Effect of Ge content and annealing temperature on resistance properties of Cu-8Mn alloy

Abstract

The as-cast Cu-8Mn-xGe (x=0, 1.35wt%, 1.7wt%, 2.2wt%) alloys were prepared by horizontal continuous casting process. The annealed alloy samples were obtained by multi-pass drawing and annealing process. The effects of Ge content and annealing temperature on the resistivity and resistance temperature coefficient of the alloys were investigated by means of optical microscope, scanning electron microscope, DC resistance tester and resistance temperature coefficient tester. The results show that the resistivity of Cu-8Mn-xGe alloy increases from 0.26 µΩ•m to 0.36 µΩ•m with the increase of Ge content. The resistivity of Cu-8Mn-1.7Ge alloy decreases with the increase of annealing temperature. In terms of the temperature coefficient of resistance (TCR), the TCR of Cu-8Mn-xGe alloy decreases with the increase of the content of Ge atom, from 21.74 × 10-6 °C-1•to -13.00 × 10-6 °C-1. The TCR of Cu-8Mn-xGe alloy is significantly reduced by Ge element. The TCR of Cu-8Mn-1.7Ge alloy increases with the increase of annealing temperature from 26.90 × 10-6 °C-1 to 118.00 × 10-6 °C-1. In terms of microstructure, the average grain size of Cu-8Mn-1.7Ge alloy increases from 5.68µm to 22.06µm with the increase of heat treatment temperature.