 Hello friends. Today, I am going to deal with further part of study of binary equilibrium diagrams. I am P. P. Mitra Uthri from Vulturenistrop Technologies, Olappur. I am assistant associate professor at mechanical engineering department. So, at the end of this session, students will be able to analyze solidification behavior of various compositions in the alloy system as well as they will be able to interpret the significance of various transformations taking place in binary alloy systems. So, in the earlier session, we have discussed equilibrium diagram for isomorphous system. Isomorphous system is one in which all the compositions often in such alloy system are completely mutually soluble in each other in liquid state as well as in solid state. Today, we are going to study another equilibrium diagram that is equilibrium diagram for the system exhibiting partial solubility or partial solubility in solid state. In such system, all the alloys will not be solid solution alloys, but some of the alloys will be non-solid solution alloys unlike in isomorphous system of alloys. Now, to construct equilibrium diagram of such type, we need to have some data. So, let us assume the two metals A and B. Let m p of A be 1000 degree Celsius and let m p of B be 800 degree Celsius. Let B is soluble in A up to 8 percent at 766 degree Celsius and let B is soluble in A up to 2 percent at 0 degree Celsius. Similarly, let A be soluble in B up to 4.5 percent at 766 degree Celsius and let A be soluble in B up to 1.5 percent at 0 degree Celsius. And in such system, there will be one eutectic point and eutectic will occur at 766 degree Celsius and at 46 percentage of B. So, with this data, we will construct the equilibrium diagram exhibiting partial solid solubility. This diagram will be like this. Percentage B will be on x axis, temperature will be on y axis. Let us mark 1000 degree melting point of A and 800 degrees melting point of B at extreme ends. Then at one end, there will be 100 percent A. At another end, there will be 100 percent B. I will mark 0.46 percent B. Then the diagram will be like this. A, B, C will be liquidous line. A, D, B, E, C will be solidous line. Now, in this case, above liquidous line, there will be liquid phase. In between this region, there will be solid solution alpha, which is nothing but that. It is solid solution of solute B in solvent A. While on other end, there will be solid solution beta, which is solid solution of solute A in solvent B. Then in this region, there will be liquid plus alpha. In this region, there will be liquid plus beta. In this region, there will be alpha plus eutectic. While in this region, there will be beta plus eutectic. This temperature is 766 degrees Celsius. This line is solidous line. Line DF and EG are solvers lines, which indicate lines of limiting solubility in solid state. Now, in this case, there are three types of alloys. Alloys, before that, I will mark the percentages over here. So, in this case, if you look to this diagram, we will see that there is group one alloys. In group one alloys are the alloys, which contain up to 2 percent B and more than 98.5 percent B. These alloys solidify as solid solution and retain their solid solution structure even at room temperature. This is group one alloys. Another group of alloys is alloys, which solidify as solid solution, but are unable to retain solid solution structure at room temperature. These are the alloys containing more than 2 percent B and up to 8 percent B and more than 95.5 percent of B and up to 98.5 percent of B. These are group two alloys. While group three alloys are the alloys, which contain more than 8 percent B and up to 95.5 percent B. These are group three alloys. All these group three alloys are non-solid solution alloys in that there are three types. One is hypo eutectic. Hypo eutectic alloys are the alloys containing more than 8 percent B and up to 46 percent B. While hypo eutectic alloys are the alloys, which contain more than 46 percent B and up to 95.5 percent B, while eutectic alloys is one which contain 46 percent B. Now in this case, if we consider alloys having up to 2 percent B and more than 98.5 percent B can be hot worked as well as cold worked. But alloys containing more than 2 percent B and up to 8 percent B cannot be cold worked, but by heating them above solvus line, we can hot work them very easily. And group three alloys are non-solid solution alloys. They have fixed solidus temperature and variable liquidus temperature and their liquidus temperature is much lower than group one and group two alloys. So they have lower freezing range and such alloys can only be cast. They have excellent casting properties. They can neither be forged nor be rolled nor be extruded. And with this, I conclude study of equilibrium diagram having partial solution. So references for this study are material science and metallurgy by Dr. V. D. Kodegiray and introduction to engineering materials by B. K. Agarwal. Thank you once again.