The Fatigue and Tensile Properties of Dispersion Strengthened Copper at Low Temperatures (77 to 295K)

Abstract

High-field pulsed-magnets are subject to high operational forces and rapid temperature excursions. These magnets typically are precooled to 77 K and experience a temperature rise to about room temperature in times of 100 ms or less. Peak stresses in the magnet windings coincide with a temperature of about 195 K and are limited only by the magnet performance requirements or the strength of the materials used. Alumina dispersion strengthened copper alloys (D.S. coppers) have been proposed for pulsed magnet applications as a replacement for the heavily cold-worked, unalloyed coppers presently used for the windings. Here we report the results of mechanical testing of three dispersion strengthened copper alloys having alumina contents ranging from 0.3 to 1.1 wt. %. Specifically, we have evaluated the tensile properties of these alloys and their fatigue lives (S-N) near the low cycle regime. Properties are reported for several temperatures intermediate to 77 K and 300 K, including 195 K.