Powder Metallurgy Method Research Articles

The Manufacturing Process and Corrosion Properties of Magnesium Matrix Composites: A Review

Magnesium-based biomaterials are a new generation of biodegradable metals that are playing a major role in the development of future implant materials. Magnesium-based materials can corrode too rapidly during physiological conditions and lose their usefulness before bones heal. This review aims to provide a comprehensive overview of the selection of suitable matrix and reinforcing materials as well as suitable process techniques to achieve better corrosion resistance targeted for dental implant applications. It also discusses the advantages and disadvantages of testing methods and corrosion media commonly used for biomedical applications. Specific search strategies are carried out in electronic databases: Springer, Pubmed, and Sciencedirect as well as google without limiting years. Papers are selected after reviewing their title, abstract, and full text. Then study the objectives, criteria, methods, and results. Based on the available literature, we can conclude that for magnesium-based composite matrices it is preferable to use commercially available Mg AZ91D alloys to investigate their corrosion behavior in vitro and in vivo environments. While for the composite reinforcement, bioceramic materials can be used, including Hydroxyapatite (HA) added with Zirconia ceramics (ZrO2) or Titanium metal oxide (TiO2). Furthermore, the process of making ceramic composites uses powder metallurgy (PM) and squeeze casting methods. Then, corrosive testing can use the commonly used electrochemical methods, namely Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) with corrosive SBF media.

Investigation of Mechanical Properties of Ti6Al4V Alloy Foams produced by Powder Metallurgy Method

In this study, it was aimed to production titanium alloy implants, which are widely used in the biomedical industry, as foamed materials under different mechanical alloying and sintering conditions using the powder metallurgy method Tİ6Al4V alloy is good mechanical properties, good biocompatibility properties and good corrosion resistance used as hard tissue replacements and implants. Similar mechanic properties with bone are expected from the implant to work coherently for long cycles of use and without any failure. Especially, elastic modulus of implant must be similar with bones, if not, some damages at bone surface and fallowing repeats of implant surgeries are reported. This situation has a destructive effect on health, finance, and comfort of the patient/user of the implant. In this study, powder metallurgy and space holder removal methods were used to produce porous Ti6Al4V specimens. Throughout the project study different space holder materials and binder agents were used. As weight percent, 20%, 30%, 40%, 60%, 70%, 80% porous specimens were pressed at uniaxial press machine, and sintered to the 850 ºC at argon atmosphere in furnace to reduce the oxidation to the level as low as possible. The E-Modulus values of the specimens reached the desired values with increasing porosity. It was obtained as 88 MPa in the specimen with 80% porosity, decreasing inversely proportionally, especially from the 60% porosity rate.

Production of AA 2014 Matrix Wollostanite/Wood Ash Solid Waste Particle Reinforced Hybrid Composite with Powder Metallurgy and Investigation of Its Structural Properties

In this study, using AA 2014 aluminum alloy, AA2014/wollastanite, AA2014/wood ash, and AA2014/wollastanite/wood ash composite hybrid materials were produced by powder metallurgy method. The powders, whose mixing ratios were determined by weight, were mixed in a 3-dimensional mixer for 30 min. The prepared mixture powders were pressed uniformly under a pressure of 700 MPa, and cylindrical materials with a diameter of 10 mm were obtained. Then, the materials were sintered for 1 h under argon gas flow at a temperature of 600°C. The density, microstructure, hardness, and wear behavior of the materials were examined. It was observed that the density of the composite materials increased relatively compared to AA 2014 alloy. As the particle reinforcement ratios increased, porosity amounts also increased in the composite and especially in the hybrid materials. In the wood ash-reinforced composite materials, the particles were distributed more homogeneously in the microstructure. The highest hardness value obtained was 70.65 HV in AA2014/15% wollastanite composite material. The weight loss increased in the materials created by particle reinforcement, and the lowest weight loss (170 mg) was determined in this material.

