A grain boundary engineering approach to promote special boundaries in Pb-base alloy

A grain boundary engineering approach was made to improve the microstructure of a commercial Pb-base alloy for better performance in automobile battery application. For the purpose of enhancing the resistance against intergranular corrosion, cracking and creep, a thermomechanical processing route was sought to promote special boundaries, specifically coincidence site lattice (CSL) boundaries. Through a combination of cold working and recrystallization heat treatment, it was possible to increase the fraction of low ΣCSL boundaries more than 91%. Annealing twins, produced during the thermomechanical processing, were identified as a key factor for regeneration of CSL boundaries. Multiplication of the CSL boundaries was interpreted in terms of the ‘Σ3 regeneration’ model proposed by previous authors.