TEXTURE DEVELOPMENT DURING THE TORSION TESTING OF ALPHA-IRON AND 2 IFSTEELS

The textures of two interstitial Free (IF) steels and a high purity al pha-iron were determined after deformation in torsion over the tempera ture range 20-500 degrees C. The three characteristic b.c.c. torsion f ibres are described in detail and the locations of some important idea l orientations are identified on the {110} pole figure. At room temper ature, these are the F (110) [001], J1 (0 (1) over bar 1) [(2) over ba r 11], J2 (1 (1) over bar 0) [<(11)over bar>2], D1 (11 (2) over bar) [ 111], D2 (<(11)over bar>2) [111], E1 (01 (1) over bar) [111] and E2 (0 (1) over bar 1) [111]. The D1, D2 and F dominate, while the E1 and E2 appear at slightly lower intensities at 400 and 500 degrees C. Textur e simulations were carried out using the rate sensitive theory of crys tal plasticity. These called for lengthening to take place, in agreeme nt with the measured length changes. The simulated and experimentally observed 'tilt' phenomena are similar to those commonly reported in th e literature for f.c.c. materials. The explanation For this phenomenon developed for the latter materials is extended to b.c.c, metals. The development of torsion textures is discussed in terms of the rotation rate vector R over dot, the divergence-convegence properties of orient ation flow and the stability parameter S. Copyright (C) 1996 Acta Meta llurgica Inc.