Guangsheng Huang

Forming limit of textured AZ31B magnesium alloy sheet at different temperatures

Repeated unidirectional bending (RUB) was carried out to improve the texture of commercial AZ31B magnesium alloy sheets. All specimens were prepared in the rolling direction. The forming limit diagrams (FLDs) of AZ31B magnesium alloy sheet were determined experimentally by conducting stretch-forming tests at room temperature, 100, 200 and 300 °C. Compared with the as-received sheet, the lowest limited strain of AZ31B magnesium alloy sheet with tilted texture in the FLD increased by 79% at room temperature and 104% at 100 °C. The texture also affected the extension of the forming limit curves (FLC) in the FLD. However, the FLCs of two kinds of sheets almost overlapped at temperature above 200 °C. It can be concluded that the reduction of (0002) texture intensity is effective to the improvement of formability not only at room temperature but also at low-and-medium temperature. The effect of texture on FLDs becomes weak with increasing temperature.

Tensile properties and microstructure of AZ31B magnesium alloy sheet processed by repeated unidirectional bending

The mechanical properties of the AZ31B magnesium alloy sheet processed by repeated unidirectional bending (RUB) with a basal pole tilted in the rolling direction were systematically investigated at different temperatures. Compared with the as-received sheet exhibiting approximately the same average grain size, the fracture elongation increased while the proof stress decreased at room temperature. The initial texture had a significant influence on the mechanical properties at room temperature, while it showed a much weaker effect on the mechanical properties because of the activation of non-basal slips and initiation of dynamic recrystallization during deformation at elevated temperature.

Influence of Microstructure and Texture on Formability of AZ31B Magnesium Alloy Sheets

The effect of the repeated unidirectional bending (RUB) process and annealing on the formability of magnesium alloy sheets was investigated. The RUB process and annealing treatments produce two effects on microstructure: grain coarsening and weakening of the texture. The sheet that underwent RUB and was annealed at 300 °C exhibits the best formability owing to the reduction of the (0002) basal texture intensity, which results in low yield strength, large fracture elongation, small Lankford value (r-value) and large strain hardening exponent (n-value). Compared with the as-received sheet, the coarse-grain sheet produced by RUB and annealing at 400 °C exhibits lower tensile properties but higher formability. The phenomenon is because the deformation twin enhanced by grain coarsening can accommodate the strain of thickness.

Influence of strain rate on microstructure and formability of AZ31B magnesium alloy sheets

Abstract The effects of strain rate on microstructure and formability of AZ31B magnesium alloy sheets were investigated through uniaxial tensile tests and hemispherical punch tests with strain rates of 10−4, 10−3, 10−2, 10−1 s−1 at 200 °C. The results show that the volume fraction of dynamic recrystallization grains increases and the original grains are gradually replaced by recrystallization grains with the strain rate decreasing. A larger elongation and a smaller r-value are obtained at a lower strain rate, moreover the erichsen values become larger with the strain rate reducing, so the formability improves. This problem arises in part from the enhanced softening and the coordination of recrystallization grains during deformation.

Microstructure and formability evolutions of AZ31 magnesium alloy sheets undergoing continuous bending process

Abstract Continuous bending (CB) process along rolling direction was performed to improve the formability of AZ31 magnesium alloy sheets. The microstructure and texture evolutions were characterized by optical microscopy (OM) and electronic backscatter diffraction (EBSD). The results reveal that the basal texture intensity of continuously bent and annealed (CBA) sample is drastically weakened. A large number of twins are induced on the concave surface by the 1st pass bending and the density of twins obviously declines during the 2nd pass bending owing to the occurrence of detwinning. Due to the asymmetric tension–compression strain states between the outer and inner regions during V-bending, twinning and detwinning are generated alternatively during the CB process. The Erichsen value is 5.2 mm which increases by 41% compared with that of as-received sample. This obvious improvement of formability can be attributed to the weakened basal texture, which leads to a smaller plastic strain ratio (r-value) together with a larger strain-hardening exponent (n-value).

Influence of Grain Orientation on the Corrosion Behavior of Rolled AZ31 Magnesium Alloy

The effect of the grain orientation on corrosion behavior of rolled AZ31 magnesium alloy is investigated in this study. The test samples have a similar surface roughness to the Mg alloy in practical application. The immersion test and electrochemical impedance spectroscopy show that the TD–ND planes dominated by

Effects of grain size on shift of neutral layer of AZ31 magnesium alloy under warm condition

(10\bar{1}0)

Influence of different rolling routes on mechanical anisotropy and formability of commercially pure titanium sheet

(101¯0),