단 범위 규칙 반응이 Zr-2.5%Nb 압력관 재료의 시효(aging) 현상에 미치는 영향 (Effects of Short Range Ordering on Aging Phenomenon in Zr-2.5%Nb Pressure Tube Material)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 56권 / 7호 / 479 ~ 489페이지
· 저자명 : 김성수, 김영석, 정종엽

초록

This study was conducted to investigate the effect of aging treatment from 300 oC to 420 oC on the mechanical properties of the pressure tube material at 310 oC, which is outlet temperature pressure tube in CANDU reactor. The short range ordering (SRO) phenomenon during aging process is confirmed by differential scanning calorimetry (DSC), TEM, and slow strain rate tensile test. As-received and aged pressure tube materials exhibit a sudden stress drop in stress at 50 MPa or less when subjected to tensile strain at a strain rate as low as 1 × 10-6/s at 310 oC. This is an evidence of destruction of SRO formed in the initial and the aged state. The yield and tensile strengths decreased by 4-11% by aging treatment at 300-420 oC for 3,000 hours. Through the DSC analysis, the quadruple-melted pressure tube materials showed an exothermic reaction at around 410 and 590 oC in the heating process. This is due to SRO reaction, and the activation energy for the exothermic reaction at around 590 oC is obtained as Q = 90 kJ / mole. This reaction seems to be related to the formation of SRO between Zr and O (oxygen) which is dominated by grain boundary diffusion of oxygen in α-Zr. The effects of strain rate and short range ordering (SRO) were discussed in detail.

영어초록

This study was conducted to investigate the effect of aging treatment from 300 oC to 420 oC on the mechanical properties of the pressure tube material at 310 oC, which is outlet temperature pressure tube in CANDU reactor. The short range ordering (SRO) phenomenon during aging process is confirmed by differential scanning calorimetry (DSC), TEM, and slow strain rate tensile test. As-received and aged pressure tube materials exhibit a sudden stress drop in stress at 50 MPa or less when subjected to tensile strain at a strain rate as low as 1 × 10-6/s at 310 oC. This is an evidence of destruction of SRO formed in the initial and the aged state. The yield and tensile strengths decreased by 4-11% by aging treatment at 300-420 oC for 3,000 hours. Through the DSC analysis, the quadruple-melted pressure tube materials showed an exothermic reaction at around 410 and 590 oC in the heating process. This is due to SRO reaction, and the activation energy for the exothermic reaction at around 590 oC is obtained as Q = 90 kJ / mole. This reaction seems to be related to the formation of SRO between Zr and O (oxygen) which is dominated by grain boundary diffusion of oxygen in α-Zr. The effects of strain rate and short range ordering (SRO) were discussed in detail.

참고자료

· 없음