EFFECTS OF STIRRING TIME AND PARTICLES PREHEATING ON POROSITY, MECHANICAL PROPERTIES AND MICROSTRUCTURE OF PERIWINKLE SHELL-ALUMINIUM METAL MATRIX COMPOSITE (PPS-ALMMC)

• Published in: Annals of Faculty Engineering Hunedoara 2017-08, Vol.15 (3), p.133
• Main Authors: Umunakwe, R, Okoye, O C, Nwigwe, U S, Oyetunji, A, Umunakwe, I J
• Format: Article
• Language: English
• Subjects: Aluminum; Aluminum base alloys; Die casting; Ductility; Heating; Homogeneity; Liquidus; Mechanical properties; Metal matrix composites; Microstructure; Particulate composites; Porosity; Process parameters; Semisolids; Solid state; Stirring; Toughness
• ISSN: 1584-2665; 2601-2332

The effects of some process parameters on the properties of PPS-AlMMCs were investigated. Periwinkle shells were milled to 75μm particle size and the density of the particles determined. The particulate periwinkle shells (PPS) were used to reinforce aluminium 6063 alloy at 10wt% filler loading using two-step stir casting technique. Each specimen was stirred for five minutes in a semi-solid state before reheating to temperature above the liquidus, varying the stirring time for 3, 6 and 9 minutes respectively and casting in a metal die. A specimen was also produced with pre-heated filler. The effects of variation in stirring time and reinforcement pre-heating on the porosity, microstructure and mechanical properties of the composites were investigated. The results of the analysis show the composites possess lower density than the alloy and the addition PPS to aluminium alloy improves the strength, ductility and toughness over those of the alloy. The stirring time affects the way the PPS disperse in the matrix, the composites chemical homogeneity and mechanical properties. The best combination of chemical homogeneity, lowest porosity, and optimal improvement in strength, ductility, toughness was achieved when the composite materials was stirred for six minute above the liquidus temperature compared to the other specimens.