The effect of temperature and the deformation mode on the properties of ZnGa 0.2 at% single crystals

ZnGa0.2 at.% single crystals, prestrained in the systems (0001) <11 (2) ove r bar 0> and {11 (2) over bar 2} <1 (1) over bar 23>, and next subjected to deformation in the system (0001) <11 (2) over bar 0> at the strain rates ( epsilon) over dot = 7 x 10(-4) s(-1) and (epsilon) over dot(2) = 7 x 10(-3) s(-1), were investigated in a compression test at the temperatures 77, 295 and 473 K. Not - prestrained single crystals were examined for the purpose of comparison. It has been found that in both examined systems prestraining causes an incr ease of shear stresses in the system (0001) <11 (2) over bar 0> at the temp eratures 77 K and 295 K, and a decrease at the temperature 473 K at prestra ining in the basal system. A complex character of the influence of temperat ure and of the change in the deformation path on the strain rate sensitivit y and the activated volume has been observed. Structural observations have revealed that the boundaries of subgrains affect the process of strain hard ening and the formation of shear bands.