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采用喷射沉积技术制备Mg-9Al-3Zn-1Mn-6Ca-2Nd合金沉积坯,对其进行挤压预变形和轧制变形(T=350℃、ε=25%和35%),利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)研究轧制变形对镁合金组织及织构的影响。结果表明:尺寸不对称的镁合金板材在350℃分别经过90°和0°方向轧制后,镁合金除了有Mg基体、(Ca,Nd)Al2(块状和颗粒状C15相)相外,在0°方向轧制后还存在Mg0.97Zn0.03相。随道次压下率(ε=25%和35%)增大,分别沿90°和0°方向轧制后颗粒状C15粒子会明显增多,但在90°方向轧制后块状、颗粒状C15粒子均发生“团聚现象”。0°方向轧制过程中细小弥散的C15粒子阻碍位错运动形成位错缠结区有利于Zn元素扩散,是0°方向轧制Mg0.97Zn0.03相保留的重要原因;随道次压下率增大,在0°方向变形后尺寸不对称的镁合金板材形成较弱(0002)基面织构的同时且柱面织构{112-0}<101-0>和锥面织构{101-2}强度也逐渐增强,即实现了镁合金形变织构的随机化,轧制过程中基面滑移Schmid因子变化是影响尺寸不对称镁合金形变织构随机化的主要原因。
The as-deposited Mg-9Al-3Zn-1Mn-6Ca-2Nd alloy was prepared by spray deposition and pre-deformation and rolling deformation (T = 350 ℃, ε = 25% and 35% (SEM) and X-ray diffraction (XRD) to study the effect of rolling deformation on microstructure and texture of magnesium alloy. The results show that the as-cast Mg alloy sheet has the same microstructure as Mg matrix and (Ca, Nd) Al2 (massive and granular C15 phase) after being rolled at 90 ° and 0 ° respectively at 350 ℃. There is also Mg0.97Zn0.03 phase after rolling in 0 ° direction. With the increase of pass reduction (ε = 25% and 35%), granular C15 particles increased obviously after rolling at 90 ° and 0 °, respectively. However, after rolled at 90 °, C15 particles are “reunion phenomenon.” The fine dispersed C15 particles in the direction of 0 ° hinder the movement of dislocation to form the dislocation entanglement zone, which is favorable for the diffusion of Zn element and is the important reason for the retained Mg0.97Zn0.03 phase in 0 ° direction. The rate of increase in the direction of 0 ° after the deformation of the asymmetric size magnesium alloy sheet to form a weaker (0002) basal texture and cylindrical texture {112-0} <101-0> and cone texture { 101-2}, which means that the random deformation of the deformed structure of the magnesium alloy is realized. The Schmid factor variation of the base slip during the rolling process is the main reason that influences the randomness of the deformed texture of the asymmetric magnesium alloy.