Showing papers by "Olawale S. Fatoba published in 2020"

Advances in manufacturing analysis: fractal theory in modern manufacturing

Abstract: A review of the applications of fractal theory in modern manufacturing is presented in this chapter. A brief conceptual foundation, typical examples, and methods of computing fractals are summarized. The most common methods of computing fractal dimensions include box-counting, area-based measurements, and fractional Brownian motion (fBm) methods and have been briefly discussed along with the proposed improvements in the literature. It is noted that there are concerted efforts to improve on the known methods to enhance their accuracy and application in various fields. Finally, applications of fractals in thin films, laser processing, machining, and friction stir processes/welding are illustrated based on the published data. It is derived that fractal analysis is important in (1) understanding the growth of structures during different manufacturing processes (and parameters) and (2) developing fractal-like structures for enhanced performance in various engineering applications. Directions for future research and applications of fractal theory in manufacturing and their potentials are described in respective sections of the chapter. The chapter is a useful resource for academic and industry in studying, developing, and manufacturing of fractal-like engineering components and the interrelationships among the manufacturing process, parameters, and fractal characteristics of the engineering product.

Numerical modelling and microstructural evolution of hybrid Ti-6Al-4V/Ti-Al-Si-Cu composite coating

Abstract: Additive manufacturing is a commercially competitive manufacturing technique with the possibility of altering the entire perception of design and fabrication It offers suitable capabilities for the building and repairing applications in the aerospace industry, which usually requires high level of accuracy and customization of parts which usually use materials known to pose difficulties in fabrication such as titanium alloys The major factors that determine the formation of the dendritic structure are the thermal gradients within the substrate during cooling and the cooling rates The rapid cooling and input of heat locally during the laser deposition process resulted in metallurgical modifications such as the formation of a complete martensitic structure, a mixture of columnar grains and layer of bands During the deposition process, the metal solidified, and the developed model enabled predictability of microstructural development and the sizes of the grain growth The 3D numerical investigation provided clarification and had substantial effects in the prediction of the overall resulting molten pool size and geometry size

Effect of Process Parameters on the Hardness Property of Laser Metal Deposited Al–Cu–Ti Coatings on Ti–6Al–4V Alloy

Abstract: The aim of this investigation is to characterize the effect of process parameters applied to the laser metal deposition of Al–Cu–Ti coatings on titanium substrate (Ti–6Al–4V). After the deposition process was completed, a new hybrid coated surface emerged with improvements in the following areas: improved thermal, mechanical, and metallurgical properties. During the laser metal deposition procedure to obtain a hybrid coating on Ti–6Al–4V, certain process parameters were employed to achieve the optimum results which are the scanning speed (1.0 m/min) and the laser power of the procedure, which was varied between 900 and 1000 W. The microstructural analysis was carried out using the scanning electron microscope (SEM) and an optical microscope (OPM). The mechanical properties of the samples were characterized using microhardness test.

Study of Additive Manufactured Ti–Al–Si–Cu/Ti–6Al–4V Composite Coating by Direct Laser Metal Deposition (DLMD) Technique

Abstract: Direct laser metal deposition (DLMD) is an additive manufacturing technique that is favourable in industries such as aerospace, biomedical, sports and automotive. Its advanced three-dimensional printing via layer-by-layer additive of a material allows for high-dimensional accuracy of the manufacturing of a part, but the surface finishing is still a limitation for the technology. Complex geometrical parts can be manufactured or repaired by employing the technology. This study focuses on the DLMD of Ti–Al–Si–Cu-based composite coatings on Ti–6Al–4V substrate, with the processing parameters such as the laser power and scanning speed being varied, while the other parameters were invariant. The microstructural evolution was analysed, and its influence on the anisotropy of the mechanical properties, the hardness property, and the corrosion performance of the material was investigated. The results showed that at low laser power and scan speed of 900 W and 1.0 m/min of Ti–Al–13Si–6Cu, which had the highest addition of alloying content, the highest hardness and improvement on the substrate was achieved. Large intermetallics compounds were formed of which the grains varied between columnar and backbone-like structures. The composite coating with the best corrosion rate was Ti–Al–7Si–Cu at 1.305 × 10−3 mm/year.

Laser Metal Deposition of Titanium Composites: A Review

Abstract: Composite materials are used for the manufacturing of light weight components and structures in many industries. Composite materials are obtained by combining materials with preferred properties and by synthesizing a new material using two or more materials having the desired properties. The composite material obtained has an enhanced proportion of the desired property of each of the constituent materials. Titanium alloy has been modified by adding another material to it to form titanium composites. Its properties make it suitable for most applications where low density and good corrosion resistance is necessary such as in turbine engine components, high-performance automotive parts, aircraft structural components, marine applications, aerospace fasteners, medical devices, biomedical applications (implant and prostheses) and sport equipment. Titanium composites are often used for surface modification to improve certain mechanical properties. The efficient fabrication of these composite materials is a significant challenge faced by manufacturers. The advent of additive manufacturing technology made it easier to fabricate composite materials like titanium. Laser metal deposition, an additive manufacturing process, is a process that offers excellent opportunities in fabrication of titanium and its composites. This process also helps to fabricate complex and innovative parts which cannot be effectively manufactured using substantial manufacturing process. This paper provides an overview of laser metal deposition processes used for fabricating titanium composites.

Experimental Investigation of Laser Metal Deposited Al–Cu–Ti Coatings on Ti–6Al–4V Alloy

Abstract: The aim of this research is to study the effect of aluminum-based coatings on the new emerging surface properties, producing improved thermal, mechanical, tribological and metallurgical properties, which can withstand adverse environmental conditions using laser metal deposition technique. In this study, laser metal deposition was used to produce a hybrid coating on Ti–6Al–4V at a scanning speed of 0.8 m/min. The laser power of the process was also varied between 900 and 1000 W. The microstructure was characterized by using the scanning electron microscope (SEM) and an optical microscope (OPM). The mechanical properties of the samples were characterized using microhardness test. From the results, the higher the scanning speed, the more the microhardness of the samples.