APPLICATION OF THE VILLARI EFFECT IN A FATIGUE EXAMINATION OF NICKEL

This paper presents the possibility of using the reverse magnetostrict ion (Villari) effect in fatigue testing of ferromagnetic materials. Th e tests were conducted on cyclically loaded nickel with no auxiliary e xternal magnetic held. The following properties were determined: magne tic induction B, magnetic held strength H, energy of the magnetic hyst eresis loop Delta M (in the B-H coordinate system), plus such mechanic al quantities as stress sigma strain epsilon, plastic strain epsilon(p ) and energy of the mechanical hysteresis loop Delta W (in the sigma-e psilon coordinate system). A variety of magneto-mechanical characteris tics are presented and their susceptibility to loading parameters of t he fatigue process are discussed. A relationship between Delta W and D elta M is demonstrated. The Villari effect is shown to be especially u seful in determining the cyclic yield limit.