Mechanical Properties Of Parts Research Articles

Correlating polyamide powder flowability to mechanical properties of parts fabricated by additive manufacturing

This study investigates the relationships between the flow properties of five blends of polyamide 12, with the mechanical and physical characteristics of the fabricated components. The bulk properties and flowability of the powder blends were characterised using powder rheology. Absolute, or skeletal volume of 3D printed cubes were measured using helium pycnometry. The tensile behaviour and surface hardness of specimens fabricated from the five blends were determined. The mechanical properties of the samples were correlated with the flow behaviour of the powder used. Comparison of the powder flow measures with the mechanical properties of the fabricated parts allows for prediction of final product quality prior to printing. Understanding the relationships between these parameters helps to identify and develop powders that enhance both process efficiency and the mechanical properties of the final product.

Порівняльні дослідження механічних властивостей зразків сталі 316L, виготовлених на машині ALFA-150 на відповідність світовим аналогам

The purpose of the work is to study the microstructure and mechanical properties of 316L stainless steel samples made by the SLM method. 316L stainless steel has been extensively studied for the state after fabrication by selective laser melting (SLM). This is due to the wide use of this material in various industries, as it demonstrates sufficient corrosion resistance and excellent plasticity. Thus, its application can be found in the biomedical, aerospace, automotive and marine fields. Some of the studies conducted have shown the ability of SLM to improve the mechanical properties of parts compared to traditional methods. Metallographic analysis, determination of mechanical properties, and chemical analysis were used. The object of the study was austenitic grade 316L stainless steel. The material for making the samples was a 316L alloy powder with a particle size of 45 + 15 μm. Experimental samples for tensile tests were built on the equipment of "Additive Laser Technologies of Ukraine" LLC (Alfa-150) using SLM technology in identical modes: laser power - 290 W, scanning speed - 1100 mm/s, distance between tracks – 0.11 mm, scanning strategy - checkerboard fields, scanning order - Zig-Zag, field size - 5 mm, rotation of the layer relative to the previous one - 67°. From the results of the analysis of mechanical properties, it was established that the samples made on the 3-D printer of Additive Laser Technologies of Ukraine LLC are not inferior in terms of quality to leading global companies, and in some characteristics even exceed them. It should be noted that the results of determining the characteristics of the experimental samples were compared with the properties of the samples manufactured according to the optimal process parameters on the equipment of different manufacturers, but do not include the influence of the thickness of the applied layer. Comprehensive studies of the mechanical properties of the samples made of 316L steel showed full compliance with the samples produced on the equipment presented on the world market for the production of special-purpose products.

Experimental and numerical study of the influence of FFF process parameters on the flexural properties of 3D printed medical devices and personal protective equipment

3D printers are increasingly used after the spread of the COVID-19 pandemic. This machine was used to overcome the lack of medical devices and personal protective equipment. In order for printed objects to be useful in the medical field, the mechanical properties of these objects must be known. The main objective of this study is to assess the mechanical properties of parts manufactured in polylactic acid by a 3D printer machine. The mechanical properties are determined from the experimental results of the three-point bending test. The results obtained show that the mechanical properties depend on the process parameters. The analysis of variance was used to determine the printing parameters that have a statistically significant effect on the mechanical properties. The optimal printing parameters are determined to manufacture parts with high mechanical performance and used them in complete safety. The finite element analysis was performed using ANSYS mechanical APDL software to validate the experimental results.

Investigation of Mechanical Properties of Parts Fabricated with Gas- and Water-Atomized 304L Stainless Steel Powder in the Laser Powder Bed Fusion Process

The use of gas-atomized powder as the feedstock material for the laser powder bed fusion (LPBF) process is common in the additive manufacturing (AM) community. Although gas-atomization produces powder with high sphericity, its relatively expensive production cost is a downside for application in AM processes. Water atomization of powder may overcome this limitation due to its low cost relative to the gas-atomization process. In this work, gas- and water-atomized 304L stainless steel powders were morphologically characterized through scanning electron microscopy (SEM). The water-atomized powder had a wider particle size distribution and exhibited less sphericity. Measuring powder flowability using the Revolution Powder Analyzer (RPA) indicated that the water-atomized powder had less flowability than the gas-atomized powder. Through examining the mechanical properties of LPBF fabricated parts using tensile tests, the gas-atomized powder had significantly higher yield tensile strength and elongation than the water-atomized powder; however, their ultimate tensile strengths were not significantly different.

