Metals have been used in many fields in common life as well as in industry, and they requires the various and specific properties according to application, such as strength, hardness, toughness, density, brightness, solubility, expansion coefficient, ...
Metals have been used in many fields in common life as well as in industry, and they requires the various and specific properties according to application, such as strength, hardness, toughness, density, brightness, solubility, expansion coefficient, electrical and thermal conductivity, and corrosion resistance for chemical agents and atmosphere. However, it is very difficult or impossible that one pure metal shows all the above mentioned properties, and its properties are restricted because of the limited number of metallic elements. The desirable properties could be satisfied by alloying with two and more elements. The characteristics of alloys can be changed with the kind and amount of additive element, and temperature. Therefore, the choice of alloying conditions-composition and temperature is a critical problem to obtain the required properties. Equilibrium phase diagrams for alloys provide proper solutions, which help one to understand and predict the properties of materials.