The present route to grain boundary engineering was usually based upon multiple annealing twinning which could only be applied to a certain subset of materials, namely those that twin prolifically. A more general approach was highlighted recently, following experimental evidence that certain boundary planes in iron bicrystals were ‘special’, and that this classification was not based upon misorientation. It was suggested that, under suitable conditions, individual interfaces could reorient the most energetically advantageous orientations. This approach agreed with a similar concept of ‘grain boundary plane engineering’, proposed previously. This concept was explored here and the effect of long duration, low-temperature annealing upon the distribution of boundary misorientation and planes in copper were reported. The new findings supported the possibility of grain boundary structure optimisation via controlled annealing. To have established that grain boundary plane reorientation was feasible opened up new possibilities.

Grain Boundary Reorientation in Copper. V.Randle, Y.Hu, M.Coleman: Journal of Materials Science, 2008, 43[11], 3782-91