Hardening mechanism in lead-calcium alloys

Hardening mechanism in lead-calcium alloys. Lead-calcium alloys harden extremely rapidly 80% of the ultimate strength is reached in one day, and virtually full ageing in seven days. Such rapid hardening enhances grid handling and battery production. The rapid hardening was a benefit to VRLA batteries. 

As the grain boundaries move through the casting, they are trapped on defects and impurities. This can result in boundaries that are more prone to corrosion. It has been suggested [25] that heat treatment of the alloy can redissolve the PbsCa particles near the boundary and, thereby, reduce the rate of corrosion of the alloy. Certainly, the mechanical properties, creep rate, and corrosion rates of lead-calcium alloys are 

Calcium (wt.%) Yield strength (MPa) Tensile strength (MPa) YSrUTS Creep to failure at 20.7 MPa (h) Corrosion rate (mm per year) 

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