Deflected teardrop cracking in nickel based superalloys: sustained macroscopic deflected fatigue crack growth


Schoettle, C., Sinclair, I., Starink, M.J. and Reed, P.A.S. (2012) Deflected teardrop cracking in nickel based superalloys: sustained macroscopic deflected fatigue crack growth. International Journal of Fatigue, 44, 188-201. (doi:10.1016/j.ijfatigue.2012.04.017).

Download

[img] PDF - Publishers print
Restricted to System admin

Download (3541Kb) | Request a copy

Description/Abstract

A sustained macroscopic deflected fatigue crack growth, the so-called ‘tear drop’ crack (TDC), has been observed under mode I (tensile) loading in Udimet 720Li when tested at 300°C in air and at 300, 600 and 650°C in vacuum. A definition of the onset of sustained shear crack growth is proposed and applied to different test geometries in different temperatures and environments. SEM analysis of the fracture surfaces have shown a competition between the sustained shear and mode I crack growth modes in both the terraced shear lip and flat tear drop region, which indicates that the macroscopic deflection is triggered by the free surface.

The tilt angles measured from the deflections have been used to define a mixed mode plane stress test, attempting to replicate the stress state giving rise to deflected shear growth.

Item Type: Article
ISSNs: 0142-1123 (print)
Keywords: nickel based superalloys, teardrop cracking, sustained deflected fatigue crack growth, mixed mode
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TN Mining engineering. Metallurgy
Divisions: Faculty of Engineering and the Environment > Engineering Sciences > Engineering Materials Surface Engineering
ePrint ID: 339007
Date Deposited: 21 May 2012 14:10
Last Modified: 27 Mar 2014 20:22
URI: http://eprints.soton.ac.uk/id/eprint/339007

Actions (login required)

View Item View Item