Work hardening and recovery in sapphire (α-Al2O3) undergoing prism plane deformation

Chromium hardening and Peierls mechanism for basal slip in sapphire (α-Al2O3) at temperatures between 900 and 1500°C

“…They are not significantly higher than for undoped sapphire. 2,7 For all Cr concentrations and temperatures, we did not observed any serrated flow that is typical of dynamic strain ageing due to mobile dislocations interacting with diffusing impurities.…”

“…(0 0 0 1)1/3 2 1 1 0 basal slip is the primary deformation system for temperatures above 700 • C. [1][2][3][4][5][6][7] Prism plane slip along {12 1 0} 1 0 1 0 is the easiest slip system below 700 • C. 3,4 The 1 0 1 0 Burgers vector for prism plane slip, which is the fourth in length in sapphire, is dissociated into three partial dislocations with collinear 1/3 1 0 1 0 Burgers vector. 8 The Peierls mechanism has been frequently invoked to explain the movement of dislocations in sapphire, as much in the basal plane as in the prismatic plane, at intermediate temperatures.…”

Structure and Configuration of Boundary Dislocations on Low Angle Tilt Grain Boundaries in Alumina

“…In the case of slip dislocation, it is known that the prism plane dislocation can dissociate into the three partial dislocations as shown here. 24,26) So far, however, it does not seem that the structure of prism plane dislocations array that compose a low angle tilt grain boundary is observed by transmission electron microscopy.…”

“…[27][28][29]31) In the case of low angle tilt grain boundaries with the f1 2 210g boundary plane, the structure can be estimated using the equations. On the other hand, it seems that the stacking faults off the f1 2 210g plane have not been studied enough, although the stacking faults along f10 1 10g were investigated by experimentals with conventional transmission electron microscopy 24,26,28) and theoretical calculations. 29,31) Accordingly, it can be said that the actual structures of the stacking faults off the f1 2 210g plane leaves a lot of unclear points.…”

Effects of processing conditions and ambient environment on the microstructure and fracture strength of copper/niobium/copper interlayer joints for alumina

“…More likely, diffusion bonding is assisted by plastic deformation. Creep of both aluminum oxide [98] and niobium occur at ≈1700°C during diffusion bonding [74,91] . Interface migration and reprecipitation may be beneficial for eliminating very small voids; however, the extent of this effect will decrease as lower bonding temperatures are used.…”