Prof. Yuanshen Qi
14/01/2026
Zoom \ GTIT: Room – NC R202
Israel - 12:30 \ GTIIT: 18:30 China time (Beijing Time)
Shock-type energy delivery has emerged as a transformative approach for manipulating materials far from thermodynamic equilibrium. While thermal and mechanical shock have been extensively studied, electrical shock through electric current pulse, i.e., electropulsing, represents a fundamentally distinct pathway that directly injects energy into the electronic subsystem of metals. Research on electropulsing dates to Troitskii’s pioneering work in the 1960s, which reported anomalous reductions in flow stress during zinc deformation under electric pulses. Despite decades of investigation, critical gaps remain: the quantitative relationship between EP parameters and microstructural outcomes is unresolved; the relative importance of proposed mechanisms (electron wind force, local Joule heating, and non-thermal effects, etc.) is elusive; and the dynamics of crystal lattice defects under extreme non-equilibrium conditions lack quantification.
In this seminar, I will present our recent advances addressing three fundamental questions in electropulsing. First, we establish quantitative thresholds between current density and microstructural transformation, demonstrating that phenomena such as precipitate dissolution occur abruptly above critical current density and energy density thresholds. Second, we propose and validate a supersaturated vacancy mechanism, showing how electropulsing generates transient vacancy concentrations exceeding equilibrium values by orders of magnitude to enable ultrafast phase transformation such as precipitate nucleation and growth. Third, we reveal how electropulsing fundamentally alters interface evolution pathways, enabling unprecedented control over grain boundary (GB) motion, GB partitioning and phase transformation. Beyond electropulsing, other studies we have been investigating will be briefly summarized, including the influence of iron doping on grain boundary mobility of alumina, solid state dewetting of nickel thin films and oxidation of nickel nanoparticles, and argon gas-filled nano-bubbles in severely deformed nickel.