The Electrical Resistance of Metals and Alloys in Their Hard and Soft States

It is known that the electrical resistance of annealed metals is usually smaller than that of metals in their cold worked state. The curve showing the relation between electrical resistance and annealing temperature reaches a minimum; continued annealing at higher temperature produces an increase in the electrical resistance. In the case of alloys it has been noted that a second decrease occurs at higher annealing temperature. The following work corroborates the observance of previous investigations. The electrical resistance of cold worked copper, gold, nickel, and iron decreased with annealing and then increased, the minimum being around 300° C. or 400° C. Monel metal showed a minimum resistance followed by an increase which in turn was followed by a second decrease.

The Electrical Resistance of Metals in their Hard and Soft States

Many investigations have shown that the electrical resistance of soft annealed metals is usually smaller than that of metals in their hard, cold worked state. By annealing cold-worked metals, the electrical resistance decreases to a minimum and then increases upon continued annealing at higher temperatures. The work performed in this investigation upon silver, aluminum, copper, nickel, and soft steel corroborates this idea.