Measurement of High-Strain-Rate Strength of a Metal-Matrix Composite Conductor

摘要

Castings of metal matrix composites are of potential interest as high strength, high wear resistance conductors. This paper examines the high-strain-rate strength of a tungsten-carbide (WC) filled aluminum bronze alloy (C95400) selected for its good combination of good electrical and thermal conductivity and high mechanical strength, toughness, and wear resistance. A functionally graded material with high wear resistance at the surface was fabricated by centrifugal casting which uses a rotating mold to deposit the high density WC particles at the outer surface while retaining the bulk electrical and thermal conductivity of the bronze alloy for conducting applications. In this paper we evaluate the effects of the WC particles on the dynamic material behavior of the material in the range 500 s~(-1) to 5000 s~(-1). The electromagnetic ring expansion technique was used to obtain a nearly uniform uniaxial tensile stress in a thin ring specimen. The dynamic stress-strain response was evaluated as a function of WC particle content. The technique worked satisfactorily in the pure bronze region of the casting but in the WC filled region near the surface the conductivity was too low to effectively launch the ring specimens.