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In this investigation, the fabrication and mechanical properties of Bi metallic structure walls produced using wire-arc-additive manufacturing (WAAM) technique, employing stainless steel (SS) 316L and 304 filler wires, are examined. The findings reveal that SS 304 exhibits superior mechanical attributes compared to SS 316L, notably showcasing impressive tensile strength and exceptional ductility. Bi metallic structure, meticulously constructed using both SS 316L and SS 304 filler wires, effectively replicates these distinctive mechanical properties, rendering it highly desirable for application prioritizing mechanical performance. The observed enhancement in strength is attributed to variations in microstructure resulting from a complex thermal history. Microstructural and crystallographic analyses of Bi metallic structure are conducted using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron backscattered diffraction spectroscopy (EBSD), and X-ray diffraction spectroscopy (XRD). Additionally, tensile strength (TS) of Bi metallic structure surpasses that of WAAM SS 316L by 3.95%. This comprehensive research not only elucidates the intricate process of material selection in additive manufacturing but also underscores the significant potential of Bi metallic structure in meeting the stringent demands of engineering applications requiring exceptional mechanical properties.

Defect repair, one of primary concerns in the maintenance system for pipelines and other high strength components, is crucial in improving the reliability and economic benefits. Even though modern industries use several welding techniques to join metals, metal inert gas (MIG) welding is frequently preferred to weld stainless steel components by producing strong joints at high speed. In this study, MIG welding was used to butt weld 347 SS pipes. Research related to material failure is critical to engineers in order to find suitable application. Tensile test provides the static behavior of material. Therefore, predicting the strength and failure of material helps in satisfying industrial needs. Finite-element analysis (FEA) is an efficient technique to predict physical phenomenon virtually, therefore reducing the need for real-time prototypes. Johnson-Cook (J-C) material failure model is utilized to define failure in FEA model. Error percentage obtained while comparing FEA and experimental results of weld metal is 1.03%. Presence of niobium carbide is evident through the line map of energy-dispersive X-ray spectroscopy spectrum which prevents knife line attack through retarding chromium carbide precipitation at high temperature cycles. Welded samples with tensile strength of 583 ± 3 MPa exhibit better mechanical strength than base metal with tensile strength of 575 ± 2.5 MPa. This change in mechanical properties is caused by microstructural variation led by occurrence of constitutional supercooling while melt-pool solidifies. Failure mechanism of ductile fracture is understood from fractography (Tensile sample). Hence, this study provides a complete knowledge on failure mechanism of MIG-welded nuclear grade steel pipe under static loading. The failure mechanisms are explained in terms of FEA (J-C model) and fractography.

Additive manufacturing (AM) has been effectively employed in numerous applications due to its enhanced properties such as cost reduction, faster fabrication, and less material wastage. Fused filament fabrication (FFF) method is one of the most prevalent AM process broadly used for fabricating complex polymeric parts. Wood filler dispersed inside thermoplastic matrix (Polylactic Acid-PLA) is termed as Wood-PLA. Wood-PLA is widely employed in building constructions, fencing, and other structural applications. Whereas, Carbon-PLA is a thermoplastic polymer composed of carbon fiber and PLA. Due to its high strength, light weight, and durable properties, it is employed in various industries such as automotive, aerospace, and so on. Bi-materials are multi-functional materials, with unique characteristics at different regions of a part. Due to its unique properties, it is used in different integrated structural engineering applications such as defense, aerospace, energy, and safety gears. Bi-material could be fabricated using FFF through varying the filament after depositing few layers. Fabricated Bi-material exhibited mechanical properties such as tensile strength (16.7 ± 0.08 MPa), compressive strength (51.8 ± 3 MPa), flexural strength (72.1 ± 0.15 MPa), and impact energy (0.910 ± 0.02 J). Hardness value of Bi-material is 76.5 shore-D. The coupon studies revealed that Bi-material possesses better mechanical characteristics than Wood-PLA composites and is on par with Carbon-PLA. This work gives an insight into mechanical behavior of Bi-material (Wood-PLA/Carbon-PLA) under various loads. For microscopic examination (under optical microscopy), the sample was treated using acetone and sandpaper for better revelation of bonding of interface and buckling of layer. The brittle morphologies were observed in the fracture surface of failed sample using scanning electron microscope. The outcome of this study would open up opportunities that help in fabricating integrated structure used in engineering applications.

During fabrication of complex polymeric structure engineers need to compromise either accuracy or duration which hinders the production efficiency of the industries. Additive manufacturing is an evolving technology with great potential to achieve enhanced mechanical properties of materials over other manufacturing processes. Additive manufacturing effectively reduces lead time thus providing faster fabrication. A prevalent additive manufacturing method to fabricate polymeric structure is fused deposition modelling. Composite material generally possesses better mechanical properties than non-composite material. Polylactic acid is one of popular feedstocks used to fabricate components through fused deposition modelling. Functionally graded materials are structured to possess different mechanical properties towards a graded direction. Hence, this study aims to provide insight to the characteristics of the functionally graded materials structure fabricated with wood polymer composite and ceramic-reinforced polylactic acid. Mechanical tests such as tensile (smooth and V-notch), compression, flexural, impact, and hardness (Shore D hardness) are conducted for functionally graded materials structure and the extracted results are compared with the characteristics of wood polymer composite and ceramic-reinforced polylactic acid materials. The tensile strength of the functionally graded materials structure is found superior to weaker composites (wood polymer composite) and comparable to resilient materials (ceramic-reinforced polylactic acid). Microscopical examinations are carried out for the fabricated structure to ensure the quality. The fractured surfaces are examined using optical microscope to evaluate the mode of failures. The microscopic evaluation conducted for fabricated and fractured structure indicates robust bonding within and between (functionally graded materials interface) wood polymer composite and ceramic-reinforced polylactic acid structure.

