================ 10.7 A 50 wt% Ni50 wt% Cu alloy is slowly cooled from 1400C (2550F) to 1200C (2190F). (a) At what temperature does the first solid phase form? —-> Upon cooling form 1400C, the first solid phase forms at the temperature at which this vertical line intersects the L(a + L) phase boundary. (b) What is the composition of this solid phase? —->The composition of this solid phase corresponds to the intersection with the L(a + L) phase boundary, of a tie line constructed across the a + L phase region at 1320C. (c) At what temperature does the liquid solidify? —-> Complete solidification of the alloy occurs at the intersection of this same vertical line at 50 wt% Ni with the (a+ L)a phase boundary. (d) What is the composition of this last remaining liquid phase? —-> The composition of the last liquid phase remaining prior to complete solidification corresponds to the intersection with the L(a+ L) boundary, of the tie line constructed across the a+ L phase region at 1270C