Adhesively bonded joints offer a superior alternative to traditional mechanical fasteners, providing uniform stress distribution, reduced weight, and the ability to join dissimilar materials. Their versatility makes them indispensable across the aerospace, automotive, and medical industries. However, performance is highly dependent on adhesive selection, surface preparation, and environmental resilience. This study provides a comprehensive critique of failure modes, including interfacial, cohesive, and mixed-mode damage, often triggered by temperature fluctuations or cyclic loading. It further examines standardized testing protocols under ASTM, ISO, SAE, and EN frameworks, such as lap shear and fatigue testing, to ensure structural reliability. A significant portion of the research focuses on sustainability, addressing the challenges of toxicity and recyclability through bio-based materials and reversible bonding. Finally, the study explores emerging innovations like self-healing polymers and AI-assisted selection, which are set to revolutionize the future of adhesive technology. By balancing structural efficiency with environmental considerations, adhesively bonded joints remain a cornerstone of modern engineering.

Ballistics, the science of projectile motion, encompasses the study of objects such as bullets, missiles, and rockets from launch to impact, divided into internal, external, terminal, and forensic ballistics. This paper explores recent advancements in ballistic materials, methods, and sustainability challenges. Traditional and self-healing materials, including microcapsule-based, bio-inspired, and metallic self-repairing systems, are examined for their applications in armor, projectiles, and thermal protection. Experimental techniques like light gas guns and high-speed photography, alongside numerical simulations such as finite element analysis (FEA) and smoothed particle hydrodynamics (SPH), are compared for their efficacy in ballistic research. High-velocity projectiles exceeding Mach 5, including hypersonic and kinetic energy penetrators, are analyzed for their aerodynamic and material challenges, with future directions pointing toward AI-guided systems and 3D-printed materials. The study also highlights green ammunition innovations, such as lead-free bullets and biodegradable cartridges, to address environmental concerns like toxic propellants and heavy metal contamination. Sustainability efforts focus on resource efficiency, including recycled composites and additive manufacturing, while military and civilian applications explore hypersonic swarms and non-lethal munitions. The paper concludes with future perspectives, emphasizing digital twins in forensics, space ballistics, and closed-loop ammunition recycling. By integrating experimental and computational approaches, this research aims to advance ballistic technologies while addressing ecological and ethical challenges in the field.

Sustainable composite materials represent a critical step towards a more environmentally friendly future. They are an alternative to traditional composites by reducing waste. Sustainability of materials can be achieved through various studies. Composite materials will become more efficient and environmentally friendly with the various findings of researchers. They will play an important role in overcoming challenges such as resource scarcity. Sustainable composites significantly decrease environmental problems related to the production of biodegradable engineered materials. The production of sustainable composites results in less energy consumption and lower toxic gases. Sustainable composites are used in packaging, construction, automobiles, sports, and furniture equipment. In this study, sustainable composite materials are examined and criticized considering their benefits, innovations, applications and challenges, and future perspectives.

Purpose This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying mediums and conditions, including dry sliding, distilled water and seawater lubrication, to determine their suitability for high-stress applications. Design/methodology/approach Tribological tests were conducted using a pin-on-disc setup with AISI 316 L stainless steel (SS) as counterface. Experiments were carried out under loads of 150 and 300 N and sliding speeds of 1.5 and 3.0 m/s. Values of temperatures, friction coefficients and wear rates were recorded to analyze the effect of fillers and lubrication mediums. Findings The PAI composite outperformed the neat PAI under all conditions, showing significant reductions in friction coefficients and wear rates. Seawater lubrication yielded the best results, achieving friction coefficients of 0.05 and 0.01 and specific wear rates of 18.10−16 m²/N and 1.10 −15 m²/N, for neat PAI and PAI composite, respectively. Graphite and PTFE fillers enhanced lubrication, reduced surface temperatures and mitigated abrasive and adhesive wear mechanisms. Superior cooling and lubrication effects of the seawater contributed to these improvements. Originality/value Previous studies mainly focused on dry sliding and distilled water lubrication for the PAI and its composites, with no research on the seawater conditions. This study compares the tribological behaviors of the neat PAI and PAI composite against AISI 316 L SS under dry sliding, distilled water and seawater lubrication. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0302/

