Single Crystal Turbine Blades

Single crystal blade materials have found extensive use in high temperature service applications such as rotating aerofoils and static vanes in the gas turbine due to a favourable combination of mechanical properties including impressive high temperature fatigue, creep and environmental behaviour. Since internal grain boundaries are absent in single crystals, CMSX-4, the material of choice for many HP turbine applications, exhibits highly anisotropic mechanical properties, both in the elastic and plastic loading regimes. As such, recent research focused on the off-axis effects and multi-axial fatigue behaviour of the second generation Ni-based single crystal superalloy CMSX-4 as part of the TSB funded SAMULET programme (Strategic Affordable Manufacturing  of UK Leading Environmental Technologies), with future studies scheduled under the SILOET II (Strategic Investment in Low-carbon Engine Technology) project.

Previous research undertaken at Swansea has detailed the effect of plain and notched fatigue on Ni-based single crystal alloys orientated in <001> direction. This work focussed on CMSX-4 and two experimental alloys, exploring their LCF characteristics whilst assessing the impact of internal casting porosity on fatigue life at numerous temperatures.

Further reading:

  • W.J. Evans, R.J. Lancaster, A. Steele, M.T. Whittaker and N. Jones. “Plain and Notched Fatigue in Nickel Single Crystal Alloys”. International Journal of Fatigue 31, Issues 11-12 (2009) 1709-1718. 
  • W.J. Evans, R.J. Lancaster, A. Steele and N. Jones. “The Characterisation and Prediction of LCF Behaviour in Nickel Single Crystal Blade Alloys”. Proceedings of the Eleventh International Symposium on Superalloys September 14-18, 2008, Pennsylvania. pp 425-432.
  • Barnard  N.C., MacLachlan D.W., Jones N., Mason-Flucke J., Bagnall S.M. & Bache M.R., “Low cycle fatigue of CMSX-4 in off-axis orientations and the effect of a multi-axial stress state”, in Superalloys 2012: Proceedings of the 12th International Symposium on Superalloys, Eds. E.S. Huron, R.C. Reed, M.C. Hardy, M.J.  Mills, R.E. Montero, P.D. Portella & J. Telesman, (TMS, 2012), September 9-13, 2012, Seven Springs, PA, USA, pp. 293-300.
  • R.J. Lancaster. “The Notch Sensitivity and Crack Propagation of Fourth Generation Single Crystal Superalloys”. PhD Thesis, Swansea University 2008.

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