DEVELOPMENT OF TEXTURE AND MICROSTRUCTURE DURING ROLLING OF THE COPPER 8 WT PCT GERMANIUM ALLOY

Abstract

A comprehensive description of processes occurring during the plastic deformation requires confrontation of the variation of texture with the accompanying changes in microstructure and physical properties. However, the variation of texture and microstructure in low stacking fault energy f.c.c, metals and alloys has not been till now well recognized as investigations were generally limited to texture analysis at high rolling reductions Not enough attention has also been paid to the effect of initial texture and grain size, and to the influence of geometry of the rolling gap on inhomogeneity of texture and microstructure. Equally, the commonly used method of series expansion for the quantitative description of texture does not allow a satisfactory identification of texture details, especially in lower levels of orientation density. The orientation distribution function is then burdened with truncation errors and those ensuing from the phenomenon of ghosts; the ghosts are observed in the ODF in the positions which are in twin relations with the pronounced components, and mechanical twinning is a very important process in the deformation of low stacking fault energy metals and alloys. In the present research the rolling has been carried on with unit draughts generally not much smaller than 0.5 and not greater than 5. In these conditi.ns the texture does not exhibit the through-thickness inhomogeneity-. Texture analysis has been carried out on samples from the central layer of the rolled material when applying the direct ADC method bae on discretization, in which the above described errors do not appear For all experiments the copper 8 wt pct germanium alloy was used, rolled from the annealed state up to 98 pct reduction. In the initial state the alloy was characterized by a rather sharp texture, and the mean grain size was 95 /m. The stacking fault _energy determined by the dislocation nodes method was equal to 10 mJ/m-.