Dislocation behavior in a polycrystalline Mg-Y alloy using multi-scale characterization and VPSC simulation

•Dislocation behavior in a polycrystalline Mg-5Y alloy were quantitatively studied by in situ tensile test, visco-plastic self-consistent (VPSC) modeling, and TEM.•The critical resolved share stress (CRSS) values of basal , prismatic , pyramidal I , pyramidal I , and pyramidal II dislocation slip were measured.•The mobility of dislocations in Mg-Y alloy experimentally proved better than that in Mg-Ca alloy.•The reason behind the high ductility of Mg-Y alloys was clarified.