PHYSICAL MEASUREMENTS ON COPPER-MANGANESE ALLOYS .4. AGING BEHAVIOR OF QUENCHED ALLOYS WITH NICKEL ADDITIONS

The ordered states under equilibrium conditions of ternary copper alloys with constant manganese of 12 mass% have been determined as a function of temperature and amount of nickel. Special attention was focused on the tempering behaviour of the alloys with 2.2 mass% Ni (pure manganin) after quenching by dilatometric and resistivity measurements compared to the results on technical Manganin. During annealing of the quenched alloys instable states are removed in several steps. For pure manganin an annealing diagram for the heating rate 2 K/min was established showing the aging steps and their temperatures as a function of the quenching temperature. In addition, the time and temperature dependence of the recovery process for each tempering step of technical Manganin was examined to interpret the aging processes. Correlating the results for quenched Cu, binary Cu-Mn alloys, pure manganin, and industrial Manganin vacancy and ordering reactions have been identified to cause the aging behaviour. The kinetic of the processes is strongly dependent on heat treatment and on the alloying additions.