Investigating the effects of SiC particles addition and thermal treatment on 90% Al- 10% Cu alloy

Abstract

Investigation of the effects of SiC particles addition and thermal treatment on 90Al-10Cu alloy has been undertaken. The work produced 90Al-10Cu Alloy and further produced test castings to which particle additions of SiC were added in the order 0.5%SiC, 1%SiC, 2%SiC and 4%SiC to see the effects of a wider variation in particle addition. These additions were made using stir-cast method to produce the test sample bars. The test sample bars were then taken to the University of Uyo, Faculty of Engineering workshop to prepare the test specimens into standard specifications for various tests. Some of the prepared test specimens were then given thermal treatment called age hardening. The specimens were first solutionised in the furnace at 500 oC (500 C) and quenched in warm water at 60C. It was then aged at 170C for three hours before cooling in air. It was after this treatment that the test specimens were subjected to hardness test, wear resistance test, strength test, and microstructure analysis. The result of the work showed that the thermal treatment had effect on the microstructure of all the samples. The result also showed that the SiC particle addition also affected the mechanical properties of the specimens. For the untreated compositions the alloy and 90Al-10Cu/2%SiC particulate composite had the lowest wear rate value of 0.0212mm3/N/m. 90Al-10Cu/1% SiC had the highest hardness value of 67.38 BHN. 90Al-10Cu/0.5%SiC particulate composite outperformed other compositions with the following mechanical properties: hardness value of 64.28BHN; ultimate compression strength of 217.18N/mm2; % reduction at failure of 3.01; and wear rate value of 0.0633 mm3/N/m. For the thermally treated compositions; the lowest wear rate of 0.0246mm3/N/m is with the alloy composition and 90Al-10Cu/2%SiC particulate composite. 90Al-10Cu/1%SiC particulate composite has the highest hardness value of 82.02BHN; the highest % reduction at failure of 1.13%, and wear rate value of 0.05982, while 90Al-10Cu/0.5%SiC particulate composite has hardness value of 80.12BHN, ultimate compression strength of 240.95N/mm2, % reduction at failure of 1.06%, and wear rate of 0.0895mm3/N/m. The 1% SiC reinforced particulate composite performed better than other compositions, but it is closely followed by 0.5%SiC reinforced particulate composite for the thermal treated compositions in terms of improved mechanical properties. This correlates with their microstructures which all show the precipitation of a second phase.