The Influence of Bending Temperature on the Bending Formability and Microstructure of Mg‐2Zn‐Based Alloy Thin‐Walled Tubes

Strong basal textures in magnesium alloy tubes impair their secondary formability. This study developed Mg‐2Zn‐0.4Ce‐0.4Mn‐0.2Ca (ZMEX, 2#) thin‐walled magnesium alloy tubes with both low cost and weak texture through micro‐alloying with Ce and Ca. Mg‐2Zn‐0.4Ce‐0.4Mn (ZME, 1#) tubes serve as the control group. The microstructure and bendability of both tubes are investigated at different bending temperatures. Results indicate that cracking occurred on the upper walls of both alloys during room temperature bending, though the severity is lower in the 2# tube than in the 1# tube. As bending temperature increases, cracking disappears in both alloys. Their peak load displacement (PLD) and maximum bending displacement (MBD) values gradually rise, while total energy absorption (TEA) shows an initial increase followed by a decrease. Compared to the 1# tube, the 2# tube demonstrates superior bending formability, particularly at 200 °C (PLD, 14.5 ± 0.5 mm; MBD, 45.0 ± 3.3 mm; TEA, 142.9 ± 1.7 J). Electron backscattered diffraction analysis reveals that the enhanced bending performance of the 2# tube primarily stem from weak texture promoting slip activity, refined grain size, and Zn/Ca elemental segregation at grain boundaries. This study provides a theoretical basis for developing magnesium alloy tubes with good secondary formability.