Compressive Strength and Fracture Mechanism of Giant Magnetostrictive Materials

Abstract

Compressive strength tests of Giant Magnetostrictive Materials fabricated by powder metallurgy were carried out and the effect of aspect ratio of test pieces and elastic modulus of compression plates were examined. Influential factors on compressive strenght were investigated through observation of fracture behavior, SEM fractography and stress analysis of a specimen near its contact surface. As a result, it was clarified that compressive strength decreased as aspect ratio decreases when elastic modulus of compression plate was high whereas it remained constant without being affected by aspect ratio when elastic modulus was low. This result was well explained by very low tensile strength of Giant Magnetostrictive Materials and tensile stress distribution near the contact surface, which was generated by the difference of elastic deformation between compression plate and test piece.