Scope of magnesium ceria nanocomposites for mandibular reconstruction: Degradation and biomechanical evaluation using a 3-dimensional finite element analysis approach

Magnesium/Ceria nanocomposites (Mg/xCeO2 NCs (x = 0.5 %, 1 % and 1.5 %)) prepared by using powder metallurgy and microwave sintering method are assessed for their corrosion rate for a period of 28 days. As per the immersion tests results, the addition of ceria nanoparticles to pure Mg, brought about a noteworthy improvement to corrosion resistance. A corrosion rate of approximately 0.84 mm/year for Mg/0.5CeO2 and 0.99 mm/year for Mg/1.0CeO2 nanocomposites were observed. Another aspect of the study involves employing the simulation method i.e. finite element analysis (FEA) to compare the stress distribution in magnesium-ceria nanocomposite based screws and circular bars especially for Mg/0.5CeO2 and Mg/1.0CeO2. Further, the simulation also gives a perception of the impact of masticatory forces, the biting force and shear stress exerted on the Mg/0.5CeO2 and Mg/1.0CeO2 based screws. The simulations results show that the screws showed an acceptable level of stresses for a biting force up to 300 N. The circular bar as well kept its stresses at acceptable levels for the same load of 300N. The shear stress results indicated that a biting force up to 602 N can be safely absorbed by Mg/0.5CeO2 screw. The comprehensive approach allows for a better understanding of the corrosion behavior, stress distribution, and mechanical properties of the Mg/CeO2 nanocomposites, enabling the development of effective temporary implants for craniofacial trauma fixation that can withstand normal physiological forces during mastication. The study reported in this paper aims to target Mg/xCeO2 NCs for temporary implants for craniofacial trauma fixation.

In situ Implanting 3D Carbon Network Reinforced Zinc Composite by Powder Metallurgy for Highly Reversible Zn-based Battery Anodes.

Aqueous Zn-based batteries have emerged as compelling candidates for grid-scale energy storage, owing to their intrinsic safety, remarkable theoretical energy density and cost-effectiveness. Nonetheless, the dendrite formation, side reactions, and corrosion on anode have overshadowed their practical applications. Herein, we present an in situ grown carbon network reinforcing Zn matrix anode prepared by powder metallurgy. This carbon network provides an uninterrupted internal electron transport pathway and optimize the surface electric field distribution, thereby enabling highly reversible Zn deposition. Consequently, symmetrical cells demonstrate impressive stability, running for over 880 h with a low voltage hysteresis (≈32 mV). Furthermore, this Zn matrix composite anode exhibits enhanced performance in both the aqueous Zn-ion and the Zn-air batteries. Notably, Zn//MnO2 cells display superior rate capabilities, while Zn-air batteries deliver high power density and impressive Zn utilization rate (84.9 %). This work provides a new idea of powder metallurgy method for modified Zn anodes, showcasing potential for large-scale production.

In situ Implanting 3D Carbon Network Reinforced Zinc Composite by Powder Metallurgy for Highly Reversible Zn‐based Battery Anodes

AbstractAqueous Zn‐based batteries have emerged as compelling candidates for grid‐scale energy storage, owing to their intrinsic safety, remarkable theoretical energy density and cost‐effectiveness. Nonetheless, the dendrite formation, side reactions, and corrosion on anode have overshadowed their practical applications. Herein, we present an in situ grown carbon network reinforcing Zn matrix anode prepared by powder metallurgy. This carbon network provides an uninterrupted internal electron transport pathway and optimize the surface electric field distribution, thereby enabling highly reversible Zn deposition. Consequently, symmetrical cells demonstrate impressive stability, running for over 880 h with a low voltage hysteresis (≈32 mV). Furthermore, this Zn matrix composite anode exhibits enhanced performance in both the aqueous Zn‐ion and the Zn‐air batteries. Notably, Zn//MnO2 cells display superior rate capabilities, while Zn‐air batteries deliver high power density and impressive Zn utilization rate (84.9 %). This work provides a new idea of powder metallurgy method for modified Zn anodes, showcasing potential for large‐scale production.

Large area hole defect repair of titanium alloys by powder pressing and vacuum sintering

A simple and efficient powder metallurgy method to repair the large area hole defect of titanium alloys was addressed in this work. The titanium-based powder mixture was pressed in the defect area by cold isostatic pressing and then sintered at elevated temperature. Three powder systems Ti–Ni/Ti–Sn/Ti–Ni–Sn were chosen according to liquid phase sintering theory. Ti–7Ni–5Sn powder system led to better densification and interface bonding by sintering at 1200 °C. After repair, the strength reached more than 95 % that of the Ti–6Al–4V matrix.

Microstructural and mechanical behavior of second-phase hardened porous refractory Ti-Nb-Zr-Ta alloys

Second-phase hardening in refractory high-entropy alloys (RHEAs) has been recognized as one of the main routes to significantly improve their mechanical properties. However, their costbenefit should not be compromised. Thus, we designed second-phase strengthened RHEAs by a low-cost powder metallurgy method. We induced the formation of FCC (face-centered cubic) ZrC second phase, which has not been reported in Ti-Nb-Zr-Ta alloys before and may be easily confused with the FCC-Zr due to the complexity of identifying carbon by conventional methods. We used neutron diffraction and electron backscatter diffraction for microstructural studies, as well as hardness, ultrasonic and compression techniques for assessing mechanical properties. Our investigation centered on equiatomic and equimassic Ti-Nb-Zr-Ta alloys, both displaying similar grain morphology and porosity but differing in grain sizes and phases. The variation in grain size was attributed to the influence of Ta as a grain growth pinning element. Our second-phase ZrC hardened alloys revealed higher stiffness and hardness, surpassing those documented in the existing literature.

