Study on the low mechanical anisotropy of extruded Mg-Zn-Mn-Ce-Ca alloy tube in the compression process

Abstract

In this study, the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED, 45ED and TD was prepared. The effect of the second phases, initial texture and deformation behavior on this low mechanical anisotropy was investigated. The results revealed that the alloy tube contains the high content (Mg1-xZnx)11Ce phase and the low content of Mg12Ce phase. These second phases are respectively incoherent and coherent with the Mg matrix, and their influence can be ignored. Additionally, the alloy tube exhibited a weak basal fiber texture, where the c-axis was aligned along the 0° ∼ 30° tilt from TD to ED. Such a texture made the initial deformation (at 1.0% ∼ 1.6% strain) of the three samples controlled by comparable basal 〈a〉 slip. As deformation progressed (1.6∼9.0% strain), larger amounts of ETWs nucleated and gradually approached saturation in the three samples, re-orienting the c-axis to a 0°∼±30° deviation with respect to the loading directions. Meanwhile, the prismatic 〈a〉 and pyramidal <c+a> slips replaced the dominant deformation progressively until fracture. Eventually, the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates, resulting in the low compressive anisotropy of the alloy tube.