The effects of loading waveform and microstructure on the fatigue response of Ti-6Al-2Sn-4Zn-2Mo alloy

Abstract

A fractographic analysis was performed to estimate the crack-growth period in specimens of Ti-6AL-2Sn-4Zn-2Mo-0.1Si titanium alloy with two types, α/β and β, of microstructure. The fatigue load cycle shape was triangular or trapezoidal. It was shown that a facetted pattern predominantly forms under the trapezoidal wave shape of cyclic loads for both the investigated microstructures. A special methodology was introduced for quantitative fractographic analysis in the case of locally formed fatigue striations between facetted patterns. Crack-growth periods, estimated on the basis of the striation spacing measurements, were used to determine lifetime to failure for the tested specimens. The results of the performed investigations are briefly discussed and compared with experimental data. © 2005 Blackwell Publishing Ltd.