Effects of Current Density on Elongation of an Electropulsing Treated Zn-Al Based Alloy

Abstract

Effects of static electropulsing on microstructure and elongation of the ZA 22 alloy were studied by using scanning electron microscopy and transmission electron microscopy techniques. It was found that the current density of electropulsing treatment (EPT) was one of the factors that influenced microstructural changes and dislocation structure in the EPT alloy. The identity of the microstructure and the dislocation density played an important role in plastic elongation of the EPT alloy. The effects of the current density of electropulsing on elongation of the alloy were discussed from the point of view of microstructural evolution and dislocation dynamics.

Electropulsing Induced Texture Evolution in the Recrystallization of Fe-3 Pct Si Alloy Strip

“…A large number of dislocations piled up and blocked at the grain boundaries and at the structural defects, such as dislocations, vacancies, and precipitates, inside the grains, where a great deal of strain energy accumulated. [5][6][7] The energy storage at the grain boundaries and the structure-distorted sites inside the grains varied in accordance with the dislocation movement mechanism. At the grain boundaries, accumulation and annihilation of dislocations occurred at the same time.…”

“…When the intensity of the electropulsing increased to 152 Hz/1023 K (750°C)-EPT, a new balance between the accumulation and the annihilation of the dislocations was established. [6] Both the texture (100)h110i (green in color) and the higher energy stored (111)h112i texture (dark blue in color) vanished. The textures consisted of mainly (111)h110i (color in light blue) and a small amount of G (110)h100i, as shown in EBSD mapping (Figure 4(a3)).…”

“…[1,2] As a new developing process, electropulsing was found to be more powerful than the thermal energy in improving microstructure and the properties of the alloys, and in strengthening the metallurgical processes. [5][6][7][8][9] Electropulsing treatment (EPT) was applied to obtain well-recrystallized grains and to retard the formation of annealing twins in the cold-worked alloys. [5,[10][11][12] However, few studies about the effect of electropulsing on recrystallization of Fe-3 pct Si alloy strip have been reported.…”

Effect of Static Electropulsing on Microstructure and Elongation of a Zn-Al Alloy (ZA22)

“…The wire specimen was cut into pieces of 100-mm length for static EPT (without external stress affect) at ambient temperature (28°C). A self-made electropulsing generator was applied to discharge positive direction multiple pulses with various current intensities (10,15,20, and 30) for 10 seconds. The frequency of the multiple electropulses was selected as 100 Hz.…”

“…[9][10][11][12][13][14][15][16] Previous work by the present authors and co-workers has shown that electropulsing induced phase transformations consisted of two kinds of phase transformations: forward and reverse phase transformations. [6] It was also reported that with adequate dynamic electropulsing, the elongation of the Zn-Al based alloy was increased by 437 pct at ambient temperature under a high strain rate, whereas the instantaneous tensile stress remained unchanged, compared with that of the non-EPT alloy.…”