Additive Manufacture

During the first part of MMTECH, gamma titanium aluminide powders were developed by partner MBN. These wil be turned into near-net parts using blown powder systems at USFD and PRIMA.

A set of test-articles was defined and included blocks for microscopy and tensile specimens as well as a standard features part which incorporates the most critical geometrical features and tolerances required by the end-users.

The size and morphology of the different powders developed by MBN were characterised and compared with gas-atomised Ti-6Al-4V. Early results led to a refinement of the powder sieving stage. A set of test builds were made based around parameters found in the literature. As expected, these exhibited cracking and porosity, with higher laser powers inducing greater cracking and porosity.

Non-porous, crack-free parts were produced by defocussing the laser; unfortunately, this limited build times to 10 minutes before filters became clogged and oxygen levels rose to unacceptable levels.

Further work with heated powder-bed systems was carried out, but it was not possible to create crack-free parts on these systems as they could not reach sufficiently high temperatures.

PRIMA developed an optimsed deposition head for the machine developed in the BOREALIS project. This has 3D capability, new powder feed nozzles and a second, high-powered laser.

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