压铸法制造SiCw/Al复合材料的渗透过程分析

ANALYSIS OF INFILTRATION PROCESSES DURING THE FABRICATION OF SiCw/Al COMPOSITE BY SQUEEZE CASTING METHOD

本文深入分析了用压铸法制造SiCw/Al复合材料过程中液态铝渗入SiC晶须预制块中的渗透过程。通过理论计算得到液态铝渗入晶须预制块的临界渗透压不超过2MPa。对不同晶须含量的预制块所进行的模拟渗透过程的压缩试验结果表明,随外力的增加,预制块被压缩的程度增大,从而使预制块的晶须相对含量增大。通过对渗透过程的分析,认为液态铝渗透晶须预制块需要一定时间,因此当外力以较大的速度达到最大值时,液态铝不能完全渗入预制块中,这时预制块将被压缩,导致所得复合材料晶须相对含量提高。研究结果表明,复合材料晶须体积分数主要取决于预制块晶须体积分数和复合压力。

The infiltration processes of melt aluminium alloy into SiC whisker preform were analyzed during the fabrication of SiCw/Al composite by squeeze casting method. The infiltration pressure was calculated to be less than 2 MPa. The compressive tests of the SiC whisker preforms with different whisker volume fraction were carried out in the condition similar to that of the infiltration processes, and the experimental results showed that with the increase of the fabrication prefssure, the preform was compressed and so the volume fraction of whisker of the preform was increased.Based on the analysis of the fabrication processes, it was considered that it needs a period of time for the infiltration processes to be finished so that the preforms were compressed before they were infiltrated by melt aluminium when the fabrication pressure reached the maximum value, and therefore the volume fraction of whisker of preforms was increased. When the pressing speed was very high, the volume fraction of whisker of the SiCw/Al composite was mainly decided by the whisker volume fraction of preform and the fabrication pressure.