<p>The microstructural characteristics, twinning behavior and deformation mechanism of the extruded ZK61 alloy were analyzed during shear deformation along the extrusion direction (ED), ED-45° and ED-90° with a strain rate of 3.6 × 10³ s⁻¹ at room temperature and 623 K, respectively. The results showed that an adiabatic shear band (ASB) composed of ultrafine grains with an average diameter &lt; 50 nm was formed. Moreover, the critical deformation region was composed of fine grains and numerous {10–12} tension twins, which could be attributed to the influence of the ASB. The ED sample presented more {10–12} tension twins at room temperature and 623 K, and the rise of deformation temperature suppressed the activation of the {10–12} tension twins. The texture analysis showed that the basal texture was weakened because of the activation of {10–12} tension twinning, especially in the ED sample. Another texture weakening effect could be attributed to the activation of the DRX process at high temperature. After evaluating the deformation mechanism, the basal slip was still the dominant deformation mechanism. More basal &lt;a&gt; slips and prismatic &lt;a&gt; slips were activated to coordinate the plastic deformation when the deformation temperature was increased, and the loading direction was not favorable for {10–12} tension twinning to occur in the ED-45° sample and ED-90° sample.</p>