摩擦援用押出しを施したAZX612マグネシウム合金の機械的性質に及ぼす集合組織の影響

抄録

Since magnesium alloys are lightweight, they are expected to be promising as structural materials, particularly in transportation. However, because a strong basal texture is prone to develop parallel to the sheet plane in wrought products, formability at room temperature is poor. In this study, to control the basal texture of AZX612 magnesium alloy and to improve its formability, a lateral extrusion method, namely, friction-assisted extrusion (FAE), was applied, and the microstructure, texture, and mechanical properties were investigated. The FAE process was carried out with the extrusion ratios ranging from 4 to 20 at temperatures of 300 and 350 ℃. The results showed that FAE changes the basal texture of the starting as-rolled material into that inclined by about 15° against the extrusion direction and raises the intensity of texture. The 0.2 % proof stress became significantly smaller than that of the as-rolled material in the extrusion direction but larger in the transverse direction, resulting in the larger anisotropy. This can be understood by the activity of basal slip. Elongation to failure was smaller under all extrusion conditions than in the as-rolled material, which was presumed to be caused by the localization of shear deformation.