Effect of Temperature on Stretchability of Anisotropic AZ31 Magnesium Alloy Sheet

Abstract

This paper deals with effect of temperature on stretchability of anisotropic AZ31(Mg-3%Al-1%Zn) magnesium alloy sheet. Results of stretching process test are compared with those of tensile test. The sheet has an anisotropic character for angle to hotextrusion direction( =0°, 45°, and 90°). Here, =0° means a direction of extrusion. Tensile specimens cut down to three directions of =0°, 45°, and 90° are a shape of 14mm in elongation, 3mm in width and 0.44mm in thickness. Test piece for investigating the limiting stretching stroke is a sheet of side length 90mm and 0.44mm in thickness. For the stretching process test, the punch head is a hemispheric shape of 20mm in diameter and the die is a cylindrical shape of 27mm in inside diameter. Both tension and stretching process tests were performed at four kinds of test temperature(T=293, 393, 473, and 573K) in a thermostatic chamber and at a crosshead speed(v) of 5 mm/min using an Instron-type testing machine. Comparing the limiting stretching stroke determined by the stretching test with elongation, r-value, and n-value obtained by the tensile test, it is confirmed that the limiting stretching stroke is qualitatively related to the elongation and r-value, and not to n-value.

Influence of specimen size and sheet thickness on the material behavior of AZ31B under uniaxial tension

“…Considering the standard deviation, no significant difference exists, while miniaturized specimen in 45 ° to RD indicate a slightly higher anisotropic behavior than the reference tests. With a Lankford coefficient of 1.46 ± 0.04 in 0° to RD, the results of the miniaturized specimen are comparable to Fukuda et al [9] with a Lankford coefficient of 1.52 at an elevated temperature of 200 °C. Although, no significant differences of the miniaturization of the specimen on the evolution of the strain path (see figure 10) and the Lankford coefficients (see figure 11) are observable.…”

“…Due to an observed influence of strain hardening, which falsifies the obtained yield stress (see figure 1), no further milling operation is done in the measuring area of the examined specimen. Additionally, the results without the influence of strain hardening are rather comparable to literature values [9]. In order to qualify a miniaturized specimen geometry (Type B) for uniaxial tensile tests, a standardized specimen geometry (Type A) according to DIN 50125 is chosen as reference (see figure 2).…”

“…Regarding the estimated standard deviation, this influence is not significant. Comparing the Lankford coefficient in 0 ° to RD with results from literature [9], a smaller deviation in case of miniaturized specimen is identified compared to the results of the reference geometry. Additionally, no steady increase of the Lankford coefficient with higher angle to the rolling direction is ascertained for miniaturized tensile tests as well as for the reference tests with larger specimen.…”

“…Additionally, the results of both test setups illustrate that no significant influence of the anisotropy on the yield stress and the tensile strength exists at an elevated temperature of 200 °C. Fukuda et al [9] explained the material behavior at elevated temperature above 473 K (= 200 °C) by the activation of additional slip systems at elevated temperatures and dynamic recovery, which reduces the texture induced anisotropic behavior of the initial sheet metal.…”

Effect of Bonding Temperature on the Microstructure and Strength of the Joint between Magnesium AZ31 and Ti-6Al-4V Alloys Using Copper Coatings and Tin Interlayers

“…However for bond made at 600 C, the shear strength was depressed. The reduction of the strength for bond made at 600 C could be due to the effect of thermal softening of the magnesium alloy at high temperature which was reported in the literature [17][18][19]. Bond made at 580 C gave the maximum joint strength of 78 MPa.…”