So in this video I'm going to show you how to go about constructing a phase diagram from a written description. You can find this written description below in the attached files and try this for yourself and see how you got on. I'm going to have a go here. So I'm given a series of information here. We have two components A which melts at 1750, B which melts at 1650 degrees C, A3B which melts in congruently at 1400 degrees C, AB which melts congruently at 1500 degrees C, AB4 which is stable between 1,200 degrees C, and then we're given two eutectic points as well, E1 at 1300 degrees C, 40% B, and E2 at 1350 degrees C, 80 more percent B. So let's have a go at writing that up. So we've got A which we know melts here at about 1750. Is that a bit bigger? B, our component over here melts around about 1650. Okay, now the one neat thing we have here is a congruently melting phase. So let's deal with that first. Congrently melting phases can be used to divide the phase diagram into different sections. So if we have a phase in the middle around about here which is A, B, we know that melts congruently at 1500 degrees C which is going to be about there. So we can draw on that line. So straight away we've divided the system up into two different sections. We then know that we've got another phase A3B which melts incongruently at 1400. So A3B is 25% B, 75% A, so it should be about here. So A3B and that melts incongruently at 1400. So we know it's going to look something like that. Okay, so we've got this classic T-shape from an incongruently melting phase. Next we've got one final intermediate phase which is A, B, 4 which is 80% B. So we can put that somewhere over here. So A, 4, B. And we're told that that is only stable between 1,000 and 1,200 degrees C. This often catches a lot of people out when I do this sort of question. So 1,000 is there, 12,000 is there. So the line stability for this line phase only extends over that region. And that means that we can also draw on lines top and bottom. Okay, so we've then got two eutectic points. The first one is at 40B. So somewhere about here at 1300 degrees, should be about there. So if it's a eutectic, we've got a line going through it. And another eutectic at 80% B, 1350 degrees C. So that's directly above A, 4B, somewhere about there. And again, we know it's a eutectic, so we can put another straight line. And then it's a simple case of joining the dots. So we know this needs to come down from A through the peritectic point here and onto the eutectic. We don't know from the information we're given exactly where this peritectic point should be. But it doesn't matter, we can make a reasonable guess. And we won't be far off. And then it goes up to the congruent melting AB phase. And over to the next eutectic and up to B. And so we've got a reasonable shape for our eutectic. It might for our liquidus, sorry, it might not be perfect, but it's a realistic shape. It's pretty reasonable guess. And then we can just go through and label up some of these regions. So in here we have A plus A3B, A3B plus AB. AB plus B. And in here we have AB plus B. That's the part that often catches people out. Down here we have AB plus A4B. And in this little region here, A4B plus B. Then AB plus liquid, B plus liquid, A plus liquid, liquid at the top. A3B plus liquid here. And the same in here. And so there you have a constructed and labeled phase diagram from a very brief description here.