Effects of irradiation on the fracture toughness of Alloy 718 plate and weld

Technical Report · Thu Jul 01 04:00:00 EDT 1982

OSTI ID:5563803

Mills, W J

The effect of fast-neutron irradiation on the J{sub Ic} fracture toughness of Alloy 718 plate and weld was characterized at 427{degrees}C using single- and multiple-specimen R-curve techniques. Two heat treatments were employed: the conventional ASTM A637 precipitation heat treatment (CHT) and a modified heat treatment (MHT) designed to improve the impact toughness of Alloy 718 welds. In the unirradiated and irradiated conditions, the fracture resistance of the MHT materials was consistently higher than that of their CHT counterparts. Irradiation significantly reduced the J{sub Ic} and tearing modulus values for the plate and weld in both heat-treated conditions with saturation occurring at relatively low neutron exposures (below 8 dpa). The CHT base metal and weld exhibited saturation J{sub Ic} levels of 31 and 21 kJ/m{sup 2}, respectively, a saturation level of 52 kJ/m{sup 2} was obtained for both the MHT wrought product and weld metal. Electron fractographic examination revealed that irradiation damage induced a transition from microvoid coalescence to channel fracture, which is associated with localized separation along intense, planar slip bands. The effects of microstructure and operative fracture mechanisms are related to the fracture resistance of unirradiated and irradiated Alloy 718. 30 refs., 12 figs., 5 tabs.

• Research Organization: Hanford Engineering Development Lab., Richland, WA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76FF02170
• OSTI ID: 5563803
• Report Number(s): HEDL-TME-82-1; ON: DE91015598
• Country of Publication: United States
• Language: English

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