1.1 MicrostructuresWhen metals are in solid form they are crystalline. The crystalline structure of a metal refers to the internal structure or arrangement of atoms in ordered, repetitive, or three-dimensional patterns. Normal metallic objects contain a collection of very small crystals that make them polycrystalline. These crystals are grains. Casting is an example of a metallic object that has large grains that can be resolved with the naked eye and these structures are called macrostructures (Copper Development Association Inc, 2013). Typically the grains of a metallic object are very small and cannot be seen with the naked eye. An optical microscope or an electron microscope is used to observe the structural characteristics of small grains at magnifications greater than 100 times. Structures that require this magnification range are called microstructures (Copper Development Association Inc, 2013). Figure 1 Microstructure of aluminum titanate Structure is the most important aspect of a technical material. The structure of a material is related to its composition, performance, properties and processing history. Therefore the microstructure of a material provides information linking its composition and processing to its properties and performance. Physical metallurgy is the science that provides an explanation of microstructures, through what happens inside a metal during various processes. Metallography is the science of preparing samples, examining them under a microscope, and interpreting microstructures (Copper Development Association Inc, 2013). Microstructural analysis is used to gain insight into how the material was produced and the quality of the resulting material… ... middle of paper ... there is an effect on temperature and cooling method. Annealing is used to remove the effect of solution heat treatment so that the workmanship or workmanship qualities can be improved (property identification and heat treatment of metals)1.4.2 Solution heat treatmentSolubility heat treatment involves the heating an alloy to a specific temperature for a specific length of time so that the alloying elements enter solid solution and form a single phase. The final properties of the alloy can be influenced by the temperature and time of immersion and the rate of cooling. The immersion temperature depends on the various phases within the alloys, each of these phases will dissolve into solid solution at different rates. The immersion time depends on the rate of dissolution of the alloying elements in the solid solution and the conditions under which the alloy was cast. (Coimbatore, Tamil Nadu, 2001)