抄録
Ba added Pb-Ca-Sn alloy has been applied as positive electrode grid material for automotive batteries due to its excellent mechanical properties, high corrosion resistance, good creep properties and recyclability. In our previous studies, it was clarified that Ba added Pb-Ca-Sn alloy had excellent mechanical properties by two-step aging treatment. However, age hardening behavior by the two-step aging treatment hasn't been revealed sufficiently. In addition, effect of two-step aging treatment on microstructure of this alloy has not been understood. In this present, therefore, we investigated changes of the age hardening behavior and the microstructure by two-step aging treatment. Samples were produced by solution treatment of as-cast Ba added Pb-Ca-Sn alloys. The solution-treated alloys were subjected to the two-step aging treatment, and age hardening curves were obtained from micro-Vickers tests. The microstructures were examined by transmission electron microscopy (TEM). From obtained age hardening curves, the maximum hardness increased with holding time in natural aging treatment. TEM observations confirmed that precipitates created by aging treatment were uniformly dispersed throughout crystal grain.