Materials obtained from nature are divided into two groups: natural and artificial. Materials fall into four main categories: metals, ceramics, polymers, and composites. Glass is a solid material that is transparent, usually rigid, fragile, and has an inorganic amorphous structure that allows the preservation of liquids. Ceramics, on the other hand, are solid materials containing metal and non-metal inorganic compounds with ionic or covalent bonds. Nontechnical ceramics fall into three general groups: cement and concrete, fired clay, minerals, and stone. Fibers and particles are utilized as strengthening constituents in different types of composite materials. Hybrids can be used as different types of composite materials and thermal insulation parts. Hybrid materials are divided into four groups: composites, foams, honeycombs, and natural materials. Composites and foams can be made from metallic, ceramic, or polymer-based matrices. Metals and their alloys are materials connected by metallic bonds. Metals are divided into two groups: ferrous and non-ferrous. A polymer is a substance comprised of enormous molecules. Polymers have larger molecular masses than small molecule compounds. Polymers are materials connected by covalent bonds and dominant van der Waals bonds. Polymeric materials are divided into two groups: elastomers and plastics. Plastics (polymers) are divided into two main parts: thermoplastics and thermosets. Thermoplastics can be reused when heated due to their weak bonds, meaning they are suitable for recycling. A thermoset is a thermosetting polymer and is a material attained by permanently hardening the resin. Industrial usage areas of polymers include textiles, electronic goods, the automotive industry, healthcare, building materials, and food. In this study, polymeric materials were defined, then classified and their usage areas were criticized.

This study explores the explosive welding of titanium (Grade 2 Ti) and aluminum (Al5083–H111) alloys at varying detonation ratios (R = 1.5, 2, 2.5, 3). Following the welding process, mechanical and metallurgical tests, including micro hardness, tensile-shear, and bending tests, were conducted, and performance was assessed through SEM imaging for microstructural analysis. Ballistic tests were also performed to evaluate the suitability of the welded materials for specific operational conditions. The explosive welding process induces high-velocity impact, causing mechanical interlocking at the interface. As the detonation ratio increases, the interface waviness and mechanical bonding improve. At R = 3, significant increases in hardness were observed in both the titanium and aluminum plates. Tensile-shear tests showed no fractures or separations at the bonding interfaces, with titanium's tensile strength increasing as the detonation ratio rose. No intermetallic formation occurred, and the wavy interface ensured mechanical interlocking. Bending tests revealed no failures, demonstrating the process's reliability. Microstructural analysis confirmed the absence of intermetallics, and all tests met ASTM A 263-94a standards. In conclusion, with appropriate detonation ratios and parameters, titanium-aluminum joints can be effectively and reliably produced through explosive welding.

In recent years, forensic engineering, a growing field of engineering, has developed. If the product malfunctions prematurely, the user will not be able to use that product, and sometimes it may lead to personal injuries. Sophisticated techniques such as SEM and DSC are used to study these problems. Forensic engineers evaluate documentary evidence so that the court can make the right decision. In this study, forensic materials and test methods are discussed. For this purpose, first, the concept of Forensic Engineering was introduced and the defects occurring in the products were examined. Then, in case of a dispute between the parties, it is explained how forensic engineers examine the products and prepare an expert report to resolve the dispute. Finally, how and with which devices macroscopic and microscopic tests, mechanical and thermal tests were performed were examined.

In this study, we developed and implemented a cost-reducing, real-time virtual welding simulator to train welder candidates. In order to make a real-time welding simulation, a three-dimensional weld bead form was designed. We used a parabola as the basic bead slice shape, considering the similarity between the parabola and the bead slice. During the welding process, the parameters of the weld bead shape are calculated at each time step using an artificial neural network. This network determines the shape of the weld bead and the depth of penetration, based on inputs received from the sensor device that tracks the motions of the torch. After the parabola’s parameters have been determined, the voxel map and corresponding hash-based octree data structure are generated in real-time. By using the voxelized data, a weld bead isosurface consisting of triangles is reconstructed with a marching cubes algorithm allowing us to generate more realistic weld seam shapes. We used multi-threaded programming for voxelization and isosurface extraction to reduce the computation cost on high-resolution virtual scenes. The isosurface extraction times for different thread counts and also a feature comparison with other simulators in the literature are shown in this paper.

