Developing Carbon Particle Reinforced Alnmininm Composite byPowder Metallurgy

• Main Author: Mohtar, Mohamad Najib
• Format: Final Year Project
• Language: English
• Published: Universiti teknologi petronas 2008
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://utpedia.utp.edu.my/9910/1/2008%20-%20Developing%20Carbon%20Particle%20Reinforced%20Aluminium%20Composite%20by%20Powder%20Metallurgy.pdf; http://utpedia.utp.edu.my/9910/

Pure aluminium powder with average particle size of 25 um was pressed at 580 MPa reaching a green density of 97.5% theoretical density to form a circular disk. Sintering was carried out under argon gas atmosphere at 620°C for 3 hours. The effect of sintering conditions (temperature, time, and atmosphere) was evaluated by cutting the disk and hardness was measured. SEM and EDX were used to study microstructural characterisation and particle content of the sintered materials. To improve the properties ofpure aluminium disk, certain modification was made in the procedures. At this time, the aluminium powder was compacted with 464 MPa pressure to produce green density of92% theoretical density. Sintering was done under nitrogen gas atmosphere for 15 minutes at temperature of 630°C. After sintering, the properties ofsintered material were evaluated to compare with the first disk. The major different between these two samples isthe compaction and sintering properties used to develop the end products. During cutting process, the second sample sintered in nitrogen showed higher hardness than the first sample. For composite compaction, three samples were prepared with 3%, 4% and 7% ofcarbon in term of volume percent to be added to aluminium powder with addition ofwax as binder. By using 255 MPa compaction pressure, sample with 3% ofcarbon produced high strength green compact while there are some loose powder on the surface of another two samples. Sintering for the three samples was carried out under nitrogen atmosphere within two stages. Burn offprocess toremove wax at 350°C for one hour and sintering at maximum temperature of 620°C for one hour. The properties of composite material was evaluated using hardness test mid to be compared to properties of pure aluminium compact. The hardness of composite material is less than pure aluminium compact and it is suitable to use as self-lubricating material due to the present of carbon.