The implementation of A.M processes in manufacturing is sustainable since it provides higher efficiencies, accuracy and minimal material waste compared to conventional manufacturing methodologies. A.M technologies have a great potential to bring a radical dynamic shift in the fabrics of society, so much so that its emergence in the manufacturing sector renders conventional manufacturing techniques obsolete.

The investigation focused on studying how the reinforcement powders and titanium alloy substrate were influenced by the volumetric energy which was absorbed. The only processing parameters which were varied was the laser intensity and the scanning speed, which were employed to design the direct laser metal deposition (DLMD) single- and multi-tracks. Laser surface modification techniques has unique benefits and properties compared to other conventional techniques. These techniques have process factors that affect directly the microstructure of materials which in turn influence the materials properties. The results revealed dense microstructure in the fabricated coatings in terms of the microstructural evolution, the sizes of the different grains, the structure of the phases formed and the orientation. The modified surface layer of the additively manufactured coating had improved and had a fine microstructure. Optimizing the DLMD processing conditions resulted in a crack-free surface layer but still promoted a few population of gas defects. Morphological observations along the side of the surface showed the prominence of the adhesive powder, flow path of the melt pool and the areas which overlapped, attributed to the increase of the laser scanning speed. When the laser scanning speed was increased it attributed to the grain width reduction of the prior beta and a transformation in shape of the martensitic primary alpha into fine needle-like structures. In terms of the yield and tensile performance, the results revealed that increasing the scan velocity was favourable to the property, showing that the mechanical performance became better at higher scanning speeds. The microstructural and mechanical properties were ascertained and the relationships with the process parameters were achieved. Their results indicated that slow traverse speeds increase the scale of columnar grains, while other process parameters were kept constant. Higher laser powers and slower traverse speeds results in the increase in size of the α and β laths. Detailing what was found, when the traverse speed was increased, it resulted in the columnar grains to become longer and finer due to decreased laser energy density to the previously deposited layer, therefore the thickness of the layers was decreased. 


Microstructural Enhancement and Performance of Additive Manufactured Titanium Alloy Grade 5 Composite Coatings

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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