Fatigue properties and microstructures of Zr₅₅Cu₃₀Al₁₀Ni₅ bulk glassy alloys

The fatigue strength and the fatigue crack propagation of Zr₅₅Cu₃₀Al₁₀Ni₅ bulk glassy alloys were examined using fully glassy plate shape samples produced by metallic mold casting. Fatigue testing was done under a tensile-tensile stress condition with a stress ratio R(σ_max/σ_min) = 0.5. As the results, we could confirm that the Wohler curve is different from those of ordinary crystalline structural alloys in that the fatigue strength decrease significantly from N = 10³ to 10⁴. Besides, the crack propagation rate of the samples were examined with macroscopic mechanical testing and microscopic fracture surface observation, and the both methods lead to the same result that the forced factor is about 2 with a power-law.