Patents
The invention provides an inexpensive and easily accomplishable process for the in-situ preparation of MgAl2O4 reinforced Al alloy matrix composites using amorphous silica (SiO2) sources containing more than 90% of amorphous silica and more reactive than crystalline silica such as (i) silica gel, (ii) micro silica and (iii) rice husk ash, greater than 95%pure Al and 99.9% pure Mg as the starting materials. The addition of silica source in Al-Mg alloy at a temperature in the range of 690-730°C is carried out through vortex method. The subsequent holding of the molten melt is done at 700-800°C for 2-3 hrs. The product crystals of MgAl2O4 are achieved inside an Al-Mg-Si alloy by the exothermic reactions taking place between silica sources and other constituents in the molten alloy. Thus, the final composite i.e., Al-Mg-Si alloy reinforced with an appreciable amount of 2-10 microns sized MgAl2O4 crystals is realized economically in a time span of 2-3 hrs.