Effect of nano-sized Mo particles on microstructure and mechanical properties of Mo/AZ31 composites

It is a challenge to enhance both strength and ductility for the Mg matrix composites. In the present work, nanostructured Mo-reinforced AZ31 composites are synthesized via powder metallurgy method. The addition of nano-sized Mo particles reduces the grain size and decreases the texture strength of the composites. The Al5Mo and Al8Mo3 phases are formed through Al atoms diffusion and interaction with Mo atoms. The synergistically reinforcing effect of Al5Mo, Al8Mo3 and nano-sized Mo particles improves the mechanical properties of the composites. The nano-Mo/AZ31 composite with 1.0 wt% Mo addition exhibits superior mechanical properties, with yield strength, ultimate tensile strength, and elongation of 221 MPa, 328 MPa and 12.4 %, respectively. These results mean the improvements of 20.1 %, 17.1 % and 21.6 % compared to the AZ31 Mg alloy. The strength enhancement is attributed to the grain refinement and Orowan strengthening, while the improvement in ductility is attributed to grain size reduction, texture weakening, and the activation of a broader range of slip systems.

The role of SiCw in the microstructure and properties of WC-9Co gradient cemented carbide

Powder metallurgy method was used to prepare WC-9Co gradient cemented carbide with various amounts of SiC whiskers (SiCw). The microstructure and properties of WC-9Co-SiCw gradient cemented carbide were studied. The thickness of gradient layer, metallographic structure and phase composition were investigated by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Vickers indenter, universal testing machine, tribometer and grazing incidence X-ray diffraction (GIXRD) were used to test the hardness, fracture toughness, bending strength, wear resistance and surface oxidation resistance of the specimens. According to the results, an appropriate addition of SiCw inhibited the growth of WC grains and facilitated the formation of the gradient layer. The relative density, hardness, fracture toughness and bending strength increased firstly and then decreased with the addition of SiCw. Furthermore, the wear resistance and surface oxidation resistance were improved by SiCw. However, an external addition of SiCw would adversely affect on sintering capability of WC-9Co-SiCw cemented carbide and decrease their comprehensive properties.

Mechanochemical synthesis, purification, and optimization studies of Cr boride@MgO particles

Chromium boride, an advanced ceramic material, is commonly produced by powder metallurgy methods using elemental boron and chromium powder, borothermic reactions, or boron carbide reduction of Cr2O3. In this study, a mechanochemical method for the production of chromium boride was developed, subsequent purification was performed, and the whole process was optimized. The amounts of Cr2O3, B2O3, and Mg in the initial powder blends were determined by computational thermodynamic methods based on their equilibrium compositions. Firstly, stoichiometric starting-powder blends were milled at different durations (1, 2, 3, 4, 5, and 8 h). The optimum purification route was determined using acid leaching experiments carried out with different acids, at different temperatures, and concentrations. Secondly, powders prepared in excess amounts were synthesized at the optimum duration (5 h) and leaching condition (0.1 M HCl, 25 °C). For the 100 wt % excess B2O3, 25 wt % excess Mg and 0.8 moles of Cr2O3 composition, annealing was conducted at 1100 °C. Characterization studies, X-ray diffractometry (XRD), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM), and atomic absorption spectroscopy (AAS) were conducted on the milled and leached powders. After annealing, CrB, CrB2, Cr3B4 and MgO phases were obtained in the XRD patterns. The particle sizes of the resulting materials were also analyzed, and it was found to be nearly 3.11 μm after annealing. Finally, the TEM analysis revealed that the MgO peak evident in the XRD patterns was MgO shell covering the Cr boride particles having submicron sizes; hence, a pure Cr boride@MgO core-shell structure was obtained.

