Fatigue crack growth behaviors in Al−Si−Mg sand cast alloys

Abstract

The fatigue crack growth behavior of Al-Si-Mg sand cast alloys has been investigated with reference to the effects of solidification structure and aging condition. Fatigue crack growth tests have been carried out under constant load amplitude and a stress ratio of R=0.1 using CT specimens. The amount of pores in the matrix was limited by performing HIP treatment. The pores tended to promote deflection of fatigue cracks, which decreased the fatigue crack growth rate at low ΔK regions and increased the number of cycles until final fatigue fracture. Refining and spheroidizing of eutectic Si particles increased the fatigue crack growth rates over a wide range of ΔK up to larger ΔK values. The difference of aging conditions significantly affected the da/dN-ΔK eff relationship.

Evaluation of Un-Cracking Delamination by Pseudo Crack Model (PCM) in FRMLs

“…It was generally known that the delamination of FRMLs was caused by the crack of Al alloy layers and it depends on the crack growth [1]. Since these results were obtained from the fatigue behavior of specimens with a saw-cut, the delamination always depends on the crack apart from the loading type [2]. In the meantime, due to the geometric distinction, the fatigue behavior of the circular hole notch is different from that of saw-cut one.…”