The goal of this study is to provide first-hand knowledge to the industrial community on the mechanical properties of structurally graded materials (polylactic acid/ceramic-reinforced polylactic acid) wall fabricated through fused filament fabrication. Structurally graded materials are inhomogeneous materials that consist of two or more materials to produce a final structure with distinctive material properties. Because of their specific gradient, structurally graded materials are commonly used in various applications such as aerospace, medicine, optoelectronics, biotechnology, etc. These applications have certain requirements and significant properties such as thermo-mechanical resistance and chemical stability. Filaments of polylactic acid were deposited over ceramic-reinforced polylactic acid to fabricate structurally graded material walls. Coupon studies revealed that structurally graded materials exhibited mechanical properties (tensile strength: 19.1 ± 0.3 MPa, flexural strength: 100.1 ± 0.23 MPa, compressive strength: 64.6 ± 2.35 MPa, impact energy: 1.32 ± 0.038 J, and hardness: 81.5 Shore-D) that are better than polylactic acid. It is revealed that structurally graded materials possess better mechanical properties than polylactic acid and exhibit behavior similar to ceramic-reinforced polylactic acid. Fracture morphology indicates the occurrence of brittle fracture in tensile sample.

The aim of this study is to provide first-hand knowledge on additively manufactured structurally graded material (SGM) (polylactic acid / wood-fiber polymer composites) wall. Polylactic acid or polylactide is most effectively used in manufacturing plastic films, bottles, biodegradable medical devices, textile, and agricultural goods. Wood-fiber polymer composites are essentially used in furniture, particleboard, oriented strand board, medium-density fibreboard, plywood, and constructions. SGM is characterized through the change in material composition that is applicable to specific functions. Fabricated SGM exhibited mechanical property such as tensile strength (15.78 ± 0.05 MPa), compressive strength (46.8 ± 2.7 MPa), flexural strength (88.2 ± 0.15 MPa), and impact energy (1.64 ± 0.07 J). Hardness value of SGM is 74.5 shore-D. The coupon studies revealed that SGM possesses better mechanical characteristics than wood-fiber polymer composites and is on par with polylactic acid. The observed morphologies on fracture surface indicate the brittle nature of fracture. This SGM come under advanced materials that are utilized in biomedical, defence, energy, aviation, and nuclear sector, for integrated structural and thermal application.

This study investigates the application of wire arc additive manufacturing (WAAM) for fabricating functionally graded materials (FGMs), focusing on FGM walls (SS 347/316L) using gas metal arc welding. FGMs offer advantages for parts requiring dissimilar welding, providing seamless material transitions without compromising properties. Targeting critical sectors like marine, aerospace, and pressure vessels, the fabricated FGM wall demonstrates superior characteristics, including enhanced tensile strength and microstructural properties compared to traditional wrought alloys. The FGM exhibits a strength of 3.47% greater than that of the stronger material (SS 347), with a simulated strength of 539.9 MPa. The outcomes of the tensile test show a simulated error percentage of less than 1% (0.534%). The study also highlights the potential of WAAM in producing high-performance materials for demanding applications such as aircraft engines, nuclear reactors, and oil and gas pipelines, emphasizing its significance in industrial settings.

This investigation aims to provide functional insight into simulating the tensile behavior of additively fabricated stainless steel 316L plate using finite element simulation and the Johnson-Cook model of ductile damage. The stainless steel 316L plate is fabricated through wire arc additive manufacturing using ideal process variables selected through numerous trial and error experiments. There is a significant increase in the strength of additively fabricated specimens (517.9 MPa) than wrought alloy samples (491.3 MPa). Finite element simulation was used successfully to simulate the tensile test, and the outcomes were predicted with an error percentage of less than 1. The significant enhancement in the strength is due to variations in the microstructure such as dendritic growth, phase changes influenced by complex thermal cycle, and residual δ-ferrite in wire arc additive manufacturing plate. The presence of residual δ-ferrite is also clear through the evaluation of ferrite number as it varied from bottom to top in the range of 5.2–4.9.

Additive manufacturing (AM) is an extending manufacturing method which has many advantages such as minimalistic material wastage, less fabrication time and so on, over other manufacturing technologies such as subtractive, moulding, casting, etc. Strength enhancement of additively fabricated structures is an active area of study and much research was evolved in terms of developing innovative feedstock for AM. Polymers and their composites gain great attention in the research community. Even though many composites available commercially were observed with enhanced properties, most of them are not sustainable and recyclable in nature. Eggshell is a naturally available calcium carbonate, which gets wasted in a huge amount. Such eggshells were synthesized and transformed into nanosized for inclusion of filler in polylactic acid (PLA) matrix. PLA is a bio-degradable polymer with numerous applications and is one of the popular feedstocks for fused deposition modelling. This study explains the proper procedure to extrude commercial-grade eggshell-based composite filaments and qualities of such composites would be elaborately discussed with the help of single fibre tensile test, scanning electron microscopy and X-ray diffraction. Totally five filaments such as PLA, 5, 10, 15 and 20 wt % of eggshell in composites were extruded by following proper sonication and suitable filament extrusion process. 15 wt % composite seems to be the best among all filaments and possesses better characteristics than all other filaments.