Physical and Quantitative Microstructural Analysis of Sintered Al-Cu/SiCp Composites

Abstract

Al-Cu matrix composite materials with 5-20 wt. proportions of SiC hard particles and un-reinforced Al-Cu alloys obtained by powder metallurgy (P/M), in the same homogenization (20 r.p.m., about 7 hours)– pressing (450 MPa for composites) - presintering (300-420oC/30 min/H2) conditions but at different sintering temperatures (520-620oC/60min/H2, furnace cooling) were analyzed in terms of microstructural and physical characteristics. The existence of good bonding between metallic matrix and ceramic particles at interface and the morphology and distribution of pores and carbides in the matrix was evaluated by means of quantitative analysis. Using computer-assisted Optic Quantitative Microscopy on the samples, we determined the pore surface area for the studied materials and the surface area and grain size distribution of the SiC particles of sintered composites by analyzing the captured images in many fields. The hardness were correlated with quantity pore surface area and resulted that the lowest values of porosity were achieved at 620oC and at 10 and 15% silicon carbide in matrix.