Compressive Fatigue Strength and Fracture Mechanism of Giant Magnetostrictive Materials Fabricated by Powder Metallurgy

This paper deals with the compressive strength of Terfenol-D type giant magnetostrictive materials fabricated with the powder metallurgy. Static and fatigue compressive tests for the specimens with different porosity were performed. Static compressive tests indicated that the compressive strength of this material can be estimated with the porosity and strength of dense material with same components. Compressive fatigue tests with the same specimens showed that the compressive fatigue strength of this material is 90% to the static compressive strength. Observations of cracks in the specimens were carried out before and after compressive loading. The effects of the compressive stress to the numbers and length of the cracks were examined. Observations showed significant increase of the number of the cracks with length of 5 to 20μm after static and fatigue compressive loading. Fracture processes for static and cyclic loading were proposed.