Prospects for the Implementation of New Materials and Technologies in the Aerospace Industry

Abstract This article considers the main materials used to make aircraft, both fuselage and engines. First, the problems that force developers to introduce new materials in aircraft production are identified. We then present features of the introduction of heat-resistant titanium alloys, ways of improving the mechanical properties of parts made of titanium alloys, and methods of manufacturing complex details. Other promising materials for the aviation industry, such as high-entropy alloys, quasicrystals, carbon-carbon materials, and nickel foam, are also considered.

Experimental Investigation on Mechanical Properties of Part Fabricated by Wire Arc Additive Manufacturing Process

Additive manufacturing process is a method of layer by layer joining of materials to create components from three-dimensional (3D) model data. After their introduction in the automotive sector a decade ago, it has seen a significant rise in research and growth. The Additive manufacturing is classified into different types based upon the energy source use in the fabrication process. In our project, we used self-build CNC machine that runs MACH3 software, as well as the MACH3 controller is used to control the welding torch motion for material addition through three axis movement (X, Y and Z). In the project we used ER70 S-6 weld wire for the fabrication and examined its microstructure and mechanical properties. Different layers of the specimen had different microstructures, according to microstructural studies of the product. Rockwell hardness tester used for testing hardness of the product. According to the observation of the part fabricated components using the Wire Arc Additive Manufacturing process outperformed the mechanical properties of mild steel casting process. The product fabricated by Wire Arc Additive Manufacturing process properties is superior to conventional casting process.

Flow behavior and microstructure evolution of Ti-6Al-4V titanium alloy produced by selective laser melting compared to wrought

Nowadays, selective laser melting (SLM) represents an option for manufacturing parts from titanium alloys, especially from Ti-6Al-4V alloy. However, mechanical properties of parts made of SLM-produced Ti-6Al-4V, such as ductility and fatigue resistance, are significantly lower than that of wrought ones. The promising way to improve mechanical properties of SLM parts without expensive hot isostatic pressing can be combination SLM and deformation post-processing. Therefore, the goal of the present study is to investigate the flow stress behavior and microstructure evolution of Ti-6Al-4V fabricated by SLM in a wide temperature range in comparison with conventional manufactured material. In contrast to wrought material, SLM-produced Ti-6Al-4V shows high plastic flow instability at test temperatures of 20–900 °С, which was demonstrated via temperature sensitivity and softening rate. FEM-simulation of hot isothermal compression of samples was conducted in order to compare the deformation inhomogeneity between SLM-produced and wrought materials, namely, local strains e in the severe plastic deformation and dead metal zones. The microstructure in these characteristic zones of both materials deformed in (α + β)-field was examined by means of optical microscopy. The type of microstructure and grain size of the SLM-produced and wrought material were studied. It turned out that the deformation of SLM-produced Ti-6Al-4V at a lower temperature (800 °C) and a higher strain rate (1 s−1) makes it possible to obtain ultrafine-grained microstructure. This, in turn, opens the door to the production of Ti-6Al-4V parts with high mechanical properties via processing route SLM + metal forming.

A Survey of Mechanical Property Variability of Additively Manufactured Metals

Abstract Metal additive manufacturing (AM) processes, such as laser powder bed fusion, allow for the realization of parts with features and characteristics that cannot be achieved with traditional material removal manufacturing technologies. Despite impressive applications of metal AM parts in demanding aerospace applications, there remain concerns about the variability in mechanical properties of parts made with these processes. This variability leads to concerns by program managers and other decision-makers and a reluctance to potentially use metal AM parts in applications where they would otherwise be beneficial. Some of this reluctance might be assuaged if the actual property variability was better known. Here, we examine the literature of metal AM tensile property data to quantify variability in the metal AM process and compare it to the variability found in traditionally fabricated metals. It is shown that the variability in tensile material properties is somewhat similar between AM metals and conventional metals.

ABS filament moisture compensation possibilities in the FDM process

The article presents the possibility of compensating for the negative impact of filament humidity on the mechanical properties of parts produced by the FDM method by selecting appropriate process parameters, such as: layer thickness, deposition speed, deposition temperature and chamber temperature. The rules for selecting the process parameters were established on the basis of the results of the experiment, which allowed to identify the main and internal relations between the properties of the product and the process parameters, as well as the humidity of the filament. It was found, that layer thickness is the parameter of the FDM process which compensates for the negative impact of material moisture to the greatest extent.

Numerical and Experiment Studies of Different Path Planning Methods on Mechanical Properties of Composite Components.

