Materials Science Forum Vol. 1151

Abstract: In the field of ballistic protection systems, Wire Arc Additive Manufacturing (WAAM) technology represents an innovative approach. WAAM offers a novel solution for producing complex components in ballistic protection systems. The process involves using an electric arc to melt metal wire, which is deposited layer by layer to form the desired structure. This method enables the creation of intricate geometries, presenting new possibilities for enhancing the ballistic resistance of protective systems. In this study, WAAM technology was employed to manufacture strike face layers for ballistic protection, with two types of welding wires selected to fabricate bimetallic composites. The produced components were evaluated in three configurations (COW, MCH, and Bim), which were subjected to ballistic testing with 7.62 mm FMJ M80 projectiles in accordance with the NATO AEP-55 STANAG 4569 standard. The results revealed that configuration II (MCH) exhibited complete ballistic resistance, meeting NATO AEP-55 STANAG 4569 level 1, while configuration III (Bim) demonstrated a higher velocity reduction compared to configuration I (COW).

Abstract: Tools applied in various cutting processes are constantly exposed not only to thermal, mechanical but also chemical stresses, which has a significant impact on the wear of the cutting tool, but also on the cutting performance itself. By measuring the components of the cutting force, we can predict the wear or suitability of the cutting tool for machining given types of materials. The present study investigates the effect of changing the shape of the tool geometry on the magnitude of cutting forces in turning tool steels. The measurement of cutting forces was carried out on a conventional lathe with a Dynamometer attachment, interchangeable cutting inserts of DNMG and WNMG type were used as tools, tool steels produced by PM and conventional metallurgy were used as the machined material. The cutting tools were selected regarding their common use in engineering production, the tool steels were selected with regard to their application in industry in the production of rotary tools.

Abstract: This study focuses on the simulation and experimental validation of orbital laser welding for aluminum alloy tubes. The trials were conducted on the TRU LASER ROBOT 5020 system by TRUMPF, which features a 30 kg robotic arm, a diode-pumped disk laser with a beam quality of 8 mm*mrad, and a minimum output power of 4000W on the workpiece. Aluminium 6082 Tubes were mounted on a fixture attached to an integrated rotary table, and a series of tests were performed with varying levels of edge preparation accuracy and different laser beam parameters such as power and head linear speed. The simulation was carried out using Ansys Mechanical witch ACT toolkit heat source model. The thermocouple mesurments and metallographic tests was a key parameter used to validate the simulation results. The temperature distribution during welding was compared with simulation results to adjust the thermal properties of the material within the simulation model. The combined simulation and experimental analysis provide a framework for optimizing the laser welding process, enabling the reduction of costly experimental trials by simulating different parameter ranges.

Abstract: In this paper, the steels used in MN knife mills, which are used for plastic recycling, are investigated. 90MnCrV8 steel is commonly used in these mills, which will be replaced by X153CrMoV12 steel. The main goal of the presented contribution is to perform tribological tests and verify the wear rate of both steels experimentally with subsequent practical verification in the knife mill MN. Partial results relate to the analysis of hardness, roughness, and overall wear mechanism. A hardened steel ball of material G40 with a diameter of 4.76 mm was used as the contact material. The steel ball performed reciprocal linear motion on the surface of the experimental materials at room temperature and without the use of lubrication. The measurements were carried out in three-time intervals of 20, 30 and 40 min. The experimental material X153CrMoV12 can fully replace the material 90MnCrV8 in processes where its degradation occurs due to the friction mechanism. The material X153CrMoV12 showed significantly better results in all the values ​​we measured. It can be expected that the knife in the MN knife mill made of X153CrMoV12 steel will last several times longer in the working environment, which was also proven by practical verification in production.

Abstract: The promotion of green and low-carbon initiatives has spurred the application of lightweight materials in steel/Al car bodies. The development and utilization of large Al alloy die-casting (DCAA) materials and thermo-formed steel plates (TFSS) impose higher demands on joining technologies of the steel/Al dissimilar material. Taking the innovative body with DCAA and TFSP as a case, this paper systematically investigates the principles, characteristics and forming progress of force-self-piercing riveting(FSPR) joining technology for two-layer and three-layer plates with DCAA and TFSP. The types of test samples, the combination of plates and the test methods of mechanical properties are designed. Using the TL4225/C611/CR5 plate combination, the riveting and forming processing, the microstructures and morphologies were studied. Based on it, the methods to achieve high-quality joints were obtained. For the joining of two-layer plates containing DACC and TFSP, better joint forming and higher joint strength can be obtained for the ideal arc gap filling. For the joining of three-layer plates, TFSP will affect the filling effect for the elastic-plastic deformation of the middle layer during the forming. Although the joint can meet the product design, but the strength index is significantly lower than that of the two-layer plates. Based on the relevant data in the course of this experiment, general rules of product design for FSPR joining, such as joining space, flange edge size, plate strength and plate thickness, were analyzed and summarized combining plate characteristics, plate combination, die structure, joining method, joint strength and weld accessibility. The study will provide the technical support for the application of DCAA parts and TFSP in car bodies.

