Quite a large number of phase diagrams of metal systems are available, but repeated investigations, with refinements in apparatus and techniques, lead to their frequent revision. No one method is best for all alloy systems, or even to locate all the boundaries in one alloy system. A diffusion couple is used to get the number and the order of the [...]
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 [...]
The following points highlight the four main types of binary diagrams. The types are: 1. Solid Solution Systems 2. Insoluble in the Solid State 3. Soluble in the Solid State 4. Peritectic Reaction. Binary phase diagrams are based on two component systems. Here, the two components may be mixed in an infinite number of different proportions, that is, composition also [...]
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 this article we will discuss about:- 1. Introduction to Phase Diagram 2. Phase Rule 3. Prediction 4. Uses 5. Limitations. Introduction to Phase Diagram: As the properties of a material depends to a large extent on the number, amount, type and the form (shape and the size) of the phases present, and can be altered by changing these quantities, [...]
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 [...]