STP426: Effects of Heat-Treatment and Irradiation on the High Temperature Tensile Properties of Austenitic Stainless Steels

    Harries, D. R.
    Atomic Energy Research Establishment, Harwell, Didcot, Berks.

    Roberts, A. C.
    Atomic Energy Research Establishment, Harwell, Didcot, Berks.

    Pages: 27    Published: Jan 1967


    Abstract

    The effects of boron content and heat treatment on the microstructures, high temperature tensile properties, and fracture behavior of unirradiated and irradiated 18Cr-10Ni-Cb stabilized austenitic steel have been investigated. The location and distribution of the boron were determined using an autoradiographic technique. The results support the view that boron has a dual role in the irradiation-induced high temperature embrittlement of austenitic steels in that the helium formed by the 10B(n,α)Li7 reaction is detrimental but that boron itself exerts a beneficial effect.

    Studies have also been made of the effects of heat treatment on the high temperature tensile properties of irradiated 20Cr-25Ni-Cb stabilized austenitic steel, and it has been shown that aging at 750 C either before or after irradiation at 45 C improves the high temperature tensile ductility of the solution treated steel. The observations have been interpreted in terms of (1) the beneficial effects of intergranular carbide precipitates produced by aging before irradiation on grain boundary fracture behavior and (2) fine carbide precipitates nucleated within the grains by aging after irradiation pinning helium bubbles and thereby preventing them from diffusing to the grain boundaries.

    Keywords:

    irradiation, heat treatment, tensile properties, steels, stainless steels, radiation effects, boron, microstructure, fracture, auto-radiography, embrittlement, helium, aging


    Paper ID: STP41316S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP41316S


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