高純度マグネシウムの室温塑性変形 Plastic deformation of high purity magnesium at room temperature
It is generally believed that formability of magnesium at room temperature is poor, owing to its crystal structure, hcp. However, in the case of high purity magnesium, cold-rolling at room temperature is easily carried out with higher rolling reductions. In the present study, high purity magnesium specimens with about 1 mm in thickness were prepared by a vapor deposition technique, which intrinsically possesses a purification process during evaporation and deposition. Cold-rolling with about 80% reduction can be applied to the specimen by a multi pass rolling without any cracking, except a small ear cracks. Moreover, it has been found out that recrystallization was induced by cold-rolling when the reduction rate was larger than about 30%. The (0001) texture was formed by cold-rolling, which did not deteriorate the formability. Non-basal dislocations were frequently observed in the cold-rolled specimens. Critical resolved shear stress for the non basal slip system is considerably lower in the high purity magnesium compared with those in the conventional magnesium and its alloys, which results in cross slip and annihilation of dislocations and causes the recrystallization.
軽金属 56(12), 711-715, 2006-12-30
The Japan Institute of Light Metals