Materials Engineering Research

Corrosion of austenitic Fe-Ni based alloys with various chromium and aluminum additions in a carburizing-oxidizing atmosphere at 800ᐤC

Shu Liu, Yong Zhu, JunJie Cao — Wed, 17 Apr 2024 18:01:28 +0800

The corrosion behaviors of Fe-19Ni-13/21Cr-xAl (x = 0, 2, 6 at. %) alloys in a carburizing-oxidizing atmosphere were compared with those in a purely carburizing atmosphere at 800^oC. For alloys with 13 at. % Cr, 2 at. % addition of Al did not improve the corrosion resistance effectively but induced a slightly increase of the total mass gain. 6 at. % addition of Al produced a large decrease of the total mass gain, therefore the corrosion resistance was improved significantly. For alloys with 21 at. % Cr, additions of Al did not affect the total mass gain obviously. Fe-19Ni-21Cr-xAl (x = 0, 2, 6 at. %) showed similar mass gain. Increase of Cr content from 13 at. % to 21 at. % is effective for protecting the alloys from the carbon attack for Al-free alloys and alloys with 2 at. % Al. However, addition of Cr is not so helpful for alloys with 6 at. % Al. The addition of oxygen improved the corrosion resistance of all alloys significantly except the Fe-19Ni-13Cr-6Al. Pure external chromia scales on alloys without Al and with 2 at. % Al could not suppress the inward diffusion of the carbon atoms. Aluminum and chromium worked together to form mixed oxide scales inhibiting the carbon attack totally on alloys with 6 at.% Al.

Hydrocarbon fuels, combustion characteristics & insulating refractories in industrial furnace

Mahesh Borate, Prashant D. Deshmukh, Arunkumar Shetty — Thu, 21 Mar 2024 11:53:30 +0800

Liquid fuels like Furnace Oil, Light distillate oil, Diesel & gaseous fuels like PNG (Piped Natural Gas), LPG (Liquefied Petroleum Gas) are predominantly used at present in industrial applications. Single fuel, Dual fuel & Multi-fuel options are available in the market. All these fuels are called hydrocarbon fuel. A loss of drop of oil in every second can waste about 4000 liters in a year. Selection of right type of fuel depends on various factors like availability, storage, handling, Pollution & landed cost of the fuel. These different fuels used for combustion in industrial furnace are discussed herewith. Complete combustion in industrial furnace enhances efficiency, control pollution as well as global warming. Efficient use of fuel leads to complete combustion. This paper deliberates about combustion of fuel and how complete combustion is to be achieved in industrial furnace. Stoichiometric ratio ensures complete combustion. Industrial furnace uses refractories to form a combustion chamber with proper insulation to ensure temperature within the combustion chamber is as per requirement of the job. The outside skin temperature of industrial furnace is about 35ºC to 45ºC from safety point of view. To maintain this temperature difference with minimum wall thickness needs proper refractory selection which must withstand high temperature. The main objective of this research paper is to propose strategies to select the right fuel, proper insulating material to achieve complete combustion & minimum heat losses through the walls of combustion chamber. This will help in making an efficient design and optimize combustion controls to keep heat losses at minimum level.

Unveiling molecular secrets: Raman spectroscopy as a versatile tool for advanced analysis and investigation in forensic science and pharmaceuticals

Md. Dipu Ahmed, Kazi Madina Maraz, Saikot Mazumder — Tue, 05 Dec 2023 14:42:20 +0800

The conventional technologies used for identifying, investigating, and analyzing illegal drugs, explosives, and fibers in forensic science often involve destructive methods, preventing re-analysis of evidence. Conversely, a non-destructive approach is crucial for drug characterization, synthesis route development, and identification of counterfeit and adulterated pharmaceuticals. Raman spectroscopy, renowned for its rapid, non-destructive, and cost-effective nature, has emerged as the predominant technique in forensic and pharmaceutical applications. Its inelastic light scattering properties enable drug identification, minimize forensic toxicology and criminalistics, and ensure pharmaceutical product quality. This review explores the analysis of cocaine, RDX, HMX, PETN and TNT in forensic science, where Raman spectroscopy proves invaluable in detecting and quantifying drugs and explosives, deciphering synthesis routes, identifying manufacturing labs, and unveiling trafficking patterns and distribution networks. Additionally, it examines the analysis of acyclovir, ciprofloxacin, and active pharmaceutical ingredients (APIs) in the pharmaceutical industry, offering insights for quality control, combating counterfeit and adulterated products, and facilitating real-time process monitoring. Despite limitations, recent advances in data analysis techniques position Raman spectroscopy as a versatile and promising tool for sample analysis, investigation, and determination in both forensic science and pharmaceuticals, illuminating the path towards enhanced analytical capabilities in these fields.

