Orientation Relationships Between Alpha Prime and Beta Phases in a Ti-Ni Alloy

Abstract

Summary 1) The activation energy for grain boundary slip in copper is considerably less than that for self- diffusion. Copper is, therefore, an exception to Ke's theory that the two activation- energies should be the same for all metals. 2) Adding solute elements to the copper sup- presses the internal friction peak due to grain boundary relaxation in copper, and causes a second solid solution peak to appear on the internal friction- temperature curve at a higher temperature. For some of the alloys containing a small percentage of solute atoms, both the copper peak and the solid solution peak appear together on the same curve; showing that the processes causing the peaks are independent, and that the alloying elements do not move the copper peak to a higher temperature. 3) The activation energies for grain boundary relaxation in the alloys are approximately the same for all the alloying elements used, 44,000 cal per mol, which compares with 33,000 cal per mol for grain boundary relaxation in copper. 4) The temperature of the solid solution peak decreases with increasing concentration of the solute element, and can be related to the solidus tempera- ture of the solid solution., 5) The results of the experiments on the solid solutions do not seem to be consistent with either of the mechanisms so far put forward. to explain grain boundary slip.