Laser Engineering Net Shaping Method in the Area of Development of Functionally Graded Materials (FGMs) for Aero Engine Applications - A Review

Modern aero engine components are subjected to extreme conditions were high wear rate, excessive fatigue cycles, and severe thermal attack are inevitable. These aggressive conditions reduce the service life of components. Its generic effect is magnified in the light of understanding the fact that aero engine parts are highly sensitive to functional and dimensional precision; therefore, repair and replacement are great factors that promote downtime during operation. Hard thermal barrier coatings have been used in recent times due to their optimized properties for maximum load bearing proficiency with high temperature capability to meet performance and durability required. Nevertheless, less emphasis is being given to the coating-substrate interaction. Functionally graded structures have better synergy and flexibility in composition than coatings, giving rise to controlled microstructure and improved properties in withstanding acute state of affairs. Such materials can be fabricated using Laser Engineered Net Shaping (LENS™), a laser-based additive manufacturing technique. LENS™ offers a great deal in rapid prototyping, repair, and fabrication of three-dimensional dense structures with superior properties in comparison with traditionally fabricated structures. The manufacture of aero engine components with functionally graded materials, using LENS™, can absolutely mitigate the nuisance of buy-to-fly ratio, lost time in repair and maintenance, and maximize controlled dimension and multi-geometric properties, enhanced wear resistance, and high temperature strength. This review presents an extensive contribution in terms of insightful understanding of processing parameters and their interactions on fabrication of functionally graded stainless steel, which definitely influence the final product quality

Parametric Variables in Electro-deposition of Composite Coatings

Nowadays, synergy of the attractive properties of materials while avoiding limitations of their use in isolation is a major driver for flexibility in design and manufacture. This allows tailoring of materials’ properties to meet specifications. Composite technology utilizes an excellent combination of properties: strength, stiffness, light weight, wear, chemical, corrosion, and temperature resistance, which transcend those of the constituent materials. Engineering structures, equipment, and vessels in key industries that are material-dependent are susceptible to deterioration process and damage over time in their service conditions. Composite coatings through electro-deposition offer a reliable cost-effective means of impacting special surface properties for corrosion protection, better appearance, and mechanical properties’ enhancement. The properties of the composite coatings can be optimized by varying the type, size, amount and distribution of the particles content incorporated among others

Electrodeposition of Functional Coatings on Bipolar Plates for Fuel Cell Applications – A Review

The issue of corrosion and degradation has been evaluated as one of the major sources of concern in the history and trend of materials development and their applications in engineering. Design, process, and production consideration of materials hinge on the motive of built-to-last technology in their lifetime applications. The “World Corrosion Organization” has calculated that the direct cost of corrosion worldwide is over 3% of global gross domestic product (GDP)—approximately US$2.2 trillion—every year

Effect Of Insecurity Of Security Officers On Nigeria Economic Prospect

This study examined the effect of insecurity of security officers on economic prospect in Nigeria. This work seeks to explain the meaning of security, insecurity, types of security, causes of insecurity of security officers and its effect on Nigeria economic prospect. The security officials in which  their statutory assignments are to secure life and properties of the citizens and aliens are to be firstly safe in order to discharge their duties diligently. Therefore a random sampling through distribution of 130 questionnaire to respondents. Also, secondary data such as relevant books, news papers, research articles and government publications in Nigeria were adopted. After the data analysis conducted, the findings testified that insecurity of security officials is evident in Nigeria as a result of many identified factors responsible for their insecurity which hindered Nigeria economic prospect as a result of discouragement cause to both existing and prospective investors locally and internationally, it also led to displacement of investors from crisis zone to peaceful area, sometimes led to relocation of industry to security assured country. After rigorous findings, this research concludes and recommended that, the government, civil society and every arms of the society must take a proactive approach to ensure that the safety of every security officials in Nigeria is given needed attention in order to address the issue

Computatonal Analysis of System and Design Parameters of Electrodeposition for Marine Applications

