Takamichi Maruyama1, Ken-ichi Sato2 and Minoru Yokota2
1EOD, JEOL Ltd., Tokyo
The magnetic susceptibilities of Cu-Cr alloys containing 0.122 and 0.244 at% Cr were measured at room temperature. The Cu-Cr alloys were solution-treated at 950°C for 2 hr, quenched into water and cold-drawn into wires of 0.5 mm φ . The wires were aged for 2 hr over at a temperature range 400°C to 700°C. The pure Cu wires were prepared by the same process.
The amount of dissolved Cr in Cu of each specimen was determined from the difference between electrical resistivities of the alloy and Cu at 4.2 K.
The change in magnetic susceptibility of Cu-Cr alloys by aging can be explained by the change in the amount of dissolved Cr. The magnetic susceptibility at room temperature was estimated from the simple sum of the susceptibilities of dissolved Cr and precipitated Cr. The results agreed well with the measured values. The effective Bohr magneton value and the Weiss temperature of dissolved Cr in Cu were determined as 3.6 and -8 K, respectively, by using the Curie-Weiss law.
A practically important alloy which has very low magnetic susceptibility (≈-3×10-8 emu/g) and high conductivity (90% IACS) was found in these Cu-Cr alloys aged at 700°C for 2 hr.
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