Friction Stir Extrusion (FSE), Direct Extrusion (DE) and Indirect Extrusion (IE) are all valid processes for the production of round profiles. However, differences and similarities between them have yet to be analyzed by the scientific community, since with the same geometry, each technology instills specific properties to the extruded product. In this context, the present work proposes an in-depth analysis via QForm UK Finite Element Method (FEM) software of the effect that each process has on a AA6061 extruded wire. Various combinations of rotational speed (200, 400, 600 rpm), feed rate (1, 2, 3, 4 mm/s) and pre-heating temperature (450, 500°C) were analyzed to assess differences and similarities between FSE, DE and IE. The feedstock material for FSE was chosen to be powder, while a solid billet was used for conventional extrusion.

Wire Arc Additive Manufacturing (WAAM) is a promising technology for producing large, high-performance metallic components, though process stability and geometric control remain critical challenges. The present work investigates the influence of deposition trajectory on the geometry, surface quality, and microhardness of wire arc additive manufactured Inconel 625 walls, produced by a Cold Metal Transfer (CMT) process. A conventional linear double-pass strategy is directly compared with a single-pass triangular weave trajectory under equivalent heat input per unit length, in order to isolate the effect of the torch path from other process variables. Single-layer and multi-layer walls were fabricated and characterized in terms of geometry, dimensional stability, surface waviness, and Vickers microhardness. The results show that the weave trajectory leads to improved geometric consistency, reduced variability, and significantly lower surface waviness compared to the linear strategy, while maintaining comparable mean wall width and microhardness. These findings demonstrate that appropriate trajectory design can enhance geometric stability and near-net-shape capability in WAAM-CMT without altering thermal input or material properties.

Additive manufacturing gains ground on the production of high-precision metallic components with varying thickness. As the material thickness alters in the various locations of the product, it is eminent that the material mechanical properties might vary. In the present contribution, a preliminary study was performed to investigate the resistance to fracture of additively manufactured AlSi10Mg material with varying thicknesses. To this end, fracture toughness specimens of compact tension geometry with varying thicknesses from 3 to 15 mm were additively manufactured, machined and tested. The results showed that with increasing the specimen thickness, critical stress intensity factor K cr decreases gradually from 38 MPa√m up till 31 MPa√m for the lower and higher investigated thicknesses, respectively. Finally, it was noticed that even the 15 mm thickness (higher investigated) does not satisfy the plane strain fracture mechanism and therefore all investigated specimens were in plane-stress condition.

The mechanical properties and electrical conductivity of the Al–0.15Fe–0.5Si–0.5Mg–0.2Mn alloy with a Mg/Si ratio of 1 were investigated using optical microscopy, scanning and transmission electron microscopy, tensile testing, Vickers hardness measurements, and specific electrical resistivity measurements. To analyze the electrical conductivity data, the unit % IACS was used, calculated as a percentage relative to the conductivity of annealed copper. The alloy was studied in the as-cast condition, in the deformed condition (following extrusion and drawing), and after heat treatments: HT1 — solution treatment at 530°C and aging at 140°C for 8 hours, and HT2 - solution treatment at 560°C and aging at 175°C for 6 hours. The microstructure of the investigated alloy varied depending on the condition and heat treatment parameters, consisting of an aluminum matrix and strengthening particles with different morphologies and chemical compositions. For rods in the as-cast state, the conductivity was 55% IACS, ultimate tensile strength (UTS) — 150 MPa, and elongation — 14%. After HT1: 51% IACS, UTS — 140 MPa, elongation — 19%. After HT2: 51% IACS, UTS — 195 MPa, elongation — 19%.

This study presents the results of both non-destructive (radiography and computed tomography) and destructive (light optical and scanning electron microscopy) evaluations of operational degradation in welded joints of ESW (electroslag welding) pipelines. Microbiologically influenced corrosion (MIC), potentially induced by manganese-oxidizing microorganisms (MOMOs), was investigated as a plausible degradation mechanism. Extensive subsurface corrosion cavities were identified beneath the internal surface of the pipelines. The presence of MnO 2 globules near these cavities supports the hypothesis of MOMO-induced corrosion.

This investigation reports the successful synthesis and characterization of a co-crystal composed of paracetamol (PCM) and metal sulfates of zinc and iron using an adapted antisolvent addition technique which leveraged the antagonistic solvent affinities of PCM and the metal sulfates. Ethanol and water acted as solvents for PCM and the metal sulfates, respectively, while simultaneously serving as antisolvents for the other constituent. Scanning Electron Microscopy (SEM) micrographs revealed crystals exhibiting a rod-like structure and a surface covered by flakes, which are both characteristic features of PCM and zinc sulfate, suggesting the formation of a new crystalline phase. This is further supported by the distinct powder x-ray diffraction pattern for the co-crystal when compared with that of the individual constituents. Analysis of Fourier Transform Infrared (FTIR) spectra suggests that the interacting functional groups which formed a new hydrogen bond network are the amide N-H and the water in the aquo complex formed by the metals in aqueous solutions. The findings highlight the simplicity of the crystallization technique and provide insights into the structural and mechanistic aspects of organic-inorganic co-crystals. This study contributes to the advancement of co-crystal engineering and lays the groundwork for exploring the pharmaceutical and functional applications of PCM-metal sulfate co-crystals.

Austenitic stainless steels are characterised by excellent corrosion resistance and good formability, but their low hardness and fatigue life are limitations in demanding applications. The aim of this study was to analyze the effect of solution annealing and plasma nitriding on the microstructure, hardness and fatigue properties of AISI 304 steel. The experimental material was examined in three states: initial, after solution annealing and after plasma nitriding. Solution annealing resulted in the removal of deformation martensite, giving a homogeneous austenitic structure with a decrease in hardness. On the contrary, plasma nitriding produced a hard nitride layer (1291 HV0.01), while no martensite retransformation took place. The results of the fatigue tests showed that the specimens after plasma nitriding reached the highest fatigue limit (878 MPa), while the specimens in the initial condition had the highest number of cycles to fracture. Fractographic analysis revealed typical fatigue failure characteristics in all conditions. The study highlights the possibility of optimising the fatigue properties of austenitic steels through an appropriate combination of thermal and chemical-heat treatments.

Welding distortion remains a significant challenge in vehicle structures incorporating aluminum components. This study investigates the application of pre-tension to mitigate welding distortion in an aluminum T-joint structure. Through finite element (FE) simulation, the mechanism by which pre-tension alters the residual stress state and reduces distortion is analyzed and comprehensively explained. Based on the findings, an optimized pre-tension condition is proposed to minimize welding distortion in the T-joint configuration.