Abstract: This study presents a novel work on the synthesis of Mn-doped ZnO microstructures via thermal oxidation of Zn metal sheet in the presence of MnCl₂ mist. Structural analysis via XRD shows the growth of ZnO particles for the sample oxidized in water vapor while simonkolleite and ZnO both formed for the samples oxidized with MnCl₂. Shifting of ZnO diffraction peaks suggests incorporation of impurity atom within the crystal lattice of the material. SEM images show layered formation of simonkolleite at the bottom and ZnO particles at the top of the substrate. At increasing MnCl₂ concentration, the growth of ZnO particles and simonkolleite phases were hampered which is attributed to the hindering of the oxidation process by the presence of Cl^- anion.

Abstract: This study investigated the correlation between the oxygen-argon ratio and crystal phase, the surface flatness and electrical properties of ZrO₂ thin films The films were deposited on transparent conductive indium tin oxide (ITO) substrates by DC magnetron sputtering. ZrO₂ films exhibit ZrO cubic and ZrO₂ monoclinic mixed phases when deposited with a low oxygen-argon ratio of 5:45. As the oxygen-argon ratio increases, a gradual phase transition ZrO to orthorhombic ZrO₂ occurs. Besides, the ZrO₂ film deposited with an oxygen-argon ratio of 10:40 exhibits highest resistance to electric field strength, and lowest leakage current.

Abstract: It is shown experimentally and numerically that quenching (Melt Quenching - MQ) of REM-containing (up to 40 wt.%) Fe-B-Nd melt by inert gas flow (Gas Atomisation Method - GAP) in NH3-containing atmosphere makes it possible to obtain spherical particles with a given fractional and chemical composition and characterised by increased corrosion resistance. The applicability of the obtained particles in the traditional powder technology for the formation of anisotropic and isotropic sintered magnets is established. It is shown that MQ GAP can regulate the functional properties of sintered magnets by mixing different chemical and fractional compositions. It is shown that heat treatment of MQ GAP powders improves their magnetic hysteresis properties and magnetoplasts made from them. The applicability of the obtained MQ GAP REM-containing particles for cladding technologies and additive processes is proved. Hybrid laser & micro-casting surfacing technology for additive processes of processing Fe-Nd-B ternary and MQ GAP alloys into micromagnets - 'Hybrid laser & micro-casting technology for surfacing in additive processes' is proposed. The possibility of realising the described technology for other MQ GAP REM containing alloys with multicomponent low melting eutectic in the intergranular space capable of amorphising at cooling rates of 10³÷10⁵ K/s has been shown.

Abstract: The absence of materials with excellent thermal conductivity inside the heat not burning tobacco affects the smoking taste, so the exploration of high thermal conductivity materials has attracted much attention. Graphene oxide (GO) is widely used as a functional material due to its high thermal conductivity, but there are some risks associated with its application in food. Through the esterification reaction between cellulose (soluble and edible) and GO, the covalent bond fixation of graphene thermal conductive material was realized, and the functional cellulose material with high thermal conductivity was formed in the study. The coupling form, mechanical property stability, microstructure and thermal conductivity were characterized by FTIR, DSC and SEM, and the results showed that the carbonyl peak of graphene in the thermal conductive adhesive was transferred from 1651 cm^-1 to 1716 cm^-1, indicating that graphene was successfully attached to cellulose through ester bond. Furthermore, the decomposition temperature of the thermal conductive adhesive is about 300 °C, which meets the requirements for stability, and the addition of the thermal conductive adhesive does not change the apparent structure of cut tobacco. The thermal conductivity coefficient of the reinforced thermal conductive tobacco obtained in this study is between 0.5-1.4 Wm^-1K^-1 (without thermal conductive adhesive: 0.135 Wm^-1K^-1), which meets the actual thermal conductivity requirements. The thermal conductive adhesive material has good adhesion with tobacco flakes, and is easy to dry, which also simultaneously can block the migration risk of graphene material to human body during tobacco smoking. This work provides a certain reference for the development of graphene reinforced thermal conductive adhesive in the field of new tobacco.