Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Effect of Nb-content and Cooling Rate during ${\beta}$-quenching on Phase Transformation of Zr Alloys

${\beta}$-열처리시 Nb 첨가량과 냉각속도가 Zr 합금의 상변태에 미치는 영향

  • Choi, B.K. (Zirconium Fuel Cladding Team, Korea Atomic Energy Research Institute) ;
  • Kim, H.G. (Zirconium Fuel Cladding Team, Korea Atomic Energy Research Institute) ;
  • Jeong, Y.H. (Zirconium Fuel Cladding Team, Korea Atomic Energy Research Institute)
  • 최병권 (한국원자력연구소, 지르코늄신합금 핵연료피복관 개발팀) ;
  • 김현길 (한국원자력연구소, 지르코늄신합금 핵연료피복관 개발팀) ;
  • 정용환 (한국원자력연구소, 지르코늄신합금 핵연료피복관 개발팀)
  • Received : 2004.03.10
  • Accepted : 2004.07.19
  • Published : 2004.09.30
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Abstract

Zr-xNb alloys (x = 0.2, 0.8, 1.5 wt.%) were prepared to study the characteristics of the phase transformation in Zr-Nb system. The samples were heat treated at ${\beta}$-temperature ($1020^{\circ}C$) for 20 min and then cooled with different cooling rate. The microstructures of the specimens having the same compositions were changed with cooling rate and Nb content. The Widmanst$\ddot{a}$tten structure was observed on the furnace-cooled sample. The relationship between ${\alpha}$-Widmanst$\ddot{a}$tten and ${\beta}$-phase was the {0001}${\alpha}$//{110}${\beta}$, <11$\bar{2}$0>//<111>. The ${\beta}$-phase in Widmanst$\ddot{a}$tten structure of Zr-Nb alloys containing Nb more than solubility limit was identified as ${\beta}_{Zr}$ phase which was a stable phase at high temperature. In the water quenched samples, two kinds of martensite structures were observed depending on the Nb-concentration. The lath martensite was formed in Zr-0.2, 0.8 wt.% Nb alloys and the plate martensite having twins was formed in Zr-1.5 wt.% Nb alloy.

Keywords

Acknowledgement

Supported by : 한국원자력연구소

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