The Internal Friction of Metals

Abstract

Soundly based metallurgical interest in the internal friction of solids dates from the appearance of Zener's text “Elasticity and Anelasticity of Metals” in 1948. This scholarly and pithy work presents an analysis of the mechanical behaviour which arises if the process of transition between the unstressed and the stressed equilibrium states is delayed and is accompanied by a change in dimensions of the solid. In these circumstances the relation between decrement and frequency of vibration has characteristic maxima which can be used to give information on the specific mechanism causing the peak. Zener has listed and analysed several such processes, for example the thermoelastic effect, ordering of solute atoms under stress, deformation at crystal boundaries, and eddy currents generated by mechanical vibration. Of these loss mechanisms, that of solute-atom ordering has contributed most to new knowledge on the behaviour of alloys; this is evident in the prominence given to it by Nowick in his review of internal friction up to 1951 and in later reviews by Entwistle. More recently, significant new work has appeared to justify making the topic of stress-induced ordering an important part of the present review.