Hot compressive deformation behavior and electron backscattering diffraction analysis of Mg_95.50Zn_3.71Y_0.79 fine-grained alloy solidified under high pressure

An Mg_95.50Zn_3.71Y_0.79 fine-grained solidified alloy with a grain size of 16 μm was prepared by high-pressure solidification. The microstructure characteristics and hot compressive deformation behavior of the alloy solidified under high pressure were compared with the atmospheric-pressure solidified alloy by carrying out the unilateral compression tests under a strain rate in the range of 0.001–1.0 s⁻¹ and at a deformation temperature in the range of 523–573 K. The true stress-true strain curve of the high-pressure solidified alloy shows the typical dynamic recrystallization rheological curve. EBSD results show that when the deformation was carried out at 573 K, nearly 90% dynamic recrystallization occurred in the high-pressure solidified alloy, and the newly formed grains were distortionless and had low dislocation density. The high-pressure solidified alloy showed a double-peak basal texture at a strain rate of 1.0 s⁻¹. The two peak points showed a maximum pole density of 9.88 and 7.91, less than that in atmospheric-pressure alloy. When the deformation was carried out at the following conditions: deformation temperature = 573 K, strain rate = 0.001, and true strain = 0.9, the average Schmid factor (SF) for basal slip of the grains in the high-pressure solidified alloy was 0.419, and SF value for basal slip in 91% grains was greater than 0.3.