(7-1) ( 2 points) In a two-component system, what is the theoretical maximum number of phases that can be in equilibrium? (7-2) (Total of 19 points) From the phase diagram of PbMg alloy shown below, (a) (2 points) Identify the degree of freedom at the following points: A, B, C, D (b) (17 points) consider equilibrium cooling from 600C, identify the following: phases, compositions (wt % ), weight percent (wt % ) of Phases and sketch microstructure (Label the phases in the microstructure) at the following temperatures: i. 75wt%Pb25wt%Mg, equilibrium cooling at 500C and 251C ii. 81wt%Pb19wt%Mg, equilibrium cooling at 251C and 100C ii. 90wt%Pb10wt%Mg, equilibrium cooling at: 251C and 249C