Aging Characteristics of Al P/M Composites with Variation of Ceramic Contents

The aging behavior of sintered Al composites with various ceramic contents was investigated. 2xxx series blended powder was used as the starting powder. Ceramic contents were 0 wt.% and 5 wt.%. The blended powders were compacted at 250 MPa. The sintering process was performed at 620oC for 60 min in a N2 atmosphere. After sintering, each part was solution-treated at 518oC for 60 min and aged at 180oC. The Rockwell hardness value at the peak aging time increased with increased ceramic contents. However, the peak aging time at maximum hardness was reduced with increased ceramic contents. The changes in aging behavior may have been caused by the acceleration of diffusion due to the strain induced by differences in the thermal expansion coefficients of the matrix and the ceramic phases.