# Mechanisms of cleavage during fatigue crack growth in $Ti-6Al-4V$ alloy

Ravichandran, KS and Dwarakadasa, ES and Banerjee, D (1991) Mechanisms of cleavage during fatigue crack growth in $Ti-6Al-4V$ alloy. In: Scripta Metallurgica et Materialia, 25 (9). pp. 2115-2120.

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Official URL: http://dx.doi.org/10.1016/0956-716X(91)90284-8

## Abstract

Beta processed microstructures of titanium alloys consisting of Widmanstatten structures offer attractive combinations of strength, fracture toughness and resistance to fatigue crack growth (FCG) for damage-tolerance applications [1-3]. This is generally attributed to large prior beta grain sizes incorporating coarse lamellar colonies across the boundaries of which cracks are deflected or deviated [4]. FCG resistance of these microstructures is far superior that of other microstructures owing to increased levels of crack deflection or deviation causing an increase in the intrinsic crack growth resistance, $\Delta K_e_f_f_,_t_h$, as well as crack closure [5]. However, the fatigue crack initiation resistance is lowfor these structures due to the formation of large intense planar slip bands. Growth of fatigue cracks along these bands normal to $\alpha/\beta$ interfaces is easy without interruption at the interfaces and this has been largely attributed [6] to the poor fatigue crack initiation characteristics, tn the present study, some important and unusual fracture features pertaining to the effect of $\beta$ phase in retarding cleavage cracks produced during fatigue crack growth are presented. The factors responsible for these effects are highlighted.

Item Type: Journal Article Copyright of this article belongs to Elsevier Science. Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) 26 Jun 2007 17 Jan 2012 05:35 http://eprints.iisc.ernet.in/id/eprint/11269