高体份SiC_p/Al复合材料型芯法无压浸渗近净成形制备技术

Near Net-shape Forming Technique with Mold Core of High Volume Fraction SiC_p /Al Composite in Pressureless Infiltration Process

选用表面热喷涂MgO涂层的铝合金型芯成功地实现了高体份SiCp/Al复合材料的无压浸渗近净成形制备。利用SEM,EDS,XRD等手段对SiCp/Al复合材料的组织结构、断口形貌和相组成进行了分析。分析结果表明:SiCp/Al复合材料与铝合金型芯之间无明显的异质界面相存在,浸渗复合过程中紧贴型芯处的SiC颗粒堆积体未发生过坍塌、溃散,颗粒分布均匀,表面涂层的存在使型芯很好地保持了形貌。型芯的使用不仅没有给复合材料带来成分的污染,通过测试、比较距离型芯约500μm处的复合材料与远离型芯的复合材料的弯曲强度、弹性模量、密度、线膨胀系数及热导率,证实了型芯的使用没有引起复合材料性能的劣化。另外,通过对型芯尺寸的合理控制,完全能够以无压浸渗法制备出型腔尺寸较为精准、形状规则的高体分SiCp/Al复合材料制件。

Near net-shape forming technique of high volume fraction SiCp /Al composites was realized by using aluminium-alloy-core with MgO coating in pressureless infiltration process.The microstructure,fracture surface morphology and phase constituent of SiCp /Al composite were analyzed by SEM,EDS and XRD.The results show that there was unobovious heterogeneous interface between SiCp /Al composite and aluminium-alloy-core,the SiC particles in composite near interface didn’t collapse and distributed uniformly,the use of core didn’t bring componential pollution to composite.The properties of composite near interface（about 500μm） and composite which is away from core including flexure strength,modulus of elasticity,density,coefficient of thermal expansion,thermal conductivity were tested,the results indicated the properties of composite near interface（about 500μm） and composite which is away from core didn’t appear significant differences and the use of core didn’t cause apparent degradation in property.The control on size was investigated and the result showed the high volume fraction SiCp /Al composite components with precise cavity was fabricated successfully by controlling reasonably the size of core in pressureless infiltration process.