ABSTRACT
This chapter examines the internal structures of different types of the alloy and shows that at what extent the structures of these alloys can influence their mechanical properties. The eutectic aluminium-silicon alloys consists of the layers that are hard, brittle, silicon sandwiched between layers of the soft, tough aluminium and the tensile strength of these cast aluminium silicon alloys is much higher than that of the pure aluminium. The brick-wall analogy illustrates, that the folly of viewing a microstructure at a high magnification, without examining it with a low-power lens in the microscope. The process of diffusion takes place by a series of successive 'moves', as suggested in the substitutional solid solution. Many metals combine with oxygen to form compounds that is called as oxides, whilst that some metals are attacked by sulphur gases in furnace atmospheres to form sulphides when the metal is heated.