The combination of at least two of the metal, ceramic or polymer groups at a macro level is called a composite material and, in this way, better properties are obtained. Composites can be partitioned into three groupings as layered, fiber and particle reinforced. Particulate composites offer flexibility in composition and component design and are isotropic. This investigation critically examines analysis techniques for particulate composites such as dimensional measurements, property distribution, composition and phase tests, density, and porosity tests (e.g. Archimedes, Pycnometer), hardness measurements (e.g. Brinell, Rockwell), mechanical properties through non-destructive and destructive testing (e.g. tensile, impact). In addition, application areas of particulate composites are highlighted, including Al-SiC composites for aircrafts, cemented carbides for tool metals, dental porcelain, electrical contacts, friction products, and thermal materials.

Anatomy is a branch of science that studies the normal shape and structure of the human body, the organs and the systems that make up the body, and the relationship between them. The skeleton, which forms the anatomical structure of the body and ensures its posture, consists of various bones and carries a large part of the body's load. Subjected to heavy body mass load, the knee joint is at great risk of strain and injury. Therefore, biomechanical analysis of artificial knee joint components is an important issue. While metals are used instead of bone in artificial knee joints used in knee prostheses, polymers act as a cartilage. Corrosion and wear are less in metal, and polyethylene-based artificial knee joints, and optimum articulation takes place between the joint surfaces. In this study, stainless steel, Co-Cr alloys, Ti alloys, and cementless implants used in knee joint implants are emphasized. Modeling of different structures of prostheses having 3D geometry using computer graphics programs such as finite element analysis, resonance imaging, or computed tomography was briefly evaluated. Finally, various biomechanical tests applied to knee implants were examined. Among these, especially tensile, compression, fatigue, three-point bending, torsion, indentation, biotribology tests, and kinematic and kinetic analyzes were examined. In conclusion, many advances have been made in experimental and analytical methods in the kinematics, kinetics, contact mechanics, and lubrication of artificial knee and hip joints in the recent years. These new techniques have allowed implant designers and clinicians to provide better, longer-lasting prostheses for thousands of people.

In this study, the impact resistance performance of the steel internal structure, which is fixed with screws between the front and rear plate, has a 90° bent form and is placed to deflect the penetrating bullet, was measured. This article presents the ballistic performance of the designed armor system against 7.62 mm armor-piercing projectiles with a velocity of 630 to 870 ± 10 m/s, coming at an angle of 90° to the front plate. The study was carried out both experimentally and numerically. Experimental results showed that remarkable ballistic results were obtained among the investigated materials examined in 32 mm thick aluminum-steel-aluminum sheet structures. Numerical and experimental results were compared and a significant correlation was found. In addition to the ballistic performance results, the samples were examined for fracture mechanisms by scanning electron microscopy and EDS analysis.

Purpose Paper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads. Design/methodology/approach AlSi12 alloys are used to manufacture the compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition. Findings AlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg 2 Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content. Originality/value In this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.

