Effect Of Electric Current Densities On The Microstructure Evolution And Mechanical Properties Of A Cu-Zn Dual Phase Alloy

As a typical modification technology for new materials,electric current pulses(ECP)import instantaneous high energy to atoms of material by influencing electron motion,thus it makes structure of material and the process of phase transformation changed,meanwhile it has a significant impact on the microstructure and mechanical property of materials.Based on the experimental results,the effect of electric current pulses on the microstructure and mechanical property evolution was investigated by changing the electric current density in a Cu-Zn dual phase alloy sheets.To character the microstructural evolution,XRD and SEM-EBSD were used.To further study the effect of ECP on microstructural evolution,the different electric current densities were used.To study the effect of ECP on recrystallization,the 12.35kA/mm2,12.50kA/mm2,12.70kA/mm2 and 12.99kA/mm2 were applied to the materials.With the increase of the current density,the content of fine recrystallized grains of a phase rose,tensile strength of sample decreased while the elongation of samples increased.When current density up to 12.70kA/mm2,recrystallized grains of a phase grow in local area,tensile strength and elongation of sample cut down.As the current density continued to increase,growing grains were homogeneous while deformed grains were also even in the case,tensile strength and elongation of sample had the increasing tendency.It also showed that ECP mainly influenced the recrystallization of a phase,including the size and distribution of recrystallized grains,but ECP had little impact on ? phase.In order to explore the effect of ECP on recrystallization nucleation rate of dual phase alloy,compare ECP treatment to annealing treatment,ECP treatment greatly accelerated the nucleation rate of recrystallization.To study the effect of ECP on phase transformation,the 13.26kA/mm2,13.50kA/mm2 and 13.90kA/mm2 were applied to the materials.With the increase of current pulses,high-temperature non-equilibrium ? phase were reserved at room temperature.Large amounts of fine ? phase grains were homogenous among a phase grains,this microstructure had the best mechanical property among three samples.The current density was 13.90kA/mm2,product ? phase grains had already grown up,meanwhile fine product a phase could be found in big original ? phase because of phase transformation.Also finding original a phase broke.These lead the strength of material increased slightly,but lower plasticity.