Formation of nanophases in a Cu–Zn alloy under high current density electropulsing

Abstract

The microstructure of samples before and after a high current density electropulsing treatment was characterized by using high-resolution transmission electron microscopy. It has been found that in the coarse-grained Cu–Zn alloy subjected to the electropulsing treatment, two nanophases were formed, α–Cu(Zn) and β′–(CuZn), the average grain size of which is about 11 nm. A possible mechanism for the formation of nanophases was proposed. The experimental results indicated that electropulsing, as an instantaneous high-energy input, plays an important role in the nonequilibrium microstructural changes in materials and serves as a potential processing approach to synthesize nanostructured materials.

Formation of Nanotwins in Cold-Rolled Cu-Zn Alloy by Electric Current Pulses

“…In fact, Zhang et al observed that in the coarse-grained Cu-Zn alloy subjected to the ECP treatment, a nanophase of about 11 nm was formed. 17) In our previous study, 8) the diffusivity of the Pb inclusions in a Cu-Zn alloy was significantly enhanced due to the ECP application. Based on the above theoretical analysis and the corresponding experimental results, it is reasonably deduced that diffusive phase transformation is induced in the ECP heating treatment.…”

Effect of Electric Current on the Inclusions in a Cu-Zn Alloy

“…17) In fact, Horvath et al have found that the self-diffusion coefficient in nanocrystalline Cu about 10 nm is as three orders of magnitude large as coarse-grained Cu, 21) while its diffusion activation energy is comparable with that in surface of Cu. Recently, Zhang et al have observed that in the coarsegrained Cu-Zn alloy subjected to the ECP treatment, 5) the nanophase about 11 nm was formed. Hence, the transfer of coarse lead inclusions into grain boundaries or defects in dispersed small particles is ascribed to the directional electromigration and also the isotropic diffusion of lead.…”

“…Recently, studies concerning grain refinement in conventional coarse-grained materials by applying high current density ECP treatment have achieved lots of significant results. [4][5][6] For example, Zhou et al have found that grains in a low carbon steel are refined after high current density ECP treatment; 4) Zhang et al have found that nanophases are formed in a conventional coarse-grained polycrystalline Cu-Zn alloy by applying high current density ECP treatment.…”

Effect of electropulsing treatment on solid solution behavior of an aged Mg alloy AZ61 strip

“…In the case of EPT, the recrystallization mechanism could be attributed to the coupled action of thermal and athermal effects. 11 Zhang et al 12,13 developed an electropulsing treatment for synthesizing nanostructured materials directly from conventional coarse-grained crystalline materials because of the rapid heating/cooling cycle resulting from electropulsing. However, the method of EPT applied to the solid solution treatment of magnesium alloys on-line has not been reported.…”