چكيده به لاتين
Closed cell aluminum foams are complex cellular materials which have attracted more and more attention due to their low density, excellent energy absorption performance, and effective noise reduction. Metal foams are quite a challenge to materials scientists due to difficulties in manufacturing and partially unknown structure relation to physical and mechanical properties. This study, stir casting technique is utilized to produce Silicon carbide/Aluminum alloy composite. To achieve a homogeneous and suitable distribution, different pre-treatments namely, thermal and mechanical treatments including oxidizing at 950˚C for 1 h, heat treating at 950˚C for 1 h then keeping at 650˚C for 2 h and milling with Al powder has been applied to SiC particles.Then 10% vol. of paricles with 2, 10 and 40 microns size were gradually added to the aluminum matrix. Composite with different volume percentage 5, 10 and 15% of 10 micron reinforcement were fabricated. Observing the composite microstructure using OM and SEM and reveals that reinforcing particles are suitably wetted and dispersed in the 10 micron particles oxidized at 950˚C for 1 h and 2 h at 650˚C. Aluminium alloy foams were produced by air injecting using single and several pores at 730˚C into liquid alloys containing 10 and 15% vol. SiC particles at 30, 40 and 50 cm3/min gas flux. In adition, air was injected to the 15% vol. composite at 700 and 760˚C. Macroscopic and microscopic observation of cell walls of foams were done and density, cell size and prosity were calculated. The Experimental results indicates that the cell size increses with increasing the gas flux along with reduction in density. Morever, the least density was 0.206 g/cm3 for sample with 15% vol. SiC which gas was blown in at 730˚C with 40 cm3/min flux. The samples wich were manufacrued with several pores had uniform and small pore structure.
Keywords: Metal foams, Aluminum foams, gas inejection, Aluminum/SiC composite, wetability
