The Recovery Phenomena of the Cold Worked Pure Zirconium

In the ,present study, recovery behaviour of cold compressed pure zirconium was investigated by the measurement of X-ray line breadth and microhardness. By isochronal annealing, it was found that both hardness and X-ray line breadth do not show remarkable decrease below 300"e. It was also found that at the same degree of cold work, the rate of recovery of X-ray line breadth is different from that of hardness, and that regardless of cold working degrees, activation energy for the recovery of X-ray line breadth is less than that of hard ness. Activation energies for recovery of X-ray line breadth in 8%, 19% and 28% cold worked zirconium were 64,800 cal/gram atom, 56,400 cal/gram atom and 48,500 cal/gram atom, respectively, and those of hardness were 72,800 cal/ gram atom, 64,300 ca1/9ram atom and 58,600 ca119ram atom, respectively.vely.

냉간 압축가공한 순수 지르코늄의 회복현상을 X-ray line broadening과 미소경도 (microhardness)를 측정하여 연구하였다. Isochronal 소둔한 결과에서 경도나 X-ray line breadth가 30$0^{\circ}C$이하에서는 감소하지 않는다는 것을 알 수 있었다. 같은 크기의 냉간가공도에서 X-ray line breadth의 회복속도는 경도의 회복속도와 다르게 나타났으며 가공도에 상관없이 X-ray line breadth의 회복에 필요한 활성화 에너지는 경도의 회복에 필요한 활성화 에너지보다 작은 것을 알 수 있었다. 8%, 19%, 28% 냉간가공한 지르코늄에서의 X-ray line breadth의 회복에 필요한 활성화 에너지는 각각 64,800cal/gram atom, 56,400 cal/gram atom, 48,500 cal/gram atom이였으며 경도의 회복에 필요한 활성화 에너지는 72,800 cal/gram atom, 64,300 cal/gram atom, 58,600 cal/gram atom인 것으로 나타났다.