(合肥工業(yè)大學 材料科學與工程學院，合肥 230009)
摘 要: 以F220、F500、F600這3種粒度的磨料級綠SiC混合粉為原料制成預制件，然后將其分別在500、1 100和1 200 ℃煅燒后無壓熔滲液態(tài)鋁合金制備SiC體積分數(shù)為62%~64%的鋁基復合材料SiCp/Al；研究預制件煅燒溫度對SiCp/Al復合材料結(jié)構和性能的影響。結(jié)果表明：不同溫度下煅燒的SiC預制件滲鋁后，都能獲得結(jié)構均勻致密的復合材料；高溫煅燒使SiC顆粒氧化形成骨架，導致強度從305 MPa降至285~245 MPa；SiC顆粒表面氧化轉(zhuǎn)變成的SiO2薄膜增加復合材料中的陶瓷含量，使復合材料的熱膨脹系數(shù)進一步降低；當SiC預制件中SiO2薄膜質(zhì)量分數(shù)達到3.7%~6.7%時，SiCp/Al復合材料界面熱阻增大4~6倍，復合材料熱導率從184 W/(m·℃)降至139~127 W/(m·℃)。
關鍵字: SiCp/Al復合材料；預制件；氧化；強度；熱學性能
high volume fraction SiCp/Al composites
（School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China）
Abstract:The SiC performs were prepared by green SiC powder containing three kinds of particle size of F220, F500 and F600, and by aluminum matrix composites reinforced by SiC powder (volume fraction of 62%−64%) were produced by the pressureless infiltration of liquid aluminum alloy into the SiC performs which were calcined at 500, 1 100 and 1 200 ℃, respectively. The effects of calcination temperature on the structure and properties of SiCp/Al composites were investigated. The results show that SiCp/Al composites are all uniform and impact as SiC preforms calcined at different temperatures. When sintered at high temperature, SiC particles are oxidized to form skeleton which leads the bending strength of SiCp/Al composites decreasing from 305 MPa to 285−245 MPa. The SiO2 film transformed from SiC by oxidation promotes the ceramic content in the composites, which results in further decrease of the thermal expansion coefficient of SiCp/Al composites. The interface thermal resistance of SiCp/Al composites increases by 4−6 times due to 3.7%−6.7% (mass ratio) SiO2 film in the SiC preforms, and the thermal conductivity of SiCp/Al composites decreases from 184 W/(m·℃) to 139−127 W/(m·℃).
Key words: SiCp/Al composites; preforms; oxidation; strength; thermal properties