Comparative Analysis of Tribological Behavior in Aluminum Matrix Composites Incorporating Fe75Si15Zr5B5 Metallic Glass and SiC Particles

In this study, a comparative investigation was conducted to assess the impact of Fe-based metallic glass (FMG) and silicon carbide (SiC) reinforcing particles on the tribological properties of aluminum matrix composites. The composites were synthesized using the powder metallurgy method, and subsequent dry sliding wear tests were performed by a pin-on-disc machine at ambient temperature. Thorough examinations of the microstructure, mechanical properties, and densification behavior were carried out for the developed composites, and these findings were then correlated with their wear performance. To gain insights into the wear mechanisms, comprehensive characterizations of the worn surfaces and debris were conducted utilizing field-emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDS) analysis. The outcomes of the dry sliding tests revealed that, in contrast to SiC, the addition of FMG reinforcing particles significantly decreased the friction coefficient while concurrently enhancing the wear resistance of the aluminum matrix. The microstructural investigations divulged that the pure aluminum sample experienced severe abrasive and adhesive wear mechanisms, which were effectively mitigated through the incorporation of FMG particles, due to the formation of an oxide tribolayer in the composite during the wear test. Conversely, the SiC-reinforced composites exhibited a dominant wear mechanism characterized by severe delamination, which consequently contributed to their elevated wear rate. These findings shed light on the distinct effects of FMG and SiC particles on the tribological properties of aluminum matrix composites, providing valuable insights for potential applications in engineering and industrial sectors, particularly in scenarios involving metal-to-metal contact.

Valorization of waste from old gold mining in the south of the Russian Far East using pyro-hydrometallurgy methods

The basics of the original technology for the development of man-made placers in the south of the Russian Far East have been developed. The necessity of using methods of hydrodifluoride conversion, hydrometallurgy, fluoride autopsy is substantiated. To create an environmentally safe resource-saving technology for the enrichment of man-made formations, methods of powder metallurgy, leaching of raw materials by liquid extraction with simultaneous demercurization, as well as fluoride autopsy are used. The application of this scheme for extracting useful components from placer material will allow the industrial turnover of numerous man-made placers in compliance with resource-saving principles and without causing significant damage to the environment.

Investigation the Effect of TiC on Some Properties of ZA-27 Alloy Prepared By Powder Metallurgy Method

Investigation the Effect of TiC on Some Properties of ZA-27 Alloy Prepared By Powder Metallurgy Method

Microstructure investigation of light weight Al/Si/Ni hypoeutectic material prepared by powder metallurgy method

In this study, the researchers examined the impact of adding different percentages of nickel (0 %, 0.01 %, 0.05 %, 0.1 wt%) to an aluminum-silicon (Al-Si) alloy. Aluminum alloys are widely used in various industries due to their lightweight nature and favorable mechanical properties. The microstructure of the alloy was analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM) tests.The XRD and SEM analyses revealed that the Al-Si alloy consisted of two phases: α-Al and Si. The introduction of nickel resulted in the detection of an intermetallic compound (IMC) known as Al3Ni. This IMC caused changes in the lattice constant and interatomic spacing (dhkl). The observed distortions and densification in the microstructure were identified as indicators of increased hardness and strength in the alloys. The researchers attribute this enhancement in microstructure properties to the elevated temperature, which facilitated greater diffusion of nickel atoms into the aluminum lattice.

The effects of periwinkle shell reinforcement in a grey cast iron metal matrix composite (using powder metallurgy)

Grey cast iron is widely used in various engineering applications because of its cost effectiveness and beneficial properties. However, due to the presence of graphite in its microstructure its capacities are limited. Various engineering methods such as compositing are researched into that may minmize these limitations and give the metal a wider scope of application. In this project, periwinkle shell reinforced grey cast iron composites were manufactured using the powder metallurgy method. The weight percentage of periwinkle shell in the composite was varied in the following pattern: 5 %, 10 %, 15 %, 20 % and 25 %. The manufactured samples were subjected to various tests namely: wear test, hardness test, tensile test, impact test and compressive test. It was observed that the reinforcing grey cast iron with periwinkle shells improved the wear rate, tensile strength and impact toughness of the matrix but has adverse effects on its hardness and compressive strength.

High‐Pressure Torsion: A Simulation Approach for Additive Friction Stir Deposition Processes

The technology of manufacturing aluminum alloy workpieces using additive friction stir deposition (AFS‐D) has been thoroughly investigated. The ambiguous influence of deformation processing modes on the material density was found. Examination of the microstructure in the central zone of the specimens reveals the absence of microdefects typically associated with workpieces obtained through casting or powder metallurgy methods. It has been observed that the distribution of microhardness is significantly affected by the direction of specimen construction, with approximately a 20% difference in values between the periphery and the central part of the specimen. Specimens produced using the AFS‐D method exhibit a homogeneous microstructure characteristic of deformable aluminum alloys. Notably, a uniform distribution of intermetallides on the specimen surface has been identified. This outcome is likely a result of the alloy undergoing recrystallization during the severe plastic deformation process, leading to the formation of an ultradisperse structure. It is important to emphasize that the selection of technological parameters for AFS‐D should consider not only the magnitude of pressure and deformation but also the deformation speed.

