Transition from GBS to Dislocation Creep in SKY5083 Material

Contributed by Terry McNelley of Naval Post Graduate School

Transition to GBS from Dislocation Creep in a SKY5083 Material

The EDAX TEAM™ EBSD Analysis System shows the transition from grain boundary sliding to dislocation creep in SKY5083 sheet material

Mechanical property data for a superplastic SKY5083 sheet material are shown at the upper left as a plot of diffusion-compensated strain rate versus modulus-compensated stress.

Samples were deformed in tension along the rolling direction (RD) for the sheet. The data (symbols) are consistent with independent contributions to the deformation from grain boundary sliding (GBS) and dislocation creep. Two samples deformed in the GBS regime (wherein the stress exponent, n, has a value of 2) exhibit dynamic grain growth and a random texture, as indicated by the discrete pole figures and grain maps in the lower two insets. The grain maps are plotted by superposition of continuous image quality and random color.

Samples deformed in the dislocation creep regime (n = 5) show development of a two-component fiber texture consisting of grains having either a <100> or a <111> aligned with the tensile axis. The discrete pole figures and grain maps are shown in the two insets at the right.

Reference:
M.T. Pérez-Prado, G. González-Doncel, O.A. Ruano and T.R. McNelley. Texture Analysis of the Transition from Slip to Grain Boundary Sliding in a Discontinuously Recrystallized Aluminum Alloy, Acta Mater., 49, (2001) 2259-68