大型TC4钛合金试样的退火处理模拟及变形机制研究

Aiming at the annealing deformation problem of typical TC4 titanium alloy specimen after milling, the effect of machining mode on the initial stress distribution of specimen surface was statistically analyzed and modeled. The influence of residual stress, cooling rate of heat treatment and structural length on heat treatment deformation were discussed based on the finite element model. The results indicate that for titanium alloy and aluminum alloy specimens, the residual stress caused by milling is dominated by compressive stress, and the stress distribution presents approximately "half S shape" with the increase of layer depth. Compared with the theoretical model that ignore the residual stress distribution caused by milling, the deformation degree of the model specimen that consider residual stress distribution has a tendency to increase with the increase of milling accuracy. With the increase of cooling rate, the deformation degree of titanium alloy specimen is increased and presents a parabolic trend. By applying constraints, the deformation degree of large-scale titanium alloy specimens with long and thin wall can be improved, and the heat treatment deformation of specimens is sensitive to the position of constraints.