Second Phase and Texture of Spray-Deposited Magnesium Alloy Containing Nd with Different Rolling Directions

The billets of Mg-9Al-3Zn-1Mn-6Ca-2Nd alloy produced by spraying deposition method (the Osprey process) were studied by scanning electron microscopy (SEM) and X-ray diffractometer (XRD) in order to analyze the effect of rolling (T=350 ℃ and pass reduction ε=25% and 35%) on microstructure and texture of pre-extruded magnesium alloy. The results showed that the size-asymmetry Mg alloy had not only Mg matrix and (Ca, Nd)Al2 (block-like and granule-like C15 phase) phase distributing along the rolling direction of 90° and 0° at 350 ℃, but also Mg0.97Zn0.03 phase after rolling deformation in the rolling direction of 0°. The granule-like C15 particles was prominently increased respectively after rolling along the rolling direction of 90° and 0° with the increase of pass reduction (ε=25% and 35%). And both block-like C15 particles and granule-like C15 particles had agglomeration phenomenon after rolling deformation in the rolling direction of 90°. Fine dispersed C15 particles impeding dislocation movement and then forming dislocation tangles promoting the diffusion of Zn, which was important for retaining Mg0.97Zn0.03 phase along the rolling direction of 0°. The size-asymmetry Mg alloy formed weak basal texture (0002) rolled along the rolling direction of 90° and 0° at 350 ℃, and the texture pole density levels of prismatic texture {1120} <1010> and pyramidal texture {1012} increased gradually after rolling deformation in the rolling direction of 0° with the increase of pass reduction (ε=25% and 35%), namely, texture randomization was achieved in Mg alloy. The change of Schmid factor of the basal slip system was the key to affecting texture randomization of the size-asymmetry Mg alloy. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.