Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2013.09.029· OSTI ID:1120473

Baek, Jong-Hyuk ^[1]; Byun, Thak Sang ^[2]; Maloy, S ^[3]; Toloczko, M ^[4]

---

1. KAERI
2. ORNL
3. Los Alamos National Laboratory (LANL)
4. Pacific Northwest National Laboratory (PNNL)

The temperature dependence of fracture toughness in HT9 steel irradiated to 3 145 dpa at 380 503 C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm 3mm 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 C, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180 200 MPa ffiffiffiffiffi m p at 350 450 C, and then decreased with the test temperature. At an irradiation temperatureP430 C, the fracture toughness was nearly unchanged up to about 450 C and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1120473
• Journal Information: Journal of Nuclear Materials, Vol. 444, Issue 444; ISSN 0022-3115
• Country of Publication: United States
• Language: English