Grain Boundary Sliding of Al-Cu Solid Solution Alloy Deformed by Shear

The behavior of grain boundary during the deformation by shear at a constant load and temperature was studied by the use of bicrystal specimens of Al-0.2∼0.5%Cu alloy. The alloy used is a solid solution at the test temperatures. The bicrystal specimens with the boundary misorientation angle of 33°06′∼34°16′ have been prepared by Bridgemann method. The experimental results are summarized as follows. (1) The addition of 0.2%Cu greatly affected the grain boundary sliding of pure Al, but the addition of 0.2∼0.5% Cu did not. (2) Grain boundary sliding versus time curves showed a tendency to show wavy variation after a linear change in the first stage, and this tendency was weakened with increase of the Cu content. (3) The contribution of grain boundary sliding to the deformation amount of the specimen became smaller with increase of the solute atom, and its maximum value of Al-0.2%Cu alloy was found to be about 16% at 400°C for 100 minutes. (4) A plot of the logarithm of the amount of grain boundary sliding per second versus the reciprocal of absolute temperature resulted in a series of straight lines. The activation energy for grain boundary sliding was calculated from the slope of those lines.