HARDENING PROCESS IN TERNARY LEAD-ANTIMON Y-CADMIUM ALLOYS FOR LEAD-ACID-BATTERY GRIDS

It is known that the oversaturated quenched lead-antimony alloys are v ery well hardened by continuous precipitation, whereas lead-cadmium al loys present a discontinuous precipitation with a weak hardening effec t. In these binary alloys, there is precipitation of either antimony o r cadmium. In ternary alloys, the compound SbCd can also precipitate. This study is focused on the type of precipitation, the nature and the morphology of the precipitated phases, and the intensity of hardening in ternary Pb-Sb-Cd alloys in relation with the composition of the al loys and the ternary diagram and in parallel to the alloys of the Pb-S b-Sn system. To simulate the different processes of grid production, f our states are studied, namely as-cast product, rehomogeneized, cold w orked, cold worked and rehomogeneized. The alloys contain up 3 wt % ca dmium and antimony.