SINTERING BEHAVIOR OF AL-4.5-PERCENT CU-15-PERCENT PB ADMIXED ALLOY

Alumininm-4.5 wt% copper-15 wt% lead powder mixture were prepared by m ixing the required amounts of powders in a suitable blender. Tile powd er mixtures were compacted at 98, 196, 294 and 392 MPa in a single act ion steel die into pellets of 1 cm diameter and 1 cm length. A mixture of silicone fluid and gaphite was used for die wall lubrication. Sint ering was done at 520, 560 and 600 degrees C for 30 minutes under dry nitrogen. Volumee change on sintering, density, porosity, hardness and strength of sintered materials were measured as a function of compact ion pressures and sintering temperatures. Strength and hardness of the sintered products were found to increase with increasing pressure and temperature. Density increased and porosity decreased with increasing pressure whereas there were slight increases and decreases in density and porosity respectively with increasing temperature. Volume of comp act was found to increase with increasing pressure and temperature. Si ntering below eutectic temperature (520 degrees C) resulted in <0.8% v olume increase whereas sintering above eutectic temperature (560 degre es C and 600 degrees C) resulted in a volume increase of 1.5 to 3.9%. Hardness of the Al-4.5% Cu-15% Pb compact decreased on sintering at 52 0 degrees C (below eutectic) and increased when sintered above eutecti c (560 degrees C and 600 degrees C). Hardness of Al-15% Pb compact dec reased at all sintering temperatures. These results indicate the posit ive effect of presence of eutectic liquid during sintering process.