metallurgy technique followed by hot extrusion.In order to enhance the carbon fiber wettability to the matrix,the carbon fibers were nickel-coated by palladium-free activated electroless coating method and then characterized by field emission-scanning electron microscope(FE-SEM) equipped with energy dispersive spectroscopy(EDS).The fiber distribution in composite materials were evaluated by super depth digital microscope and the composite extrusion process was analyzed.The results show that nickel-plated carbon fibers can meet the requirement for the preparation and the dispersion in the composite.The composite containing 4.0wt% carbon fibers can obtain the optimum mechanical properties,and its preparation process is as fellows:its green is produced by applying 420 MPa pressure at room temperature,then consolidated by hot extrusion at 480 ℃ and 280 MPa pressure,and sintered at 550 ℃ for 0.5 h.