Advances in Titanium Technology: General Topic of Ti and Ti Alloys
Sponsored by: TMS Structural Materials Division, TMS: Titanium Committee
Program Organizers: Don Li, Howmet Engineered Products; Yufeng Zheng, University of North Texas; Peeyush Nandwana, Oak Ridge National Laboratory; Matthew Dunstan, US Army Research Laboratory
Thursday 2:00 PM
March 18, 2021
Room: RM 30
Location: TMS2021 Virtual
Session Chair: Peeyush Nandwana, Oak Ridge National Laboratory
2:00 PM
The Effect of Process Parameters on Abnormal Grain Growth during Beta Annealing of Hot-Forged Ti-6Al-4V: Nathan Levkulich1; Lee Semiatin2; Adam Pilchak2; Eric Payton2; 1Ues Inc.; 2Air Force Research Laboratory
Process variables contributing to the occurrence of non-uniform, abnormal grain growth (AGG) during annealing following subtransus, conventional hot forging of Ti-6Al-4V were determined. To this end, sidepress forging trials of cylindrical preforms with a preheat temperature of 1172 K, 1186K, or 1227 K and a diametral reduction between 40 and 70 pct were performed. Following hot working, slices were sectioned and beta annealed. The microstructure reconstructed from electron backscatter diffraction measurements of the corresponding α-phase texture revealed bands of course grains in the center of some of the slices. Finite-element simulations of the metal flow during sidepressing were coupled with viscoplastic-self-consistent modeling of texture formation to interpret the laboratory observations and thus explain the source of the coarse grains. These results indicated that forging temperature, forging reduction, preform diameter, subtransus heat treatment (prior to beta annealing), and preform starting texture may each influence the development of AGG.