Comparison of Contributions of the Mechanisms of the Superplastic Deformation of Binary and Multicomponent Brasses

The microstructural changes on the surface of the samples of a binary brass and of brasses alloyed with iron and manganese or aluminum, taken place in the process of superplastic deformation at 550 degrees C at a constant strain rate of 1 x 10(-3)s(-1)have been analyzed in this work. The contributions of the intergranular and intragranular deformation to the total elongation have been determined. It has been shown that the additional alloying of brass leads to a decrease in the contribution of the grain boundary sliding, which is decreased from 54% in the binary brass to 17-23% in the alloyed brasses, and to an increase in the contribution of the intragranular deformation from 10 to 30%. Experiments based on the Kirkendall method have shown that alloying leads to a slowdown of the diffusion processes, which can presumably limit the grain boundary sliding in the investigated multicomponent brasses.