The financial prudence of the global world is shaken due to the vigor induced by corrosion as the degradation of essential assets, namely, oil and gas platforms and marine machineries, appears as a red-flagged situation. The exacerbation created by chemical degradation of these assets is as a result of the presence of saltwater, and the highly dominating activity of salt in the atmosphere poses a critical influence in selecting the mode of corrosion prevention to be integrated. As the hunger for longer term service and cost effectiveness of protection increases, studies are clustered in the search of new corrosion-resistant coatings while adhering to the increasing stringent environmental code of practice. Porosity is a key factor which is considered in the development of corrosion-resistant coatings, stimulating localized forms of corrosion, such as galvanic and crevice corrosion. Nevertheless, researches have been implemented to coin this challenge by acquiring full understanding of effective parameters of salt bath conditions, their interactions, and influence on the degree of uniform electrodeposition. A significant contribution is presented in the light of reviewing the possibility of computational analysis of system and design parameters in optimizing the deposition rate and quality

Laser Surface Modification — A Focus on the Wear Degradation of Titanium Alloy

Over the years, engineering materials are being developed due to the need for better service performance. Wear, a common phenomenon in applications requiring surface interaction, leads to catastrophic failure of materials in the industry. Hence, preventing this form of degradation requires the selection of an appropriate surface modification technique. Laser surface modification techniques have been established by researchers to improve mechanical and tribological properties of materials. In this chapter, adequate knowledge about laser surface cladding and its processing parameters coupled with the oxidation, wear and corrosion performances of laser-modified titanium has been reviewed

Spark Plasma Sintered High-Entropy Alloys: An Advanced Material for Aerospace Applications

High-entropy alloys (HEAs) are materials of high property profiles with enhanced strength-to-weight ratios and high temperature-stress-fatigue capability as well as strong oxidation resistance strength. HEAs are multi-powder-based materials whose microstructural and mechanical properties rely strongly on stoichiometry combination of powders as well as the consolidation techniques. Spark plasma sintering (SPS) has a notable processing edge in processing HEAs due to its fast heating schedule at relatively lower temperature and short sintering time. Therefore, major challenges such as grain growth, porosity, and cracking normally encountered in conventional consolidation like casting are bypassed to produce HEAs with good densification. SPS parameters such as heating rate, temperature, pressure, and holding time can be utilized as design criteria in software like Minitab during design of experiment (DOE) to select a wide range of values at which the HEAs may be produced as well as to model the output data collected from mechanical characterization. In addition to this, the temperature-stress-fatigue response of developed HEAs can be analyzed using finite element analysis (FEA) to have an in-depth understanding of the detail of inter-atomic interactions that inform the inherent material properties

Economic and environmental assessment of electricity generation using biogas and heat energy from municipal solid waste: A case study of Lesotho

This study examined the potential of electricity generation from biogas and heat energy arising from municipal solid waste (MSW) collected from the year 2021 to 2045 using anaerobic digestion (AD) and incineration (INC) technologies. The goal of this paper is to evaluate the economic and environmental benefits of implementing the aforementioned technologies in Lesotho. The environmental impact was assessed by using the life cycle assessment strategy based on global warming potential for three scenarios, while the economic assessment was carried out by using the net present value (NPV), levelized cost of energy (LCOE) and total life cycle cost. The key findings show that, over 25 years (2021–2045), MSW generation will range from 185.855 to 513.587 kilotons. The methane yield for the duration of the project for AD technology is 44.67–126.56 thousand cubic meters per year. Moreover, the electricity generation will range from 0.336–0.887 GWh for AD technology and 17.15–45.34 GWh for INC technology. Economically, the results demonstrated that the two waste-to-energy technologies are viable, as evidenced by their positive NPV. The NPV for AD was about USD 0.514 million, and that for INC technology was USD 339.65 million. AD and INC have LCOEs of 0.029 and 0.0023 USD/kWh, respectively. The findings demonstrate that AD can minimize the potential for global warming by 95%, signifying a huge environmental advantage. This paper serves to provide the government, as well as the investors, with current and trustworthy information on waste-to-energy technologies in terms of costs, execution and worldwide effect, which could aid optimal decision-making in waste-to-energy projects in Lesotho