The rate of twin layer growth in bismuth single crystals

The stress dependence of the normal and tangential rate of twinning is determined in bismuth single crystals of different purities. On the basis of experimental data it is concluded that the broadening of twin layers occurs by a heterogeneous mechanism. The activation volumes defining the processes of twin layer broadening and twin growth in the shear direction are determined. It is established that the process of twin layer broadening in bismuth involves the simultaneous reorientation of about 10 4 atomic planes and in each plane 10 to 10 2 twinning dislocations participate per centimetre length of twin plane in the shear direction.