Plasticity and microstructure evolution of W-CeO₂ rods with different short-duration pulse currents

To improve the formability of W-rare earth electrode, the influence of high-energy pulse on the plasticity property of W-CeO₂ rods was investigated. The effects of current density (J ₀), pulse width (t _w), frequency (f), and strain rate on the plasticity of W-CeO₂ rods were discussed in detail. Results of tensile tests show that the W-CeO₂ rods applied with the electrical pulses obtain a maximum percentage total elongation at fracture (9.65 %), increased by 118.7 % compared to that without pulses. This is owing to both the heat effect and the interaction of current between dislocations and rare earth additions. Electron back scattered diffraction (EBSD)-generated grain boundary (GB) maps suggest that the length of low-angle grain boundaries composed of high-density dislocations decreases after deformation while applying the pulse current. This demonstrates that the short-duration pulsed current enhances the mobility of dislocations. Scanning electron microscopy (SEM) images of the rods after deformation with the pulse current show that the long fiber-shaped additions become discontinuous, which could reduce the stress concentration and hinder the crack propagation.