Speaker
Description
A novel “electric current pre-treatment + corrugated–flat rolling” (E-CFR) process was developed to fabricate high-strength and high-ductility Ta-12W refractory alloy, effectively suppressing macroscopic delamination during plastic deformation and achieving a superior strength–ductility synergy. The process involves two rolling passes: corrugated rolling in the first pass to introduce a wavy sheet structure, followed by flat rolling in the second pass with a reduction ratio of 40%. Prior to each pass, pulsed electric current heating was applied, maintaining the rolling temperature at 300 °C. Corrugated rolling disrupts the conventional plane-strain compression state and introduces a periodic strain gradient, while the subsequent flat rolling exhibits a pronounced stress–strain inheritance effect, resulting in a spatially heterogeneous stress state. This multi-axial stress condition activates additional slip systems, promotes grain rotation, and diversifies grain orientations and texture components, thereby suppressing the formation of sharp textures. Simultaneously, the periodic strain gradient transforms coincidence site lattice boundaries from banded to dispersed distributions, enhancing resistance to crack propagation. The Joule heating effect replaces conventional heating, enabling warm rolling at 300 °C and significantly reducing flow stress. Moreover, the electroplastic effect facilitates dislocation disentanglement and alleviates local stress concentration, ensuring stable deformation. After annealing, the microstructure becomes more homogeneous. The processed Ta-12W alloy exhibits an ultimate tensile strength of 969 MPa and an elongation of 34%, demonstrating excellent mechanical performance. This study provides an effective strategy for the advanced processing and high-performance fabrication of tantalum–tungsten alloys.
| Speaker Company/University | Taiyuan University of Technology |
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