The purpose of this paper is to study the effects of different trajectory planning methods on the mechanical properties of components. The scope of the research includes finite element simulation calculation and experimental tests of the actual structure. The test shall be carried out in the whole load range until the failure of the structure occurs. Taking the composite conical shell as an example, a variable angle initial path generation method of the conical shell surface is proposed, and the parallel offset algorithms based on partition and the circumferential averaging are proposed to fill the surface. Then, finite element analysis is carried out for the paths that satisfy the manufacturability requirements, the analysis results show that the maximum deformation and maximum transverse as well as longitudinal stress of fiber of circumferential averaging variable angle path conical shell are reduced by 16.3%, 5.85%, and 19.76%, respectively, of that of the partition variable angle path. Finally, the strength analysis of conical shells manufactured by different trajectory design schemes is carried out through finite element analysis and actual failure tests. The finite element analysis results are in good agreement with the experimental results of the actual structure. The results show that the circumferential uniform variable angle has good quality, and it is proved that the path planning algorithm that coordinates path planning and defect suppression plays an important role in optimizing placement trajectory and improving mechanical properties of parts.

Modeling the influence of fused filament fabrication processing parameters on the mechanical properties of ABS parts

Modeling the influence of the processing parameters of fused filament fabrication (FFF) on the mechanical properties of FFF fabricated parts is a challenging task due to the complex dynamics and the large number of factors that affect the quality of the fabricated parts. Therefore, optimizing the mechanical properties of parts fabricated using FFF usually requires a considerable number of test samples. Most past studies have focused on the main effects of the processing parameters and have ignored the interactions between the parameters or their non-linear effects on the mechanical properties of FFF fabricated parts. In the work presented, the effects of the layer thickness, nozzle temperature, infill percentage, and infill pattern are investigated to achieve the fabricated parts' optimum strength and stiffness. A group of Artificial Neural Networks (ANN) was used to model the influence of these processing parameters on the mechanical properties of FFF fabricated ABS parts. The Design of Experiments (DOE) approach was utilized to minimize the number of tests needed to study the investigated parameters. Response Surface Methodology (RSM) and Taguchi's orthogonal arrays were used to generate the training and testing data sets used to develop a group of ANN models and evaluate their performance. Furthermore, the fitness of ANN models was compared to the regression models of the RSM and Taguchi's DOE. It was found that some parameters exhibit strong interaction and nonlinear effects on the strength, stiffness, and ductility of FFF fabricated parts. The coefficient of determination R2 indicates that the ANN models were more accurate at predicting the mechanical properties than DOE regression models. The contour plots show that generally, increasing the layer thickness and infill percentage increase the tensile strength and the elastic modulus and that increasing the nozzle temperature is important when thick layers are used. For the ductility, the infill pattern is the most significant parameter, with linear infill yielding the highest ductility and triangular yielding the lowest. Lower nozzle temperature generally improves the ductility which is the exact opposite of what is required to maximize the elastic modulus and tensile strength. Finally, a multi-objective particle swarm optimization algorithm was used to obtain the non-dominated Pareto-optimal solutions that can lead to an optimal combination of the mechanical properties.

Microstructures and mechanical properties evolution of IN939 alloy during electron beam selective melting process

Microstructure formation and transformation during electron beam selective melting (EBSM) is a unique process that has rarely been investigated, but can significantly influence the mechanical properties of parts. In this study, defect-free IN939 superalloy specimens were prepared and characterized using the EBSM method. It was found that the microstructures of the EBSM IN939 specimens consisted of primary, middle, and coarse γ' phases, and the ƞ phases had a gradient attribute. Transmission electron microscopy, selected-area electron diffraction, and energy dispersive spectroscopy tests were performed at different specimen heights, as well as a series of tensile tests. The results showed that the yield strength was influenced by the gradient microstructure. Higher yield strengths were obtained at the top of the fabricated specimens. Post-treatment was adopted to homogenize the gradient microstructure. Fracture analyses after the tensile test demonstrated the effects of different strengthening phases on the fracture behavior.

New Grain Formation Mechanisms during Powder Bed Fusion.

Tailoring the mechanical properties of parts by influencing the solidification conditions is a key topic of powder bed fusion. Depending on the application, single crystalline, columnar, or equiaxed microstructures are desirable. To produce single crystals or equiaxed microstructures, the control of nucleation is of outstanding importance. Either it should be avoided or provoked. There are also applications, such as turbine blades, where both microstructures at different locations are required. Here, we investigate nucleation at the melt-pool border during the remelting of CMSX-4® samples built using powder bed fusion. We studied the difference between remelting as-built and homogenized microstructures. We identified two new mechanisms that led to grain formation at the beginning of solidification. Both mechanisms involved a change in the solidification microstructure from the former remelted and newly forming material. For the as-built samples, a discrepancy between the former and new dendrite arm spacing led to increased interdentritic undercooling at the beginning of solidification. For the heat-treated samples, the collapse of a planar front led to new grains. To identify these mechanisms, we conducted experimental and numerical investigations. The identification of such mechanisms during powder bed fusion is a fundamental prerequisite to controlling the solidification conditions to produce single crystalline and equiaxed microstructures.

