Influence of precipitation on recrystallization and texture development in an iron-1.2% copper alloy

Abstract

The development of preferred orientation has been studied in this alloy for a wide range of annealing conditions which included single and two-stage treatments as well as continuous heating at various rates. The most strongly pronounced textures are formed after high rolling reductions and in annealing treatments which allow precipitation of copper to occur in the cold-worked structure prior to recrystallization. Fine-scale precipitation which can be produced by ‘light’ preliminary annealing treatments results in a coarse-grained condition after recrystallization with a high value of the texture ratio I ₂₂₂/I ₂₀₀. The same effect may be achieved by heating at an optimum rate of about 10 K min⁻¹. This behaviour resembles closely that of commercial aluminium-killed steels and is attributed to a reduction of the nucleation rate of recrystallized grains and an enhanced orientation selectivity.

Prolonged low-temperature annealing or very slow heating rates lead to a fine-grained recrystallized state with a strong {l00} <all> texture component. During these treatments, sub-boundary migration is initiated in regions of sharp lattice curvature resulting in a high concentration of coarse copper particles which inhibits continued movement of the boundaries. It is proposed that under these conditions, nucleation of recrystallized grains may occur by a process of extensive recovery within volumes of the deformation structure which exhibit very small lattice curvature.