Influence of Sample Configuration and Crack Orientation on Fracture Toughness of Zr-2.5Nb Alloy Pressure Tube

doi:10.3901/JME.2025.12.173

Abstract

Abstract: Fracture toughness is one of the necessary mechanical parameters to evaluate the safety of Zr-2.5Nb alloy pressure tubes. The fracture toughness research of pressure tubes using small specimens has the advantages of less material, simplified test procedures, more economical. Especially for the fracture toughness assessment of irradiated pressure tube, the advantages of small specimens compared with the fracture toughness of the original tubes measured by rising pressure burst test are more prominent. Single edge-notched bending(SEB) and compact tension(CT) specimens with different crack orientations were used to perform fracture tests on domestic Zr-2.5Nb alloy pressure tubes at room temperature, and the influence of specimen configuration and crack orientation on the fracture toughness was investigated. The results show that the hoop yield strength and tensile strength of domestic Zr-2.5Nb alloy pressure tubes are significantly higher than the axial properties. The axially cracked CT specimen presents the highest fracture toughness of the pressure tube, and the circumferentially cracked SEB specimen gets the lowest value, and the crack orientation has little effect on the fracture toughness of the two type of the SEB specimens. The growing crack of the CT specimen is significantly affected by the curved surface structure, showing the “mountain” character, while the flatness of the growing crack front of the SEB specimen is better. Compared with the axially cracked CT specimens, it is safer to use the circumferentially cracked SEB specimens for fracture safety evaluation of Zr-2.5Nb alloy pressure tubes.

Key words: domestic Zr-2.5Nb alloy pressure tube, fracture toughness, SEB specimen, CT specimen, crack orientation

CLC Number:

O346

WU Zhiyi, CAO Yupeng, ZHAO Guannan, XU Xikai, BAO Chen. Influence of Sample Configuration and Crack Orientation on Fracture Toughness of Zr-2.5Nb Alloy Pressure Tube[J]. Journal of Mechanical Engineering, 2025, 61(12): 173-181.

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