微波烧结SiC-Cu/Al复合材料的工艺及机理

用微波烧结工艺成功制备了铜包裹碳化硅颗粒增强铝基(SiC-Cu/Al)复合材料,利用扫描电镜和X射线衍射分析仪对烧结样品进行表征,并讨论了烧结过程及机理.研究表明:采用多晶莫来石纤维棉、硅碳棒和氧化铝坩锅组合设计的保温结构能很好地促进烧结.烧结温度为720℃时,SiC-Cu/Al复合材料的密度取得最大值为2.53g/cm3.SiC-Cu/Al复合材料的硬度随烧结温度的升高的变化成马鞍状.烧结温度对样品显微结构的影响较大,随着烧结温度的升高,相分布的均匀性降低,在较高的烧结温度下会出现SiC颗粒的偏聚.涡流损耗和界面极化损耗是促进微波烧结的主要动力.

PROCESS AND MECHANISM OF MICROWAVE SINTERING OF SiC-Cu/Al COMPOSITES

Aluminum matrix composites reinforced by silicon carbide/copper coated particles (SiC-Cu/Al) were prepared using microwave sintering. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to characterize the sintered compacts. The process and mechanism of microwave sintering were discussed. It was found that the assistant-heating structure which was set up by mullite heat-preservation material, silicon carbide (SiC) rods and alumina crucible can effectively enhance the process of densification during sintering. The highest density of SiC-Cu/Al composites was 2.53 g/cm3 at 720 ℃. The saddle-shaped profile of the hardness with sintering temperature was detected. Correspondingly, different microstructures were observed at different temperatures. The uniformity of disturbed phases decreased with increasing temperature. Segregation of SiC grains occurred at high temperatures. Induction losses caused by both eddy currents and interfacial polarization were contributed to successful sintering.