1. Problem Statement: We need to create and analyze a binary phase diagram for the Magnesium-Lead (Mg-Pb) system, showing the eutectic point and various phase regions, along with practical implications such as limited solubility and why these alloys are uncommon for structural use. 2. Understanding Binary Phase Diagrams: A binary phase diagram plots temperature (y-axis) versus composition (x-axis) for two components—in this case, Mg and Pb. 3. Components and Solubility: Mg and Pb have very limited solid solubility in each other, resulting in distinct phase regions and a eutectic point. 4. Sketching the Binary Phase Diagram: - The diagram has pure Mg on the left (0% Pb) and pure Pb on the right (100% Pb). - Each component has its own liquidus and solidus lines. - Between these lines are phase fields for liquid (L), primary solid phases (Mg-rich and Pb-rich), two-phase regions (L+Mg solid or L+Pb solid), and the eutectic region where both solid phases coexist. - The eutectic point is the lowest temperature where liquid coexists with both solid phases. 5. Key Features: - Eutectic temperature $T_e$ is a constant temperature where liquid transforms into two solids simultaneously. - Limited solubility leads to nearly vertical phase boundaries. - Phase regions include: • Liquid (L) • Mg-rich solid ($\alpha$) • Pb-rich solid ($\beta$) • Two-phase mixtures (L + $\alpha$, L + $\beta$, and $\alpha$ + $\beta$ below $T_e$) 6. Practical Implications: - Because of limited solubility, Mg-Pb alloys have poor mechanical properties and are not commonly used structurally. - Eutectic microstructure affects hardness and brittleness. - Use is limited to specialty applications if any due to incompatibility. 7. Final Summary: The Mg-Pb phase diagram reveals a classic eutectic system with limited solubility, noted by distinct phase fields and a eutectic point highlighting the simultaneous crystallization of Mg-rich and Pb-rich solids. Answer: The Mg-Pb binary phase diagram features a eutectic point at approximately a low intermediate temperature, distinct phase regions for Mg and Pb rich solids with very limited mutual solubility, and a two-phase eutectic region below $T_e$ where liquid transforms into both solids simultaneously.