MAGNETOABSORPTION TECHNIQUES FOR MEASURING MATERIAL PROPERTIES.
Technical rept. Jan 65-Jan 66,
SOUTHWEST RESEARCH INST SAN ANTONIO TX
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Research was continued to determine the feasibility of using magnetoabsorption for the nondestructive evaluation of material properties. Previous efforts, reported in ML-TDR-64-123 and AFML TR-65-17, have shown that magnetoabsorption signals are derived from variations of the reversible permeability of ferromagnetic specimens with magnetic environment. Further, it had been shown that magnetoabsorption signals are readily affected by changes in reversible permeability as caused by stress, heat treatment, composition, impurity, and temperature. The effort of this period has been devoted to a refinement of the magnetoabsorption measuring equipment to detect low amplitude magnetoabsorption signals from specimens offering a small effective filling factor to a sample coil or probe. These refinements are primarily discussed in the Appendices. With this improved sensitivity, variations in harmonic content of magnetoabsorption signals arising from variations in the surface properties of a plate of maraging steel were related experimentally. Magnetoabsorption waveforms were also measured from and related to a weldment of maraging steel, stressed and stress-relieved specimens of HY-80 steel, and a bulge plate of 1020 steel. Magnetoabsorption signal changes and its harmonic amplitude variations from nickel-plated aluminum rods and other ferromagnetic wires were related experimentally to applied compressive and tensile loads. Author
- Metallurgy and Metallography
- Test Facilities, Equipment and Methods