In the frame of additive manufacturing of metals, laser powder-bed fusion is investigated in this paper as an advanced industrial prototyping tool to manufacture Inconel 718 turbine blades at a predesign stage before flow production. Expediting of the evaluation of any upgrade to the part is aimed. To this purpose, possible anisotropy of manufacturing is preliminarily investigated via tensile testing at room and elevated temperature as a function of the sloping angle with the building plate; the normalized strength is given and compared with similar studies in the literature. Positioning and proper supporting in manufacturing are discussed; the parts are further investigated to assess their compliance with the intended nominal geometry.

Titanium alloys are employed for several applications, ranging from aerospace to medicine. In particular, Ti-6Al-4V is the most common, thanks to an excellent combination of low density, high specific strength and corrosion resistance. Laser welding has been increasingly considered as an alternative to traditional techniques to join titanium alloys. An increase in penetration depth and a reduction of possible welding defects is achieved indeed; moreover a smaller grain size in the fused zone is benefited in comparison to either TIG and plasma arc welding, thus providing an increase in the tensile strength of the welded structures. The aim of this work is to develop the regression model for a number of responses which are crucial for the feature of the joint. The study was carried out on 3 mm thick Ti-6Al-4V plates; a square butt welding configuration was considered employing a disk-laser source. A 3-level factorial plan was hence arranged in a face-centred cubic scheme. The responses were analyzed referring to the governing parameters. Then, an optimization was carried out via statistical tools, in order to find the optimal welding set-up for the alloy under examination.

Titanium alloys are employed in a wide range of applications, from aerospace to medicine. In particular, TÍ-6AI-4 V is the most common, thanks to an excellent combination of low density, high specific strength, and corrosion resistance. Laser welding has been increasingly considered as an alternative to traditional techniques to join titanium alloys. An increase in penetration depth and a reduction of possible welding defects are indeed achieved: moreover, a smaller grain size in the fused zone (FZ) is benefited in comparison to either tungsten inert gas (TIG) or plasma arc welding, thus improving the tensile strength of the welded structures. This study was carried out on 3 mm thick TÍ-6AI-4 V plates in square butt welding configuration. The novelty element of the investigation is the use of a disk-laser source, which allows a number of benefits thanks to better beam quality: furthermore, a proper device was developed for bead protection, as titanium is prone to oxidation when infused state. A three-level factorial plan was arranged in facecentered cubic scheme. The regression models were found for a number of crucial responses and the corresponding surfaces were discussed: then a numerical optimization was carried out. The suggested condition was evaluated to compare the actual responses to the predicted values; X-ray inspections, Vickers micro hardness tests, and tensile tests werepeiformedfor the optimum.

Titanium and its alloys are increasingly being used in aerospace, although a number of issues must be addressed. Namely, in the framework of welding to produce complex parts, the same mechanical strength and a reduced buy-to-fly ratio are desired in comparison with the same components resulting from machining. To give grounds to actual application of autogenous laser beam welding, Ti-6Al-4V L-and T-joints have been investigated in this paper, as they are a common occurrence in general complex components. Discussions in terms of possible imperfections, microstructure, and microhardness have been conducted. Then, a real part consisting of a support flange for aerospace application has been chosen as a valuable test-article to be compared with its machined counterpart both in terms of strength and buy-to-fly. The feasibility and the effectiveness of the process are shown.

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