Resistivity of Short-Range and Long-Range Order Changes in Ni4Mo

Abstract

ABSTRACTShort-range order (SRO) and long-range order (LRO) reactions in Ni Mo as a function of room temperature deformation ahd thermal treatments betwean −269 and 1300°C are Reported. Resistivity results show that SRO is dispersed by heating near 1300°C and by cold working to 68% reduction of area (RA). The resistivity decreases to a minimum at 68% RA after which an increase is attributed to an increase in defect density.The resistivity as a function of variations in the time-temperature history is reported. Cooling at 60°C/min; results in the maximum “frozen in” SRO with resistivity of 144 μohm cm at 25°C; th8 resistivity of the LRO state obtained on slow cooling is 48 μohm cm. At −269°C, the resistivities are 139 and 8 μohm cm for the SRO and LRO states respectively. Correlations relate kinetics and microstructures to resistivity changes during heating, cooling and isothermal SRO-LRO transformations. Preliminary results of reheating fully ordered samples to near 868°C and quenching are reported. Results are discussed with relevance to existing theories.