Utilization of textile fabric waste as reinforcement for composite materials in car body applications: A review

Melese Shiferaw, Asmamaw Tegegne, Assefa Asmare — Wed, 08 Nov 2023 16:24:42 +0800

Materials are one of the basic elements or needs for continuing human beings’ life living and they are used for structural and nonstructural, biomedical, thermal, or other applications. In many types of materials, Composite materials are used in different sectors. The increasing need for eco-friendly, low-density, and lightweight product production prompted the development of fiber-reinforced polymer composites for usage in a variety of home items and automobile parts. The automobile manufacturing sectors have recently attempted to manufacture lighter and lighter parts. Shortly, automobiles must be lighter to meet demands for lower fuel usage and fewer CO₂ emissions. On the other side that textile waste is still simply thrown into a landfill in the environment resulting in and causing pollution. So, the objective of this review was to show the ability of these waste materials used as reinforcing material for composite fabrication products like car hoods, Car bumpers, and lightweight automotive parts. also, it tries to explain the roles of lightweight materials for automotive body parts and also the reduction of wastes in the textile industry by recycling and converting them into useable products, making the environment free of pollution. This waste reduction is a current world issue.

Revolutionizing energy storage: Overcoming challenges and unleashing the potential of next generation Lithium-ion battery technology

Md. Dipu Ahmed, Kazi Madina Maraz — Tue, 04 Jul 2023 17:41:06 +0800

Lithium-ion (Li-ion) batteries have become the leading energy storage technology, powering a wide range of applications in today's electrified world. This comprehensive review paper delves into the current challenges and innovative solutions driving the supercharged future of lithium-ion batteries. It scrutinizes the limitations of energy density in existing batteries, exploring advanced electrode materials and designs that promise higher capacity. Safety concerns take center stage, with a focus on cutting-edge thermal management systems and materials. The imperative of sustainable sourcing is addressed, highlighting alternative materials and recycling strategies for a greener supply chain. Transformative breakthroughs, such as solid-state electrolytes and emerging battery chemistries, offer glimpses of the future. The paper also examines the applications and market perspectives of lithium-ion batteries in electric vehicles, portable electronics, and renewable energy storage. It concludes by emphasizing the transformative potential of lithium-ion batteries in accelerating the energy revolution and paving the way for a sustainable energy future.

Load-induced local phase transformation and modulus of shape memory alloys under spherical indentation by finite element method

Sayed Ehsan Saghaian, Y. C. Lu, Sayed M. Saghaian, Haluk E. Karaca — Wed, 14 Jun 2023 10:43:25 +0800

Shape memory alloys are a unique class of materials that are capable of large reversible deformations under external stimuli such as stress or temperature. The present study examines the phase transformations and mechanical responses of NiTi and NiTiHf shape memory alloys under the loading of a spherical indenter by using a finite element model. It is found that the indentation unloading curves exhibit distinct changes in slopes due to the reversible phase transformations in the SMAs. The normalized contact stiffness (F/S²) of the SMAs varies with the indentation load (depth) as opposed to being constant for conventional single-phase materials. The load-induced phase transformation that occurred under the spherical indenter was simulated numerically. It is observed that the phase transformation phenomenon in the SMA induced by an indentation load is distinctly different from that induced by a uniaxial load. A pointed indenter produces a localized deformation, resulting in a stress (load) gradient in the specimen. As a result, the transformation of phases in SMAs induced by an indenter can only be partially completed. The overall modulus of the SMAs varies continuously with the indentation load (depth) as the average volumetric fraction of the martensite phase varies. For NiTi (E_a> E_m), the modulus decreases with the depth, while for NiTiHf (E_a< E_m), the modulus increases with the depth. The predicted young modules during indentation modeling agree well with experimental results. Finally, the phase transformation of the SMAs under the indenter is not affected by the post-yield behavior of the materials.

