Microstructural features of rolled Mg-3Al-1Zn

Abstract

The microstructures of hot-and cold-rolled Mg-3Al-1Zn (AZ31) are examined using scanning electron and optical microscopy. It is shown that the microstructures following multipass hot rolling and annealing are more uniform than those formed by heavy single pass rolling and annealing. The importance of twins in producing intragranular recrystallization is evident, although the most dominant nucleation site is grain boundaries. The cold-rolled structure after a rolling reduction of 15 pct is dominated by the presence of deformation twins. Twin trace analysis suggests that approximately two thirds of the twins are a form of "c-axis compression" twin. A number of "c-axis tension" twins were also observed and additional in-situ scanning electron microscopy experiments were performed to confirm earlier observations that suggest these twins can form after deformation, during unloading.

Inverse strain rate sensitivity of bendability of an AZ31 sheet in three-point bending

“…One potential explanation is that the ductility of the annealed specimens is improved as the strain rate increases. But, available data in previous reports show that, in uniaxial tension, the ductility of Mg alloys presents a negative strain rate sensitivity [16][17][18]. The strain to failure in uniaxial compression behaves in a similar manner.…”

“…At a given temperature, their data suggests that the ductility decreases as strain rate increases. Maksoud et al [17] studied deformation of a Mg AZ31 alloy under tension at different strain rates and temperatures. They showed that the ductility of the material increases as the strain rate decreases.…”

“…Inside the twin bands, a high density of deformation twins was present; however, outside of the twin bands, twins were completely absent. Although the micro structure and mechanical properties of wrought Mg AZ31 have been extensively studied [17][18][19][20][21][22][23][24][25] over the past few decades, understanding of what occurs in the micro structure during bending and how the micro structure evolves require further investigation. Previous efforts have, in fact, focused on mechanical properties of AZ31 Mg alloys in uniaxial tension or compression [18][19][20][21][22][23][24][25] at various temperatures and strain rates.…”

Jnhmicro-texture of AZ31 Magnesium Alloy in Situ Tracking During Compressing Deformation

“…Deformation mechanism of AZ31 Magnesium alloy is slip and twinning [1]. The cylindrical sliding and compression twin is main mechanism in the process of deformation [2][3]. AZ31 Magnesium alloy sheet, which rolled at temperature 300 , presented large amounts of twin structure.…”

Extension twin variant selection during uniaxial compression of a magnesium alloy

“…Twinning in magnesium alloys plays an important role in plastic deformation during low and medium temperature mechanical forming operations [1][2][3][4][5][6] by providing additional independent deformation modes. The operation of twinning during deformation also has a strong effect on the flow stress and on texture evolution, as a result of the lattice re-orientation that accompanies twinning [7].…”