The effect of low strain and annealing iterations on the ductility of alpha-brass

Abstract

This paper reports a study of the relationship between purpose-designed, iterative multi-stage thermomechanical treatments, grain boundary crystallography and subsequent ductility in alpha-brass. Grain boundary crystallographies were analysed not only in terms of proportions of coincidence site lattice (CSL) types but also, crucially, as proximity to the exact CSL reference structure. The only CSLs that were present in significant proportions were Σ3s, and those Σ3s with intermediate proximity to the exact CSL misorientation were identified as high mobility boundaries. Variation in mobility at a Σ3 as a function of deviation from the exact CSL configuration is discussed in detail. For two selected specimens modifying the strain-annealing regimes resulted in ductilities of 53% and 74% respectively. The enhanced ductility in one specimen is probably the result of a combination of strain-induced grain growth and increased proportions of Σ3s with intermediate proximity to the exact CSL misorientation.