In the concentration range 0-62.5 mol % A, A and B form three chemical compounds: AB12(s) dissolves at 632°C, the resulting solution has 17.4 mol % A. AB2(s) melts at 675°C. A5B3(s)
melts at 722°C.
There is a eutectic point at 18.9 mol % A and 622°C, and at 44.7 mol % A and 646°C.
There is no miscibility between the two solid phases, but complete miscibility in the liquid phase. All
the stated equilibrium data, which are measured by DTA (differential thermal analysis), apply at 1 atm.

A) Draw a Tz-diagram for the system A-B with mole percent A as abscissa (from 0-62.5 mol %)
and the temperature in °C as ordinate. Pure B melts at 850°C (1 atm). Indicate which phases
that correspond to different regions of the phase diagram.

1 mol A(s) and 9 mol B(s) is mixed together. The mixture is heated at constant pressure till
equilibrium is reached at 800°C. Then the energy in form of heat is removed at constant rate.

C) Draw the cooling curve, temperature versus time, for the equilibrium cooling at constant
pressure from 800°C to 500°C, and indicate the equilibrium relationship in different regions of
the drawn cooling curve. Calculate the amount of the phases, which are found at 500°C.