Synthesis of Y2O3 and graphite-added copper-based hybrid composites by powder metallurgy: Mechanical properties and tribological behavior

In the presented study, Y2O3 and graphite-reinforced Cu matrix hybrid composite materials were prepared using the powder metallurgy method. The aim is to compare the microstructure, density, hardness, and wear behavior of composites with different yttria contents (5, 10, and 15 weight%) and graphite (2 weight%) reinforcements. An increase in the Y2O3 ratio, along with the addition of graphite, resulted in an observed increase in the hardness values of the composites. Additionally, it was observed that Y2O3 and graphite are homogeneously distributed in the copper matrix in the SEM-EDX spectra. Upon examining the microstructures of the composites, it was determined that with the increase in yttrium oxide content, partially yttrium oxide agglomerations formed in some regions. The addition of Y2O3 resulted in a copper sample that is 1,34 times harder than pure copper. Addition of Y2O3 -graphite, samples with 3.301-22.3 % higher wear resistance were obtained.

Investigation of the Formation of Structure and Properties in a Billet Made of Heat-Resistant Nickel Alloy EP741NP, Obtained by Hot Isostatic Pressing Technology

It is known that the technology of hot isostatic pressing (HIP) can reduce the residual porosity and increase the level of physical and mechanical characteristics of products obtained by powder metallurgy methods. In modern aircraft and rocket engineering, heat-resistant heterophase nickel alloys are used, which are obtained with the use of granular metallurgy. This material is indispensable in the creation of disks of gas turbine engines (GTE), which are part of the turbine rotor and serve to install the blades. Obtaining a nonporous product made of EP741NP alloy using the HIP technology will increase the service life of the turbine disks, which is an urgent task at the present time. The aim of the work is to study the structure and physical and mechanical properties of a billet made of heat-resistant nickel alloy EP741NP obtained by the HIP method at a temperature of 1150 °C. The starting material for the preparation of the workpiece is a metal powder EP741NP, obtained by gas atomization and having a fractional composition of 20...50 microns. It is shown that the HIP process at a temperature of 1150 °C makes it possible to obtain an optimal combination of physical and mechanical properties. Based on the obtained images of powder particles and the microstructure of the work piece, the shape of the particles of the powder under study, the main category of powder granularity was determined and digital porosity analysis of the workpiece under study was performed in the Thixomet Pro software package. The changes in density and hardness along the section of the work piece were also evaluated. It has been established that at a temperature of HIP 1150 °, the average porosity is insignificant and is 0.1 %, however, as we move away from the edge of the workpiece to its center, there is an increase in the content of pores, the size of which lies in the range of 1...20 microns. It is shown that during the technological process of HIP, an arched effect is observed, the consequence of which are overestimated characteristics of microhardness and density at the edge of the work piece.

STUDY OF THE POSSIBILITY OF INCREASING THE PLASTICITY OF TUNGSTEN WIRE AT NORMAL TEMPERATURES BY OPTIMIZING THE DRAWING TECHNOLOGY

Purpose. The development of a mathematical model for the process of drawing a tungsten-thorium wire for the analysis of the influence of technological factors of the specified process on the plasticity of the material and the recommendations on how to choose their optimal values, from the point of view reaching the plasticity of the wire at the maximum productivity of the wire drawing process.
 Research methods. The problem of creating a mathematical model for investigating the influnce of technological parameters into the process of drawing on the plasticity of a tungsten-thorium rod was considered to be based on the theory of experiment, in particular the method of experiment planning. Various material samples were prepared using methods of powder metallurgy and pressure treatment, in particular wire drawing. Experiments were carried out in real production conditions using industrial equipment. The plasticity of the tungsten-thorium rod was determined by torsion testing using the K-5 machine.
 Results. A mathematical model has been created that adequately describes the impact of technological factors on the plasticity of tungsten wire, which allows thoroughly analyze the physical processes that occur during wire drawing, and, if necessary, correct regimes without conducting a large number of physical experiments.
 Scientific novelty. The mathematical model has been proposed as it allows to analyze the impact of technological factors of drawing process on plasticity of tungsten-thorium wire produced at real manufacturing.
 Practical value. It can be useful for the technologists for higher productive application of industrial equipment and decrease of expenses for production of experiment consignment.