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Nickel-based alloys have been considered as candidate structural materials used in generation IV nuclear reactors serving at high temperatures. In the present study, alloy 617 was irradiated with 180-keV helium ions to a fluence of 3.6 × 1017 ions/cm2 at room temperature. Throughout the cross-section transmission electron microscopy (TEM) image, numerous over-pressurized helium bubbles in spherical shape are observed with the actual concentration profile a little deeper than the SRIM predicted result. Post-implantation annealing was conducted at 700 °C for 2 h to investigate the bubble evolution. The long-range migration of helium bubbles occurred during the annealing process, which makes the bubbles of the peak region transform into a faceted shape as well. Then the coarsening mechanism of helium bubbles at different depths is discussed and related to the migration and coalescence (MC) mechanism. With the diffusion of nickel atoms slowed down by the alloy elements, the migration and coalescence of bubbles are suppressed in alloy 617, leading to a better helium irradiation resistance.

P/M Ti-Al-Mo-V-Ta alpha-beta alloys were processed by hot-pressing sintering technique. The effects of Ta additions on microstructure and properties of the Ti-5Al-4Mo-4V alloys were investigated using X-ray diffraction, optical microscope, scanning electron microscope and mechanical properties tests. The results show that minor Ta addition improves the relative density and the mechanical properties of P/M Ti-5Al-4Mo-4V alloys. After sintering for 4h at 1623 K, the relative density and compression strength of Ti-5Al-4Mo-4V-5Ta alloy are 99.3% and 1950 MPa.

Laser additive manufacturing techniques are demonstrated in two case studies to be able to produce aerospace components which meet all technical requirements whilst the cost of production is halves compared to conventional manufacturing routes.

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