Homework 8a - Phase Diagrams edit

(c) At what temperature does complete melting of the alloy occur? - 1380C (d) What is the composition of the last solid remaining prior to complete melting? - α + L: 79% Ni 9.15 For an alloy of composition 74 wt% Zn-26 wt% Cu, cite the phases present and their compositions at the following temperatures: 850C, 750C, 680C, 600C, and 500C - 850 - Phase: Liquid - Composition: 74% Zn 26% Cu - 750 - Phase: y + liquid - Composition: y: 67% Zn 33% Cu Liquid: 77% Zn 23% Cu - 680 - Phase: δ + Liquid - Composition: δ: 73% Zn 27% Cu Liquid: 82% Zn 18% Cu - 600 - Phase: δ - Composition: δ: 74% Zn 26% Cu - 500 - Phase: y + Ɛ - Composition: y: 69% Zn 31% Cu Ɛ: 78% Zn 22% Cu 9.16 Determine the relative amounts (in terms of mass fractions) of the phases for the alloys and temperatures given in Problem 9.10 a, b, c, d, e (a) 90 wt% Zn-10 wt% Cu at 400C (750F) - 𝜀 : (97-90)/(97-87) = 0.70 or 70% - 𝜂 : (90-87)/(97-87) = 0.30 or 30% (b) 75 wt% Sn-25 wt% Pb at 175C (345F) - α: (97-75)/(97-16) = 0.27 or 27% - 𝛽 : (75-16)/(97-16) = 0.73 or 73% (c) 55 wt% Ag-45 wt% Cu at 900C (1650F) - L: 1 because it is only one mass fraction so 100% (d) 30 wt% Pb-70 wt% Mg at 425C (795F) - Also 1 for the same reason as previous (e) 2.12 kg Zn and 1.88 kg Cu at 500C (930F) - 𝛽 : (58-53)/(58-49) = 0.56 or 56% - Y: (53-49)/(58-49) = 0.44 or 44%