Accession Number : AD0776212

Title :   J Integral and the Initiation of Crack Extension in a Titanium Alloy,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Yoder,G. R. ; Griffis,C. A.

Report Date : 26 FEB 1974

Pagination or Media Count : 37

Abstract : The J integral has been examined as a criterion for the initiation of crack extension in specimens of an alloy for which crack extension occurs long before maximum load. The Ti-6Al-4V alloy selected is known to be susceptible to the sustained-load-cracking form of subcritical crack growth. Four types of three-point bend specimens were employed: of two different thicknesses (B = 0.5 and 1.0 in.) and two crack lengths (a = 0.685 and 0.885 in.). These fatigue-precracked specimens exhibited, to varying degrees, loading behavior characteristic of the lower end of the elastic-plastic regime. For each specimen type, values of the J integral were obtained as a function of crack extension. Values of the J integral were determined on the basis of a compliance-type calibration which used the plane-stress solutions of Bucci et al. These solutions were found to simulate well the loading curves of the fatigue-precracked specimens. Fore each specimen type, crack extensions were defined by unloading duplicate specimens from various points on the load-displacement diagram and heat tinting.

Descriptors :   *Titanium alloys, *Fracture(Mechanics), Crack propagation, Loads(Forces), Elastic properties, Aluminum alloys, Vanadium alloys

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE