A metal material having a metallic property formed by alloying processes (melting, mechanical alloying, sintering, vapor deposition, etc.) of two or more metal elements or other non-metal elements based on a metal is often called an alloy. . But the alloy may contain only one metal element, such as steel. (Steel, a general term for ferroalloys with a carbon content of between 0.02% and 2.00% by mass)
Here we need to note that the alloy is not a general conceptual mixture, it can even be a pure substance, such as a single phase intermetallic compound, the added alloying elements can form solid solutions, compounds, and produce endothermic or exothermic reactions, thereby changing the metal. The nature of the matrix.
The formation of alloys often improves the properties of elemental elements, for example, the strength of steel is greater than its main constituent element, iron. The physical properties of the alloy, such as density, reactivity, Young’s modulus, electrical conductivity and thermal conductivity, may be similar to the constituent elements of the alloy, but the tensile strength and shear strength of the alloy are usually related to the properties of the constituent elements. with large differences. This is due to the large difference in the arrangement of atoms in the alloy and the elemental substance.
A small amount of an element may have a large effect on the properties of the alloy. For example, impurities in ferromagnetic alloys can change the properties of the alloy.
Unlike pure metals, most alloys do not have a fixed melting point. When the temperature is between the melting temperature range, the mixture is in a solid-liquid state. Therefore, it can be said that the melting point of the alloy is lower than that of the component metal. See eutectic mixture. Among the common alloys, brass is an alloy of copper and zinc; bronze is an alloy of tin and copper for statues, ornaments and church bells. Alloys (such as nickel alloys) are used in some countries’ currencies.