EFFECT OF NEUTRON IRRADIATION ON MATERIALS SUBJECTED TO MULTI-AXIAL STRESS DISTRIBUTIONS. Quarterly Report for the Period Ending June 30, 1962

Activities in a program to determine the effects of neutron irradiation on A-302B steel are reported. Plans are discussed concerning performance tests on tensile, notched tensile, tube, and Charpy specimens. An irradiation capsule design was finalized. A theoretical analysis of the critical conditions arising in a tube subjected to both internal pressure and axial load is included. (J.R.D.

A Program of Basic Research on Mechanical Properties of Reactor Materials. Quarterly Progress Report for the Period Ending June 30, 1963

Deformation Mechanisms in BCC Metals. Thin-film microscopic observations are presented for rolled single TA crystals. These observations show numerous areas almost devoid of slip markings. One specimen was annealed in air at 400 deg C to pin all the dislocations; transmission micrography of the annealed specimen indicates a quite low temperature for dialocation rearrangements. A correlation was found between the temperatures of the stages in the amplitude-dependent modulus defect and the deformation-peak temperatures for Nb. It is concluded that much inore extensive dislocation motion is possihle for a given applied stress amplitude at temperatures above the alpha peak than below, and that limited dislocation motion is possible at very low temperatures if the applied stress is great enough. Stored-Energy Release in Deformed Metals. Stored-energy-release measurements were made on Puron and Ferrovac E grades of pure Fe for several grain sizes and strain levels. The results indicate that the stored energies and dislocation densities in Fe are much smaller than in Cu and other metals. (D.L.C.