THE ALLOYS OF ALUMINIUM AND LEAD

The equilibrium diagram of the system aluminium–lead exhibits two invariant points, the eutectic at 326.8° ± 0.1 °C., corresponding to 0.021% aluminium, and the equilibrium—two liquid layers–solid aluminium at 658.5° ± 0.1 °C.—the freezing points of pure lead and of aluminium being taken as 327.3° and 660.0 °C. respectively. The composition of the aluminium rich liquid at this point is 98.9% aluminium.The mutual solubility of liquid lead and aluminium is small below 800 °C. In the solid state, lead and aluminium are mutually insoluble. Liquid aluminium can take up as much as 10% lead in the form of an emulsion or colloidal suspension.The effect of the addition of lead on the hardness of aluminium has been investigated.