The Variation of the Internal Friction and Elastic Constants with Magnetization in Iron. Part I

Abstract

A new and precise method is described for measuring the elastic constants and coefficients of internal friction of solid substances. The method is applied to investigate the variation of Young's modulus and the longitudinal coefficient of internal friction of annealed and unannealed Armco iron with magnetization at room temperature. Data are given which describe the behavior of the iron in three different magnetic states, viz., at different points on the normal induction curve and on a hysteresis cycle, and in the anhysteretic state obtained when an alternating field, the amplitude of which is gradually reduced to zero, is superposed on a steady magnetizing field. The observed coefficients of internal friction of the unannealed specimen require correction, and this, together with the torsional data and theoretical interpretation of the results, are given in Part II of this paper.