The effects of sustained load (crack growth) testing in inertia friction welded Udimet 720Li turbine disc alloy at elevated temperatures

Snodin, Katie Amelia (2011). The effects of sustained load (crack growth) testing in inertia friction welded Udimet 720Li turbine disc alloy at elevated temperatures. University of Birmingham. M.Res.

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Abstract

In order to improve aero engine efficiency there has been continuing development on materials to enable engine components such as turbine discs to be operated successfully under more rigorous conditions (Ewing et al., 2003).This means the service life of these highly stressed components will be determined by modes of degradation and failure which include fracture, creep, oxidation and corrosion damage (Witek, 2006; Pang and Reed, 2007). However, the main threat to turbine disc life is the initiation and propagation of fatigue cracks and so an understanding of crack nucleation and growth under mechanical loading is vital if in service failures are to be avoided.

The crack growth resistance of inertia friction welded Udimet 720Li (U720Li) disc alloy, when subjected to sustained load (crack growth) tests has been investigated over a range of temperatures (300-725 °C) in air, and in vacuum at the test temperature of 700 °C for corner-cracked testpieces containing a sharp fatigue pre-crack and tested in uniaxial tension. Characterising crack growth behaviour in welds is fundamental in providing an understanding of the relative effects of fatigue, creep and oxidation on the high temperature performance of nickel-based superalloys.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

Supervisor(s):