Rotating-beam fatigue properties of Pd₄₀Cu₃₀Ni₁₀P₂₀ bulk glassy alloy

High-cycle fatigue strength of a Pd₄₀Cu₃₀Ni₁₀P₂₀¹⁾ bulk glassy alloy was examined using the rotating-beam fatigue test. The Pd₄₀Cu₃₀Ni₁₀P₂₀ bulk glassy alloy showed a distinct knee at an applied stress of 0.15 σ_B, (σ_B: tensile strength of 1600 MPa) and a cycle number N = 4 × 10⁷. However, in the equal applied stress of 0.15 σ_B, some samples fractured over the knee cycle numbers. It is likely that the origin of the fracture is to the partial embrittled hardening resulting from crystallization or structural relaxation, which is probably caused by the thermal effect from plastic deformation region. Such a partial hardening by the thermal effect characterizes the fatigue feature of the bulk glassy alloy. It is revealed that no fatigue limit is seen on the Wöhler curve of the Pd₄₀Cu₃₀Ni₁₀P₂₀ bulk glassy alloy.