Impact Factor:6.6

DOI number:10.1016/j.jmrt.2025.07.242

Affiliation of Author(s):Hefei University of Technology

Journal:Journal of Materials Research and Technology

Key Words:titanium alloy; electrically-assisted forming; strain rate jump tensile test; strain rate sensitivity; rate-controlling mechanism

Abstract:Electrically-assisted strain rate jump (EASRJ) tension and EA quasi-static tension under different electro-thermo-mechanical routes were conducted to investigate the strain rate sensitivity (SRS) related macro-micro features and electroplastic mechanisms of TC4 alloy sheet. Results reveal that yield stress and ultimate tensile stress decrease monotonically and flow softening as well as E-typed Portevin Le-Chatelier bands become notable with increasing current density at 0.0005 s-1. While the elongation first decreases, then increases and surpasses the current-free level and finally decreases with current density under the combined effect of electroplasticity and local Joule heating induced premature failure. Dynamic strain aging (DSA), electrically-induced dynamic recrystallization (DRX), slight α→β phase transformation and grain boundary deformation coordination under “hot spots” and charge imbalance effects are the featured microstructure evolution phenomena in quasi-static EA tension. According to the EASRJ tension results, SRS value is relatively low (0.01～0.02) in current-free case, it decreases to near zero at 10 A/mm2 and increases sharply to 0.25～0.40 at 20 A/mm2. Lower ultimate strain rate results in lower grain size, higher β phase content and recrystallization rate up to 12.7%, and thus slight divergence in SRS values at high current densities. The variation in deformation mechanisms and enhanced thermal activation effects synergistically cause this significantly increased SRS, and the controlled mechanisms with increasing current density are sequentially DSA, dislocation slip, intersection and rearrangement coordinated by mixed dynamic recrystallization (DRX) and grain boundary sliding (GBS).

First Author:Siliang Yan

Indexed by:Journal paper

Document Code:14603

Discipline:Engineering

Document Type:J

Volume:38

Issue:-

Page Number:474-489

Translation or Not:no

Date of Publication:2025-07-28

Included Journals:SCI、EI

Links to published journals:https://www.sciencedirect.com/science/article/pii/S2238785425019003?via%3Dihub

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