(北京科技大学 材料科学与工程学院, 北京100083)
摘 要: 采用粉末注射成形制备SiC预成形坯和铝合金无压熔渗相结合的技术， 成功制备出高体积分数且形状复杂的SiCp/Al复合材料零件。 研究了烧结工艺对SiC预成形坯开孔率和强度的影响规律， 并对所制备的复合材料的热物理性能进行了评价。 结果表明： 经1 100 ℃真空烧结8 h的SiC预成形坯开孔率可以达到99.6%， 抗压强度为0.57 MPa； 所制备的57％SiCp/Al复合材料相对密度为98.7％， 热膨胀系数为7.5×10-6 ℃-1， 与GaAs、 BeO的接近， 热导率为1.65×105 W/K， 与传统Cu(15%)/W相当， 是柯伐合金的10倍， 在密度上接近Al， 不到Cu/W的1/5。 由综合比较可以看出， 采用注射成形与无压熔渗相结合的制备工艺, 可以低成本制备综合性能优异的高体积分数SiCp/Al复合材料。
关键字: 铝基复合材料； 无压熔渗； 注射成形； SiC
（ School of Materials Science and Engineering,
University of Science and Technology Beijing, Beijing 100083, China）
Abstract: The high reinforcement volume fraction SiCp/Al composite parts with complex shape can be produced successfully by combination of powder injection molding (PIM) for SiC preform preparation and aluminum pressureless infiltration. The effect of sintering process on open porosity and strength of SiC preform was researched, and the thermo-physical characteristics of final composites were also evaluated. The results show that the best sintering process for SiC preform is 1100℃, 8 h in vacuum, by which the open porosity is 99.6% and the preform strength reaches 0.57 MPa. The thermo-physical characteristics of 57% SiCp/Al composites produced by this technique are as follows: the relative density is 98.7%; the thermal expansion coefficient is 7.5×10-6 ℃-1 which almost matches those of GaAs and BeO; the thermal conductivity is 1.65×105 W/K, which corresponds to that of Cu(15%)/W and decuples that of Kovar alloy; the density is close to that of aluminum and less than that of one fifth of Cu/W. So it is concluded that high reinforcement volume fraction SiCp/Al composites with good synthetic characteristics can be prepared economically by PIM-pressureless infiltration technology.
Key words: aluminum matrix composite; pressureless infiltration; powder injection molding; SiC
