The Effect of Reinforcement Preheating Temperatures on Tribological Behavior of Advanced Quranic Metal-Matrix Composites (QMMC)

The growing applications of iron/copper bimetallic composites in various industries are increasing. The relationship between the properties of these materials and manufacturing parameters should be well understood. This paper represents an experimental study to evaluate the effect of reinforcement (steel rod) preheating temperature on the mechanical properties (bond strength, microhardness, and wear resistance) of copper matrix composites (QMMC). In preparing the QMMC samples, the melted copper was poured on a steel rod that had been preheated to various temperatures, namely, room temperature, 600 °C, 800 °C, and 1200 °C. Properties of the QMMC (interface microstructure, interfacial bonding strength, microhardness, and wear) were investigated. The experimental results revealed that the best bond between the copper matrix and steel rod formed only in the composites prepared by preheating the steel rods with temperatures lower than the recrystallization temperature of steel (723 °C). This is because the oxide layer and shrinkage voids (due to the difference in shrinkage between the two metals) at the interface hinder atom diffusion and bond formation at higher temperatures. The microhardness test showed that preheating steel rod to 600 °C gives the highest value among all the samples. Furthermore, the QMMC’s wear behavior confirmed that the optimization of preheating temperature is 600 °C.

ADDITIVE MANUFACTURING PARAMETERS OPTIMIZATION OF Ti6AL4V ELI FOR MEDICAL IMPLANTS

Additive manufacturing (AM) of titanium (Ti) alloys has always fascinated researchers owing to its high strength to weight ratio, biocompatibility, and anticorrosive properties, making Ti alloy an ideal candidate for medical applications. The aim of this paper is to optimize the AM parameters, such as Laser Power (LP), Laser Scan Speed (LSS), and Hatch Space (HS), using Analysis of Variance (ANOVA) and Grey Relational analysis (GRA) for mechanical and surface characteristics like hardness, surface roughness, and contact angle, of Ti6Al4V ELI considering medical implant applications. The input parameters are optimized to have optimum hardness, surface roughness and hydrophilicity required for medical implants.

ВПЛИВ ПАРАМЕТРІВ АДИТИВНОГО ВИРОБНИЦТВА НА ВЛАСТИВОСТІ ВИРОБІВ З ФОТОПОЛІМЕРУ

Purpose. Study of the influence of additive manufacturing parameters and post forming operations on complex mechanical properties of the articles formed from UV curable acrylic oligomer. Methodology. Determination of physical and mechanical properties of standard samples which was formed by additive manufacturing technics from UV curable polymer. Tensile strength and relative elongation at brake according to ISO 527-2:2012, impact strength according to: ISO 179-1:2010. Durometer hardness according to:ISO 2039-1:2001. Bending modulus according to: ISO 178:2010. Density according to: ISO 1183-1:2019Findings. Additive manufacturing parameters for stereolithography process was studied for liquid UV curable acrylic oligomer. Study was focused on influence of forming settings and post forming treatment of complex mechanical properties of final articles which was shaped as standard testing samples. Properties of additive manufactured samples was compared with the properties of samples which was cured by UV light is bulk inside shaped cavity with the same geometrical dimensions. Correct post forming treatment results in up to 2 – 3 times increase in tensile strength. Post forming treatment is necessary for achieving functional level of mechanical properties, comparable to the properties of typical industrial polymers. Study of influence of UV light exposure during additive manufacturing shows double fold increase in tensile strength but reduce overall forming speed. Impact strength increase with increasing exposure time and significantly increase with duration of post forming treatment. Post treatment operations with correct parameters can result in forming articles with level of properties sufficient for functional applications. Originality. Study was focused on mechanical properties of UV curable polymer in dependence from forming parameters of additive manufacturing process and post treatment operations. Application of correct post forming setting can lead to material properties with valuable for functional applications.Practical value Optimal parameters for additive manufacturing process based on UV curable resin and LCD exposure technology was investigated. Forming and post forming parameters significantly influence complex mechanical properties of formed articles.

Design of Customized TPU Lattice Structures for Additive Manufacturing: Influence on the Functional Properties in Elastic Products

This work focuses on evaluating and establishing the relationship of the influence of geometrical and manufacturing parameters in stiffness of additively manufactured TPU lattice structures. The contribution of this work resides in the creation of a methodology that focuses on characterizing the behavior of elastic lattice structures. Likewise, resides in the possibility of using the statistical treatment of results as a guide to find favorable possibilities within the range of parameters studied and to predict the behavior of the structures. In order to characterize their behavior, different types of specimens were designed and tested by finite element simulation of a compression process using Computer Aided Engineering (CAE) tools. The tests showed that the stiffness depends on the topology of the cells of the lattice structure. For structures with different cell topologies, it has been possible to obtain an increase in the reaction force against compression from 24.7 N to 397 N for the same manufacturing conditions. It was shown that other parameters with a defined influence on the stiffness of the structure were the temperature and the unit size of the cells, all due to the development of fusion mechanisms and the variation in the volume of material used, respectively.

An Introduction on the Laser Cladding Coatings on Magnesium Alloys

Magnesium alloys are a promising structural material to be used as a substitute for metals traditionally used in the automotive and aircraft sector. However, magnesium alloys have poor mechanical properties and corrosion resistance. These handicaps can be overcome through the application of coatings with improved properties. Laser cladding is a potential coating fabrication process. Furthermore, the low vaporization temperature of magnesium and the coating-substrate dilution problems increase the difficulty to coat magnesium substrates. The aim of this research is to analyze the state of art in magnesium laser cladding and investigate the effect of the most important fabrication parameters on the interaction of the different coating-substrate systems used on the mechanical properties and corrosion resistance. In addition, this work provides a guidance on laser cladding best practices for these alloys. Knowledge of how the different coating manufacturing parameters affect the final surface properties of magnesium alloys is essential for the implantation of these materials in applications for which they are currently limited.