Einfluß von Neutronenbestrahlung bei 4 °K auf den Schermodul von Kupfer, Aluminium und Platin

Abstract

Abstract The change of the shearmodulus of pure polycrystalline Al, Cu and Pt due to reactor neutron irradiation at 4 °K has been studied. The shearmodulus was determined by measuring the vibrational frequencies of a helical spring in two different modes (between 50 and 300 Hz) together with internal friction and electrical resistance. Large relative decreases of the shearmodulus ΔG/G per molar fraction c of Frenkel defects were found, namely ΔG/Gc - 47, - 39, - 67 for Al, Cu and Pt, respectively. The absolute values are much larger than expected from lattice theory. The effects cannot be explained by a relaxation of the defects.