Polymer electrolyte design strategies for high-performance and safe lithium-ion batteries: Recent developments and future prospects

Md. Dipu Ahmed, Kazi Madina Maraz — Fri, 19 May 2023 18:33:13 +0800

Although lithium-ion batteries have gained widespread use in high-performance and mobile industries, concerns about their safety due to the low boiling point of their organic liquid electrolyte have posed challenges to their further development. In response, solid polymer electrolytes have emerged as a promising alternative, characterized by low flammability, flexibility, and high safety relative to liquid electrolytes. However, commercialization has been hindered by limitations in Li-ion conductivity and mechanical properties. Recent research efforts have focused on addressing these limitations to improve the performance and safety of polymer-based Li-ion batteries. This review discusses the utilization of polymer materials to enhance battery safety and overcome previous challenges, with a particular emphasis on the design of robust artificial interfaces to increase battery stability. Furthermore, we discuss the prospects for the future of polymer-based battery industries.

Residual properties of silicone (MED-4719) lead with leads from retrieved devices

Anmar Salih, Tarun Goswami — Tue, 08 Nov 2022 15:44:22 +0800

Leads are designed for in vivo applications, however, for a definite period of time. In-vivo environment affects the mechanical behavior of implantable devices, therefore, there is a need to evaluate the residual properties of implantable leads used with pacemakers, defibrillator and neuro-stimulators. Silicone (MED-4719) lead is widely used in cardiac implantable electronic devices made by different manufacturers. . We collected 150 devices (with or without leads) from Anatomical Gift Program of the Wright State University. The objective of this study was to investigate the residual properties of Silicone (MED-4719) lead with different in vivo exposure time and compare the properties of a new, unused lead supplied by Medtronic for the purposes of this research. The tensile test was performed by applying specific load on the samples, percentage elongation at 5N and the corresponding displacement measured. Load to failure, percentage elongation, ultimate tensile strength, and modulus of elasticity were determined for each lead. Methods to collect and compile data were standardized, and statistical models were used to assess the sensitivity of measured parameters with in vivo performance. Load to failure, elongation to failure, ultimate tensile strength, and percentage elongation at 5N showed a significant decrease after 94 months (P = 0.0063), 8 months (P = 0.0136), 94 months (P = 0.0244) and 71 months (P-value = 0.0326) after implantation, respectively. On the other hand, modulus of elasticity was found proportional to the number of months device was exposed and showed significant increase after 71 months (P = 0.0446) of in-vivo environment.

Degradation mechanisms of zinc-air batteries used in hearing aid

Kelly Hunt, Mallory Bates, Gerard Klint Simon, Tarun Goswami — Wed, 25 May 2022 17:20:40 +0800

Hearing aid devices are powered by the oxidation of zinc that occurs within zinc-air batteries. Zinc-air batteries have an average discharge time of 7 days. Therefore, hearing-aid devices need frequent battery replacement. In this paper, degradation mechanisms of zinc-air batteries investigated where a competition mechanism between zinc passivation and dendritic formation dictates the battery life. This research included exposure time from none to 9 days and to document dendritic growth with time. Scanning electron microscope images were taken to quantify the damage growth as well energy dispersive X-ray tests were conducted to comment on the composition changes. The results confirmed an increase in oxygen in exposed batteries from unexposed. These results matched findings from past literature. Exposure time was investigated to optimize battery lifespan. In conclusion, life of zinc-air batteries depends on the competition mechanism of zinc passivation and dendritic formation caused by oxidation and our investigation shows that this occurs within the first 7 days.

Comparison of aero engine component lifing methods

Ashley Whitney-Rawls, Paul Copp, Jace Carter, Tarun Goswami — Mon, 23 May 2022 20:19:09 +0800

Failure of critical engine components such as compressor, fan, and turbine disks during flight can cause the loss of the engine, aircraft, or even life. To reduce the risk of this failure during flight, different methodologies and tools have been developed to determine the safe operating life of these critical disk components. The two most widely used lifing methods, safe-life and damage tolerance, are inherently conservative, retiring all components when a predetermined operating limit is reached. Both methods retire components with theoretical useful life remaining. Additional lifing methods can be used to reduce this conservatism and extend the life of these components. Retirement for cause, developed within the United States Air Force is a lifing method that can extend the life of components by retiring a component only when there is cause to do so. Military and industry standards on lifing methodologies were reviewed. Both deterministic and probabilistic approaches to disk lifing methods are discussed as well as current tools. This paper provides a comparison of the methodologies and tools currently being used today by both the government and industry.