Twins and grain boundaries-dominated the reverse Bauschinger effect and tension-compression asymmetry

Molecular Dynamics Simulation of Bauschinger Effect in Cu Nanowire with Different Crystallographic Orientation

“…This sudden change in the voltage value is known as the nucleation of dislocations within the nanowire system [7,49,50]. Partial dislocations dominated by Shockley partial dislocations slide rapidly along the {111} crystal plane, causing a sharp drop in stress [51]. It can be said that the greatest stress variation occurs in the <111> nanowire and this crystallographic orientation is the optimal arrangement of atoms in the nanowire for nucleation, growth and movement of dislocations.…”

“…If both tension and compression yield stresses are equal, the material behaves isotropically. To compare the difference in strength under tension and compressive loads, the tension-compression asymmetry (σy -σr) / σy formula was used [51]. The tension-compression yield strength and calculated tension-compression asymmetry for Cu nanowires with 1.…”

“…Tensioncompression asymmetry is usually caused by different microscopic mechanisms. However, the different tensioncompression asymmetries and BE exhibited by monocrystalline and polycrystalline materials await investigation [51].…”

“…From this, it can be said that the model nanowire structure exhibits reverse BE behavior where the compression yield strength is higher than the tension yield strength. The twin structures formed under compression deformation inhibit the movement of dislocations, causing the compression yield strenght to be slightly greater than the tension yield strenght, resulting in inverse BE [51]. However, it can be said from the increase in BP value that the increase in pre-strain increases the effect of BE.…”

Attenuation of the Bauschinger effect and enhancement of tension–compression asymmetry in single crystal aluminum by temperature

“…[26][27][28] The reason for the tension-compression asymmetry is the difference in the microscopic deformation mechanism, and the Bauschinger effect is due to the introduction of forwarding loading pre-dislocations and residual stresses. 29 The temperature change may lead to a modication of the plastic deformation mechanism. Whether the sensitivity of dislocation slip and twinning to temperature is consistent, and whether the effect of temperature on pre-defects can change the microscopic evolution aer stress inversion remains to be further investigated.…”