How to decrease overaging in Pb–Ca–Sn alloys?

It is known that lead–calcium–tin alloys are very well hardened by continuous precipitation since 20°C. But an overaging involving a decrease of the mechanical properties appears afterwards. It is proved in this study that with an adapted combination of the composition of the Pb–Ca–Sn alloys and a specific heat treatment it is possible to reach a hardness of 25 to 30 Vickers with a complete precipitation of (Pb1−xSnx)3Ca and to suppress practically any overaging in as-cast or rolled specimens.