SYMPOSIA PAPER Published: 01 January 1975

Postirradiation Properties of the 6061-T6 Aluminum High Flux Isotope Reactor Hydraulic Tube


A tube of 6061 aluminum alloy in a T6 temper, precipitation-hardened with Mg2Si, was examined after irradiation in the core of the High Flux Isotope Reactor to fluences up to 1.3 × 1023 neutrons (n)/cm2 (0.1 MeV) and 3.1 × 1023 n/cm2 (thermal) in contact with the cooling water at a temperature of about 55°C. The alloy displayed up to 2.5 percent swelling due mainly to a precipitate of transmutation-produced silicon of which more than 6 weight percent was formed. Some cavities were also observed. Tension tests in the temperature range 55 to 200°C showed radiation-induced increases in yield stresses and ultimate stresses of 50 to 80 percent; elongation was reduced from the range 10 to 15 percent to about 5 percent at 55C° and to about 3 percent at test temperatures above 100C°. The fracture mode ws changed from transgranular tearing around inclusions to a mixture of transgranular tearing and ductile intergradular separation. These changes are attributed primarily to the radiation-induced silicon precipitate. A rim of intergranular cracks formed at the originally oxidized surfaces of the tube during tension testing and became deeper with increasing neutron irradiation and increasing temperature.

Author Information

Farrell, K
Oak Ridge National Laboratory, Oak Ridge, Tenn.
Richt, AE
Union Carbide Corporation, South Charleston, W. Va.
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Developed by Committee: E10
Pages: 311–325
DOI: 10.1520/STP33695S
ISBN-EB: 978-0-8031-4653-2
ISBN-13: 978-0-8031-0539-3