Effects of Cerium on Crystal Orientation Dependence of Fatigue Fracture Behavior of Magnesium Single Crystals

抄録

Fatigue tests of single crystalline Mg–0.026 at%Ce were carried out to investigate the effects of cerium on crystal orientation dependence of fatigue lives. Three crystal orientations were investigated: B specimen with [1100](0001)], D specimen with [1120](1100)] and E specimen with [0001](1120)]. Fatigue lives increased by the cerium addition in D and E crystal orientations, but decreased in B crystal orientation. The cerium additions decreased critical resolved shear stress (CRSS) for second order pyramidal slip, resulting in ridge and stripe (RS) patterns which were observed on fracture surfaces in B specimen. A fatigue crack propagation mechanism was proposed to account for the RS patterns.

Fig. 9 SEM images of (a) fatigue fracture surface of B specimen of Mg–Ce single crystals at a stress amplitude of 120 MPa, (b) ridge and stripe (RS) patterns and (c) coarse grooves in the center of B specimen.