Temperature effect on formation of reorientation bands in α-Ti

The temperature dependence of the critical deformation epsilon(cr) initiating dislocation reorientation bands (RBs) in alpha-Ti polycrystals of commercial purity is obtained by the method of statistical processing of TEM (transmission electron microscopy) images. A dependence of the specific volume beta occupied by the RBs in the polycrystal upon the strain epsilon and the temperature (4.2-393 K) is found. The effects observed are attributed to a decrease in the relative mobility of screw dislocations (as compared with edge dislocations) upon lowering the temperature,the thermally activated nature of dislocation rearrangements in the process of RB formation and the character of the temperature dependence of the critical shear stresses of slip and twinning. (C) 1998 Elsevier Science S.A. All rights reserved.