High-temperature tensile behavior of AZ61 magnesium plate prepared by multi-pass friction stir processing

Multi-pass friction stir processing (M-FSP) was used to produce large-scale AZ61 Mg plate with fine-grained structures. High-temperature tensile behavior of the M-FSP plate was investigated along different directions in a temperature range of 473–673 K at a strain rate of 1 × 10−2 s−1∼3 × 10−5 s−1, respectively. Microstructural evolution and texture change during high-temperature deformation were studied. The fine-grained plate with an average grain size of 7.8 ± 6.4 μm has been attained via M-FSP, while the microstructure is not homogeneous. The M-FSP plate is observed to exhibit tensile anisotropy at elevated temperatures. The highest elongation is obtained along the processing direction, with the maximum value of 211% achieved at 623 K and 3.3 × 10−4 s−1 due to the lower intensity of texture and higher value of Schmid factor with respect to this direction. Effects of grain structure inhomogeneity and texture on the high-temperature tensile behavior of the M-FSP plate are discussed.