A technique is described for measuring torsional wave velocity in (nonferromagnetic) wire with diameters of less than 1 mm. Transduction is noncontacting, via Lorentz forces acting across a gap between transducer and wire, so that velocity can be rsquo;rsquo;scannedrsquo;rsquo; along the length of the wire. A doublehyphen;receiver approach permits the scan to be made in a rsquo;rsquo;pointhyphen;byhyphen;pointrsquo;rsquo; fashion. The wires are a metalhyphen;matrix composite of 6061 aluminum and pitch mesophase graphite. Some data are presented, together with a discussion of the effects of metalhyphen;matrixhyphen;composite parameters, such as graphite content and porosity, on torsional velocity. An extrapolation of our metalhyphen;matrixhyphen; composite data yields a value forc44, of the graphite fiber, that was within 1percnt; of a value determined from data of Fischbach and Scrinivasagopalan. Good predictions of experimental results were obtained through use of theory of Hashin and of Achenbach and Herrmann. Some differences, and their implications, between torsional and longitudinal waves propagating in metalhyphen;matrixhyphen;composite wire are described.
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