Mg alloy seamless tubes (MASTs) were prepared through three-high rotary piercing process, effect of billet temperature, feed angle and plug advance on microstructure, texture and mechanical properties of tubes were investigated. The effect on the deformation mechanism and improving mechanical properties mechanism of this process for MASTs were studied. The results show that the grain size could be refined to 11.3–31.1% of the initial grain size and the microstructure was more uniform due to the accumulation of strain. The formation of high strain gradient at the grain boundary activated the non-basal slip. This piercing process could change the grain orientation of as-extruded billet and eliminate the initial basal texture to produce new favorable texture. And the process could accelerate the continuous dynamic recrystallization process. After piercing, yield strength of pierced tubes decreased by 6.7%, ultimate tensile strength (UTS) and elongation increased by 32.4 and 45%, respectively, at optimal parameters. The plate-shaped β₁-Mg₁₇Al₁₂ orientation transformed from basal plates to prismatic plates, facilitating the increase in UTS and ductility. The decrease size of nanoscale precipitates could reduce the cracking possibility. The critical resolved shear stress ratios of pyramidal (10−11) slip and (11−22) slip to basal slip for the sample including prismatic plates both decreased compared to that including basal plates. This could enhance the ductility of tube sample. Moreover, grain boundary sliding could contribute to a better ductility via coordinating deformation and reducing stress concentration during piercing process.

采用三辊旋转穿孔工艺制备镁合金无缝管（MAST），研究了坯料温度、进给角和顶头进给量对管材显微组织、织构和力学性能的影响。研究了该工艺对MAST变形机制的影响和改善力学性能的机制。结果表明，由于应变的积累，晶粒尺寸可细化至初始晶粒尺寸的11.3%~31.1%，显微组织更加均匀。晶界处高应变梯度的形成激活了非基底滑移。这种穿孔过程可以改变挤压坯料的晶粒取向，消除最初的基础织构，产生新的有利织构。该过程可以加速连续动态再结晶过程。穿孔后，在最佳参数下，穿孔管的屈服强度下降了 6.7%，极限抗拉强度 (UTS) 和伸长率分别增加了 32.4% 和 45%。板状β ₁ -Mg ₁₇ Al ₁₂取向从基底板转变为棱柱板，有利于UTS和延展性的增加。纳米级析出物尺寸的减小可以降低开裂的可能性。对于包含棱柱板的样品，锥体（10−11）滑移和（11−22）滑移与基底滑移的临界解析剪切应力比均比包含基底板的样品有所减小。这可以增强管样品的延展性。此外，晶界滑动可以通过协调变形和减少穿孔过程中的应力集中来提高延展性。