MODELING THE TRANSFORMATION TEXTURE OF TI-64 SHEETS AFTER ROLLING IN THE BETA-FIELD

The variant selection occurring in the beta-alpha phase transformation of Ti-64 material after rolling in the beta-field was investigated by using texture transformation modelings. In a previous work published in this journal, we observed that the variant selection was very sensi tive to the deformation degree imposed at high temperature prior to th e transformation. In this contribution, we assumed that crystal defect s formed during glides on the {110}[111] and {112}[111] beta Slip syst ems could favor the growth of plates corresponding to specific variant s. Moreover, a detailed study of the beta --> alpha phase transformati on suggested a link between the selected variants and the slip systems activated at high temperature. Therefore, we developed a texture tran sformation modeling, assuming that a variant is selected if its corres ponding slip system was sufficiently activated in the last step of the hot deformation. The activity of the slip systems was evaluated by a rate sensitive Taylor model. The modeling was applied to a Ti-64 mater ial 75% rolled at 1050 degrees C and the simulated texture was in good agreement with the experimental one. (C) 1997 Elsevier Science S.A.