Microstructural and processing factors influencing the formation of annealing twins

Quantitative understanding of the process and thermodynamic parameters involved in the formation of annealing twins after plastic straining, is important in being able to control the manufacturing process of twin generation on a commercial scale. In the present paper modifications are made to the only two existing publications in the literature that treat twin formation in a quantitative manner. Both the equations of Pande et al. and an earlier one by Gleiter, are modified to account for strain and then compared with results from the literature and data generated by the present authors on commercially pure nickel. Good agreement is made between the theoretical predictions of the two models suitably modified for strain values from 3.0 to 7.5%. It was also noted that there is a synergistic effect of strain and temperature in influencing the density of annealing twins. Optimization of both parameters results in the density of annealing twins in commercially pure nickel reaching a value of 2.3 x 10(4) m(-1). (C) 2009 Elsevier B.V. All rights reserved.