La₂O₃添加Mo板における長大結晶粒積層組織の形成と機械的性質

抄録

Molybdenum sheets (trade name: TEM) having elongated coarse-grain structures were developed. The grain structures were controlled by hot and cold rolling under high total reduction ratio (ε_t) and recrystallization treatment at 2070K of sintered Mo body with lmass% of La₂O₃.
The recrystallization temperatures of La₂O₃-doped Mo sheets which were examined in terms of Vickers hardness and optical microstructure were higher than those of pure-Mo and TZM (Mo-0.56Ti-0.086Zr-0.016C by mass%) sheets. In particular, that of the La₂O₃-doped Mo sheet with high ε_t of 99.1 % was about 1830K, 400K higher than that of the pure-Mo sheet.
The deformation resistance of TEM sheets having elongated coarse-grain structures, which was examined by sag tests at 1470K to 2070K, were superior to those of the pure-Mo and TZM sheets with equiaxial grains. In particular, deformation resistance was improved at aspect ratios (L/W) exceeding 20. Sag value of TEM sheets with L/W=150 after sag test for 36ks at 2070K was less than 1/100 that of pure-Mo sheet and less than 1/60 of TZM sheet.
The shock resistance of TEM sheets with L/W=150 at room temperature, which was examined by the falling-weight impact test, was superior to that of the pure-Mo sheet with equiaxial grains.