| 摘要 |
PURPOSE:To measure the propagation velocity of a crack precisely in a high vacuum by mounting a specimen to the rod on the lower side of two-stage type bellows, to store the same in a vacuum chamber, and providing a pulse-like loading device on the upper side of the bellows. CONSTITUTION:A specimen 9 such as silicon crystal is mounted to the rod 10 on the lower stage side 121 of two stage type bellows 12 and is stored in a vacuum chamber 1. A loading device 20 is provided by means of a retaining plate 13 and a mounting plate 16 in the upper part of the bellow 12, and a lead wire which detects the propagation velocity of a crack is mounted to the specimen 9. The specimen 9 is set to the rod 10 and the inside of the chamber 1 is evacuated to a high degree of vacuum through an evacuation pipe 21. Electric current is flowed to a coil 18 so as to apply load like pulses and the propagation velocity of the crack is measured. The elongation in the upper and lower part of the bellows 12 is offset in this stage and the influence of the atmospheric pressure to the high vacuum is negligible. Therefore, the propagation velocity of the crack is measured precisely in the high vacuum. |
