SINTERING BEHAVIOUR OF Al-4.5 percent Cu-15 percent Pb ADMIXED ALLOY

摘要

Aluminium-4.5 wt percent copper-15 wt percent lead powder mixture were prepared by mixing the required amounts of powders in a suitable blender. The powder fixtures were compacted at 98,196, 294 and 392 MPa in a single action steel die into pellets of 1 cm diameter and 1 cm length A mixture of silicone fluid and graphite was used for die wall lubrication. Sintering was done at 520,560 and 600 deg C for 30 minutes under dry nitrogen. Volume change on sintering, density, porosity, hardness and strength of sintered materials were measured as a function of compaction 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 compact was found to incrcase with increasing pressure and temperature. Sintering below eutectic temperature (520 deg C) resulted in < 0.8 percent volume increase whereas sintering above eutectic temperature (560 deg C and 600 deg C) resulted in a volume increase of 1.5 to 3.9 percent. Hardness of the Al- 4.5 percent Cu-15 percent Pb compact decreased on sintering at 520 deg C (below eutectic) and increased when sintered above eutectic (560 deg C and 600 deg C). Hardness of Al-15 percent Pb compact decreased at all sintering temperatures. These results indicate the positive effect of presence of eutectic liquid during sintering process.