List of Important Alloys and their Composition: (1) Aluminium Alloys (2) Copper Alloys (3) Magnesium Alloys (4) Nickel Alloys (5) Steel Alloys. (1) Aluminium Alloys: These are preferred to pure aluminium for constructional purposes. They are hard and strong. They contain copper, silicon, magnesium, manganese, iron and nickel in various combinations. Following are the important alloys of aluminium: (i) Aldural [...]
In this article we will discuss about the solidification of polycrystalline materials with its schematic diagram. A space lattice is formed by adding unit cells one after the other in three dimensions. It is possible to produce a macroscopic visible piece of a metal, formed by repetition of unit cells of crystal structure of that metal in three dimensions of [...]
In this article we will discuss about the shapes of phases with its diagram. Any surface or an interface such as a grain boundary has energy related with it, which acts like a surface tension. A solid phase does not easily change its shape in response to the surface tension (due to rigid bonds between atoms in a solid), unless [...]
In this article we will discuss about the phase diagrams that show solid-state phase transformations by using eutectoid and peritectoid reaction. 1. Eutectoid Reaction: Eutectoid reaction is best known for its occurrence in iron-carbon alloys, where it occurs because of the polymorphic transformation in iron, and is mainly responsible for the various types of heat treatments in steels. This reaction [...]
Al-Si diagram is a eutectic diagram where solid solubility at least of aluminium in silicon is negligible, and maximum solubility of silicon in aluminium (at eutectic temperature) is 1.65%. The eutectic composition is 12.7% silicon. Fig. 3.18 illustrates this diagram and photomicrographs of alloys at room temperature. Alloys of Al-Si are very important casting alloys mainly because of high fluidity [...]
In this article we will discuss about the phase diagram showing monotectic and syntectic reaction. Phase Diagram Showing Monotectic Reaction: In some alloy systems, two liquid solutions are seen to be immiscible (insoluble) only over a certain composition range, and in most cases (there are some exceptions), the mutual miscibility is found to increase with the rise of temperature. For [...]
In this article we will discuss about how to construct ternary diagram for solid solubility. Many useful metallic alloys (stainless steels, aluminium-based age-hardenable alloys contain not just two important components, but three or more to obtain much greater improvements in the properties. Metals for high temperature services may contain ten important elements. Thus, most commercial alloys are more complex than [...]
In a eutectic reaction, when a liquid solution of fixed composition, solidifies at a constant temperature, forms a mixture of two or more solid phases without an intermediate pasty stages. This process reverses on heating. In a eutectic system, there is always a specific alloy, known as 'eutectic composition' that freezes at a lower temperature than all other compositions. At [...]
List of important alloys of steel: 1. Silicon Steel 2. High Speed Tool Steels 3. Heat Resistant Steels 4. Spring Steels 5. Stainless Steel 6. Chrome Vanadium Steels 7. Nickel Steel 8. Vanadium Steel 9. Manganese Steel 10. Tungsten Steel 11. Magnet Steels. 1. Silicon Steel: A. Silicon improves considerably the electrical properties of steel. B. Silicon imparts fatigue strength [...]
An alloy may be defined as coherent metallic mass produced by the intimate association of two or more metals. In some cases also the introduction of non-metals such as carbon, silicon, phosphorus, boron, sulphur and even nitrogen or oxygen may produce marked effects. It is important that thousands of combinations resulting in useful alloys are possible. Important non-ferrous alloys are [...]