High-temperature materials play a significant role in sustainable engineering across various industries and applications. Sustainable engineering aims to design, develop, and implement solutions that minimize environmental impact, enhance resource efficiency, and promote long-term sustainability. The availability of substances that can be used efficiently at high temperatures allows pushing the limits of possible measurable demands. These substances include ceramics, polymers and metals. It is used in elevated temperature materials, aircraft and space structures, and space exploration. In this study, high temperature metals are classified including superalloys, platinum and refractory metals, refractory metals such as W, Nb, Mo, Ta. Also, ceramic materials are high temperature materials. Ceramics are criticized to use in elevated temperature due to their high hardness, extraordinary strength in compression, excellent thermal stability, short-term thermal extension and tremendously great melting temperature. Ceramics that encounter these standards are carbides and borides of Zr, Nb, Ta, Ti and Hf. In addition, steel, nickel and copper alloys used in aircraft engines, space shuttles and turbine blades from aerospace materials were investigated. In addition, powder metallurgy and sintering techniques, which are the most widely used production methods of high temperature materials, are emphasized. In this study, important characterization techniques for analyzing some sample surface and subsurface properties are reviewed. Again, in this study, the use of AES, XPS, SSIMS and LEED methods for the chemical examination of surfaces is discussed. Optical, electron, and scanning probe microscopy is used for pictorial inspection of inspection specimens and structures, obtaining data on surface, shape, colors, and numerous additional physical properties. Here, AFM, SEM, TEM, EDX, FIB and EMP methods are discussed. Among the material analysis devices, XRD, x-ray fluorescence spectrometry, low energy electron diffraction, neutron diffraction and electron microprobe devices were examined.

Various organs or tissues of living things can be damaged by diseases or biological, physical, and chemical damages. Their treatment has led to the development of numerous new biomaterials that enable the regeneration of many living things. Biomaterials constitute an important part of the materials consumed in the health sector today, and their market shares in the world are increasing day by day. When materials are reduced to nano-dimensions, their biological, physical, and chemical properties and functions change significantly and show improvements in the desired direction for many applications. Biomaterials have helped millions of people achieve a better quality of life in almost every corner of the world. Nanobiomaterials (NBMs) are used in many fields, and their most critical applications can be summarized as drug delivery, antibacterial applications, and bioimaging. Nanomaterials have significant toxicity values due to their high surface area and activity. In this chapter, a classification of NBMs has been made, and various properties have been reviewed. First, NBMs were divided into natural and synthetic. Two classes of natural biomaterials, protein-based and polysaccharide-based, were investigated. Synthetic biomaterials are divided into six groups as metallic, ceramic, polymeric, carbon-based, composite, and combined, and the general structures of the materials in this subgroup are reviewed. Then, the toxic, mechanical, electrical, magnetic, thermal, optical, and smart properties of NBMs were investigated. Also, drug delivery, antibacterial, bioimaging, tissue engineering, and infection properties of NBMs were discussed. Finally, after focusing on the functionalization of NBMs, the study's general findings are summarized in the conclusion section, and a perspective on the future of these materials is given.

Dental materials are used for restoration purposes for hundreds of millions of patients worldwide each year. In recent years, changes in the legislation of various countries and increasing social awareness have increased the expectation of products suitable for green production. In this study, the suitability of some dental filling materials for green production is discussed from various angles. Weighted aggregated sum product assessment (WASPAS) method was applied for a total of 14 sub-criteria in five main categories determined for green production. The results show that Ni-Fe-Cr alloy is the most suitable dental filling material for green production in many respects.

Laser coating is a material placement technique wherein a powder material is melted using a laser to coat a portion of a substrate. In this study, laser cladding and its applications are reviewed. First, background of the technique and its important parameters are highlighted. Then, control of laser cladding procedure is criticized. As an example of the process, laser cladding of titanium alloys is investigated. Finally, applications of laser cladding on gas turbine engines, dies and drilling spindles, tools, turbine blades are highlighted.

Surface hardening, a process involving a wide variety of techniques, is used to improve the wear resistance of parts without affecting the softer, harder interior of the part. This combination of hard surface and resistance to breakage on impact is beneficial in parts such as a cam or ring gear that must have a very hard surface to resist wear and a hard interior to resist the resulting impact. There are two distinctly different approaches to the various methods for surface hardening: a) Thermochemical diffusion methods that change the chemical composition of the surface with hardener species such as carbon, nitrogen and boron, b) Applied energy or thermal methods that do not change the chemical composition of the surface, but rather improve the properties by changing the surface metallurgy; that is, they produce a hard quenched surface without additional alloy types. In this study, materials selection for camshafts is reviewed and candidates from cast irons and steels are criticized and classical and computer based methods are employed for the best selection.