Browsing by Author "Wang, Fude"
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Item Open Access Morphology investigation on direct current pulsed gas tungsten arc welded additive layer manufactured Ti6Al4V alloy(Springer Science Business Media, 2011-11-30T00:00:00Z) Wang, Fude; Williams, Stewart W.; Rush, M. T.The effects of pulsed gas tungsten arc weldingparameters on the morphology of additive layer manufacturedTi6Al4V has been investigated in this study. Thepeak/ base current ratio and pulse frequency are found tohave no significant effect on the refinement of prior betagrain size. However, it is found that the wire feed ratehas a considerable effect on the prior beta grainrefinement at a given heat input. This is due to the extrawire input being able to supply many heterogeneousnucleation sites and also results in a negative temperaturegradient in the front of the liquidus which blocks thecolumnar growth and changes the columnar growth toequiaixal growth.Item Open Access Wire and arc addictive manufacture (WAAM) reusable tooling investigation(Cranfield University, 2013-10) Yan, Lihao; Mehnen, Jorn; Wang, FudeComposite materials have been extensively adopted by modern aircraft design and manufacture. This manufacturing process needs a forming mould. Invar alloy has been widely used to manufacture moulds for the fabrication of aeronautics and astronautics composite structures because of its unique low thermal expansion coefficient. However, Invar is very expensive and the machining and repair process is difficult and costly. Therefore, to find an alternative approach to manufacture and repair the Invar mould is would help to save costs. Additive Manufacturing (AM) technology is an innovative technology which can manufacture components layer upon layer directly from a CAD file without the need of tooling. Unlike conventional machining technologies which remove materials from a solid block of metal, AM is an additive process which can significantly save materials. Dissimilar material components can be fabricated by Wire and Arc Additive Manufacturing (WAAM) process with good metallurgical joints. A new, functional tooling approach combining Invar and steel using Wire and Arc Additive Manufacturing (WAAM) technology is introduced in this research. Invar is used to fabricate the top part of the tool as it has a uniquely low thermal expansion coefficient property while the base part of the tool is made of mild steel to supply strength and save costs. The research showed that Invar can be successfully deposited on steel using the WAAM process with high integrity joint. In addition, an FEM model was built to simulate the deformation of multi-material moulds in the autoclave heating process. Following on from the results from the FEA-based mould’s deformation prediction, a parameter compensation method was proposed for the bi-material mould design and optimisation. The FEM model was verified through a case study around a composite door from a commercial aeroplane. The results indicate that the mould deformation can be effectively controlled by parameter compensation and the optimised mould will satisfy industrial tolerance requirements.