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Craig Knowles

This project is supervised by Professor RB Tait and funded by the CSIR. A relatively new manufacturing technique called Selective Laser Sintering (SLS) has been developed for use with metals (Direct Metal Laser Sintering - DMLS) with the ability to manufacture extremely complex parts from a metallic powder.

The laser sinters/melts the powder in successive cross-sections and in this way, the components are built layer-by-layer with very high densities (approaching 100%). Aircraft turbine blades have very complex geometries and the possibility of Selective Laser Melting/Sintering as a manufacturing method would greatly reduce the costs associated with aircraft engine construction. DMLS has the capability of sintering Ti-6Al-4V powder which is an alloy used in some aircraft gas turbine engines.

One of the greatest concerns in aircraft turbine design is High Cycle Fatigue (HCF) since a crack would propagate through a turbine blade very fast due to the ultra-high rotation speed. The objective of this thesis is to determine the fatigue threshold of SLM manufactured Ti-6Al-4V and any residual stress properties with the intention for use in an aircraft gas turbine.