Orientation Dependence on Fatigue Fracture Behavior in Uniaxial Fatigue Tests of Pure Mg Single Crystals

Abstract

Three Mg single crystalline round-bar specimens with different crystal orientations were subjected to uniaxial tension-compression fatigue tests, and crystal orientation dependence on fatigue fracture behavior was investigated. Loading directions of AD, BC and EF specimens were [1120] [1100] and [0001] respectively. Results show that, at stress amplitude (σ_a) greater than or equal to 60 MPa, fatigue life of BC specimen was longest, while that of EF specimen was shortest. Under stress amplitude of 20 MPa, crystal orientation dependence on fatigue lives was not confirmed. Our study suggests that fatigue life in Mg single crystals show a high degree of dependence on crystal orientation and stress.