Li, X., Huang, C., Yang, J., Liu, F., Wei, S., Wan, M., Zhao, F., & Zhao, Y. (2024). Optimization of quasi-β forging parameters to control trimodal microstructure parameters and performance of TC21 forgings. Materials Science and Engineering: A, 909, 146824. https://doi.org/10.1016/j.msea.2024.146824
Abstract:
This study aims to explore the influence of distinct forging parameters on
microstructure and mechanical properties of TC21 forgings. The trimodal
microstructure, which includes equiaxial α (αeq), lath α (αlath), and fine α (αfine) phases,
was achieved via quasi-β forging and dual heat treatment. Subsequently, mechanical
properties were evaluated through tensile, impact toughness (ak), and fracture
toughness (KIC) tests. Results indicate that the content of αeq is higher at lower forging
heating temperature, whereas the content of αlath is diminished and the size of αfine
remains relatively small. This tendency reverses at higher forging heating temperature
due to the increased driving force of the phase transition. The rise in αlath content
implies more pronounced interface strengthening and plastic deformation, which
significantly contributes to strength compared to αfine and αeq but exerts a weaker
influence on plasticity. Moreover, the combined deformation and fracture of αlath and
αfine exert a significant influence on the initiation and propagation of cracks in ak and
KIC specimens. The limited coordination of deformations exhibited by αlath leads to
preferential stacking dislocations and shear fractures at interfaces, which are further
influenced by its higher aspect ratio affecting crack propagation paths. This not only
increases the required energy for initiating cracks but also raises energy consumption
during their propagation. Crucially, the presence of αfine significantly enhances the
dislocation accumulation and the plastic deformation zone at the crack tip, thereby
playing a pivotal role in determining local deformation capacity and crack deflection
frequency.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This work was supported by the National Natural Science Foundation of China (Nos. 52061005 and 52261025), the Science and Technology Program of Guizhou Province (Nos. YQK[2023]009, [2021]310, and [2023]278).