Mechanical anisotropy, strain aging, and deformation mechanisms in zirconium and zirconium-niobium alloys. [Temperature range 298-673 K]
The tensile properties of zirconium, Zr-0.5 Nb-0.8 Bi, and Zr-2.5 Nb alloys in an annealed condition were evaluated in the rolling (RD) and transverse (TD) directions in the temperature range of 298 to 673 K at three different strain rates. Zirconium does not exhibit sharp yield points in either RD or TD in the temperature and strain rate ranges studied. While the yield strength (YS) or ultimate tensile strength (UTS) values are not influenced by the direction of testing or strain rate at any temperature of testing, the tensile ductility is superior in the Rd than in the TD, and the YS and UTS decreased gradually with increasing temperature. The Zr-0.5 Nb-0.8 Bi, and Zr-2.5 Nb alloys exhibit discontinuous yielding in all conditions studied. The yield stress in the TD is slightly higher than that in the RD, and the ultimate tensile strength is higher in the RD. The strain rate sensitivity, however, decreases slightly above 573 K, indicating a very weak dynamic strain aging effect. The study indicates that zirconium deforms by a mixed mode of prismatic slip and twinning on (10{bar 1}2) and (11{bar 2}1) planes in the RD and TD specimens, respectively, while Zr-0.5 Nb-0.8 Bi, and Zr-2.5 NB alloys exhibit no sign of twinning but only prismatic slip when deformed along the Rd or the TD direction.
- Research Organization:
- North Carolina State Univ., Raleigh, NC (United States)
- OSTI ID:
- 7163464
- Country of Publication:
- United States
- Language:
- English
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