Modelling and Validation of Linear friction welding of Ti-6Al-4V for aeroengine application

Schrӧder, Florian (2013). Modelling and Validation of Linear friction welding of Ti-6Al-4V for aeroengine application. University of Birmingham. Ph.D.

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Abstract

Linear friction welding (LFW) is a solid state joining process which - if implemented successfully - allows for significant weight savings in modern aero-engines with subsequent benefits such as increased performance, fuel economy and reduced CO2 emissions. Weight reductions are achieved by joining blades and discs forming an integrally bladed disc known as a blisk.

In this dissertation a finite element model is presented, which simulates the LFW process, specifically the formation of thermal profiles, upset rates, flash morphologies and in-plane forces. Experimental trial studies investigating heat generation, process parameters and weld-interface geometries were conducted using a laboratory scale LFW apparatus to (i) validate models and (ii) improve understanding of the process. It was used in conjunction with high speed photography to study the mechanisms by which material is extruded and the ash is formed. A criterion is proposed that allows predicting its morphology. The model was validated against a wide range of key process parameters (frequency, amplitude, pressure) and shown to be in good agreement with experimental data. Main focus lies on joining of the titanium alloy Ti-6Al-4V due to its industrial relevance, but joints applying dissimilar materials (Ti-6Al-4V - Ti-6Al-2Sn-4Zn-6Mo) are also investigated.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):