Electrical Resistivity of Liquid Fe–Mn Alloys

The paper deals with the specific electrical resistivity of liquid Fe–Mn alloys with the manganese content of 3.9, 6.0, 8.2, 10.3 and 13.2 at.%. A rotary-field electromagnetic method is used to measure this parameter. The experiments are conducted under heating conditions in the range from 1720 to 2070 K followed by the specimen cooling in pure helium. Most of alloys demonstrate a kink on the temperature curve of the specific electrical resistivity during heating up to 1900–2000 K. It is found that the specific electrical resistivity and the ratio between the conductivities of the liquid alloys and the inclusion grow with increasing manganese content in the alloy. Theoretical calculations are performed for the effective specific electrical resistivity of the liquid Fe–10 at.% Mn alloy in the temperature range 1720 to 2770 K. The certain temperature is determined, when the conductivity of the heterogeneous liquid alloy equals the conductivity of the iron solution in manganese with the uniform atom distribution. The obtained values of the certain temperature range between 2050– 2100 K, i.e., are higher than 1900–2000 K, at which the kink appears on the temperature curve of the electrical resistivity. Theoretical studies are presented for the percolation transition in heterogeneous liquid Fe–Mn alloys. The limit value is identified for the ratio between the electrical resistivity of liquid alloys and the inclusion, when a percolation transition is possible. The percolation threshold is determined as a volume fraction of inclusions, at which the effective specific electrical resistivity significantly reduces. The latter is calculated for the heterogeneous liquid alloy in the Maxwell approximation (interpreted by А. А. Snarskii).