(合肥工业大学 材料科学与工程学院，合肥 230009)
摘 要: 以F220、F500、F600这3种粒度的磨料级绿SiC混合粉为原料制成预制件，然后将其分别在500、1 100和1 200 ℃煅烧后无压熔渗液态铝合金制备SiC体积分数为62%~64%的铝基复合材料SiCp/Al；研究预制件煅烧温度对SiCp/Al复合材料结构和性能的影响。结果表明：不同温度下煅烧的SiC预制件渗铝后，都能获得结构均匀致密的复合材料；高温煅烧使SiC颗粒氧化形成骨架，导致强度从305 MPa降至285~245 MPa；SiC颗粒表面氧化转变成的SiO2薄膜增加复合材料中的陶瓷含量，使复合材料的热膨胀系数进一步降低；当SiC预制件中SiO2薄膜质量分数达到3.7%~6.7%时，SiCp/Al复合材料界面热阻增大4~6倍，复合材料热导率从184 W/(m·℃)降至139~127 W/(m·℃)。
关键字: SiCp/Al复合材料；预制件；氧化；强度；热学性能
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