Effect of different parameters on the tensile properties of printed Polylactic acid samples by FDM: experimental design tested with MDs simulation

Fused depositional modeling (FDM) is one of the common methods for 3D printing of polymers, which is expanding in various industrial applications, scientific researches, and engineering applications due to its ability to make complex parts. In this research, molecular dynamics (MDs) simulation has been used to predict the physical and mechanical properties. Then, the mechanical properties of the printed parts were determined. The mechanical properties of 3D printed parts strongly depend on the correct selection of processing parameters. In this study, the effect of three important parameters such as infill density, printing speed, and layer thickness were investigated on the tensile properties of PLA specimens. For this purpose, standard specimens with four infill densities of 20%, 40%, 60%, and 80%, two speeds of 20 mm/s and 40 mm/s, and two thicknesses of 0.1 mm and 0.2 mm were printed and tested under quasi-static tensile test. In all printed specimens, the print angle is ± 45°. The obtained experimental outcomes from the tensile test revealed that with increasing the infilling density, the mechanical properties of the parts improve and increase significantly. However, at very high infilling densities, the samples behave more brittle, so in cases where the strength of the part is less important than its shape and appearance, a density of 40% is more suitable in terms of cost, material, and time savings. It was also noted that the printing speed has less effect on the mechanical properties of PLA parts. It was also observed that reducing the thickness of the layer, while slightly increasing the stiffness of the parts, makes the part extremely brittle, and on the other hand, it leads to increase in the dimensional accuracy and surface quality of the specimens. At infill density of 80%, the specimens had the highest stiffness and strength, but it exhibits a brittle behavior. Moreover, it can be deduced that by reducing the layer thickness although the modulus of elasticity increases a little, ductility is greatly affected.

Multitemperature parameter optimization for fused deposition modeling based on response surface methodology

Fused deposition modeling (FDM) is an additive manufacturing technology that is extensively applied in engineering and medicine and offers a wide range of raw materials, low manufacturing cost, and personalized features. The mechanical properties of parts fabricated by FDM are greatly influenced by the multitemperature process parameter system. However, systematic research on the relationship between the multitemperature parameter system and mechanical properties of FDM parts is lacking. In this study, we used the response surface methodology (RSM) to optimize a multi-temperature parameter system of FDM to address the limitations of the commonly used conventional experimental method. The effect of temperature conditions (nozzle temperature, platform temperature, and environment temperature) on the tensile strength of the carbon fibers/polylactic acid composite specimens was systematically studied using the constructed RSM model. The RSM model was used to analyze and optimize the parameters of the multitemperature system for the optimal tensile strength, and the FDM experiment was carried out. The tensile strengths obtained using the FDM and response surface optimization were 32.4 and 31.35 MPa, respectively, with a gap of 3.2%. These results show that the RSM optimization method has a remarkable effect and can be used to optimize the multitemperature parameter system of the FDM.

Effect of Particle Size Distribution on Laser Powder Bed Fusion Manufacturability of Copper

One of the major benefits of the Laser Powder Bed Fusion (LPBF) technology is the possibility of fabrication of complex geometries and features in only one-step of production. In the case of heat exchangers in particular, this is very convenient for the fabrication of conformal cooling channels which can improve the performance of the heat transfer capability. Yet, obtaining dense copper parts printed via LPBF presents two major problems: the high reflectivity of 1 μm (the wavelength of commonly used laser sources) and the high thermal conductivity of copper that limits the maximum local temperature that can be attained. This leads to the formation of porous parts.In this contribution, the influence of the particle size distribution of the powder on the physical and mechanical properties of parts produced via LPBF is studied. Three copper powders lots with different particle size distributions are used in this study. The effect on densification from two laser scan parameters (scan speed and hatching distance) and the influence of contours scans on the lateral surface roughness is reported. Subsequently, samples manufactured with the optimal process parameters are tested for thermal and mechanical properties evaluation.

