Study of Heat Treatments for Low Coercive Force 14 to 17% Aluminum Iron Alloys

Abstract

A study was made of the effects of atmosphere, temperature of initial annealing, and composition on the coercive force of 14 to 17% Al-Fe alloys. A combined effect of heat treatment atmosphere and temperature of initial annealing is shown to exist in this alloy region, and is discussed in terms of a possible influence of purification and atomic ordering. The unique feature of these alloys is that heat treatments in air at 900°C produce lower coercive force values than heat treatments in dry hydrogen at the same temperature. This factor would make the heat treatments of these alloys more economical than those of other standard high-permeability alloys. Observations made on the binary Al-Fe iron alloys apply to the heat treatment of Al-Fe alloys containing ternary additions. These observations also show that the heat treatment controls both the grain size and the distribution of the second phase in ternary alloys, which in turn affect the magnetic properties.