• Zn addition significantly enhances dynamic recrystallization (DRX) in Mg–Gd–Sm–Zr alloys, promoting a transition from discontinuous to continuous DRX mechanisms.
• The presence of Zn reduces the {0001} basal texture strength and increases the Schmidt factor for non-basal slip, improving formability.
• A novel dynamic precipitation phase (Mg,Zn)3(Gd,Sm) forms in Zn-containing alloy, which inhibits grain boundary migration and dislocation motion, thereby refining recrystallized grains.
• The study provides constitutive equations and critical strain models that are essential for optimizing hot working processes of these magnesium alloys.