Mechanical Property and Prediction Model for FDM-3D Printed Polylactic Acid (PLA)

Fused deposition modeling (FDM) has been the preferred technology in 3D printing due to its ability to build functional complex geometry parts. The lack of the printing parameter information and prediction model that directly reflects towards 3D printed part's mechanical properties has been a barrier for the FDM 3D printer users to appraise the product's strength as a whole. In the present work, 27 tensile specimens with different parameter combinations were printed using a low-cost FDM 3D printer according to the ASTM standard to evaluate their tensile properties. Statistical analysis was performed using MINITAB to validate the experimental data and model development. The investigational outcomes reveal that ultimate tensile strength was primarily affected by infill density, whereby it increases with increasing infill density. Elastic modulus, fracture strain, and toughness were mainly affected by infill density and layer thickness. The ideal printing parameter for optimal tensile behavior was identified to be 0.3 mm layer height, 40° raster angle, and 80% infill density from the 9th combination. The tensile values obtained for the optimal printing parameter were 28.45150 MPa for ultimate tensile strength, 0.08012 mm/mm for fracture strain, 828.06000 MPa for elastic modulus, 20.19923 MPa for yield strength, and 1.72182 J/m3 for toughness. The statistical analysis further affirmed the optimum printing has a minimal deviation from the experimental response. Finally, a mathematical model is proposed for the tensile properties prediction.

Effect of Al powder on mechanical properties and microstructure of wood-plastic composites by selective laser sintering

To solve the problem of the low mechanical properties of wood-plastic composites (WPC) by selective laser sintering (SLS), a tiny amount of Al powders were added into WPC as the reinforcement in this work. Both the mechanical properties and the microstructure of SLS parts were investigated. The results showed that the bending properties of parts first increased to 128.08 % and then decreased to 118.1 % with the increase of Al powder content from 0.1 wt% to 2 wt%. The porosity and sintering neck size of fracture had the same change pattern as the mechanical properties of parts. The strengthening mechanism might be that the good thermal conductivity of Al powder would better facilitate the sintering behavior of composite powder and a stronger interface bonding between wood powders and PES matrix can be obtained. However, the mechanical properties of SLS parts with excessive Al powder decreased due to its reflecting lasers.

Experimental study of resin coating to improve the impact strength of fused filament fabrication process pieces

Purpose This study aims to evaluate the impact breaking energy of the parts manufactured by the fused filament fabrication (FFF) method. The evaluation considers the use of the epoxy resin coating, different materials and different printing orientations. Design/methodology/approach The authors developed an experimental statistical design using 54 experimental trials. The experiments’ output variable is the impact break energy of the parts manufactured by the FFF method. The input variables for the experiments consist of an epoxy resin coating (XTC-3D®, generic resin and without resin coating), different filament materials (nylon + carbon fiber, polyethylene terephthalate and polycarbonate) and different printing orientations (flat, edge and vertical) used. The authors carried out the tests following the EN ISO 179-1. Findings The use of resin coating has a significant influence on the impact energy of parts manufactured using the FFF method. The resin coating increases the impact resistance of parts processed by FFF by almost 100% of the value as compared to the parts without a resin coating. Post-processing is useful on ductile materials and increases impact breaking energy at weak print orientations. Originality/value This research opens a new opportunity to improve the mechanical properties of parts manufactured using the FFF method. The use of a resin coating reinforces the parts in weak print orientation.

Investigation on the ageing behaviour and hardening mechanisms of 5A90 Al–Li alloy U-shaped parts formed by electric resistance heating forming-quenching process

The electric resistance heating technology was introduced into the solution heating, forming-quenching with cold die integrated process for improving the dimensional accuracy of the 5A90 Al–Li alloy U-shaped parts. In order to evaluate the effect of current density on the forming quality of U-shaped parts, the springback and mechanical properties of formed parts were analyzed. The dimensional accuracy of formed parts increased with the current density. The U-shaped part with the minimum springback angle (0.43°) was obtained under the current density of 12.76 A/mm 2 . The increase in hardness of the typical positions of U-shaped parts was mainly due to the spherical δ′ phase with the proper matching of volume fraction and size. The hardness of the bottom fillet increased from 82.4 HV to 113.53 HV after ageing at 160 °C for 10 h. A mechanistic model referring to grain boundaries, dislocation accumulation, solid solution and precipitation was established to describe the hardening mechanisms. The δ′ phase not only contributed to the precipitation hardening mechanism but also affected the solid solution hardening by changing the concentration of solute atoms. The precipitate hardening caused by δ' phase with the perfect antiphase boundaries was the dominant mechanism, which afforded 35.6 HV with the volume fraction of 31.51% in the peak-aged sample. • The EHFQ process improves the dimensional accuracy of the 5A90 Al-Li alloy U-shaped parts. • The precipitation behavior and matching relation of δ′ phase are studied, which affect the mechanical properties of parts. • A mechanistic model is established to describe the hardening mechanisms and the contribution of each mechanism is analyzed.