Papers by Keyword: Powder Metallurgy

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Authors: Chun Ming Wang, Si Yu Gao, Su Fen Xiao, Yun Gui Chen
Abstract: In-situ formation of nanometric TiC reinforcements based on Ti matrix composites were researched by a novel preparation method, which including glucose polymers coating and powder metallurgy. The results showed that TiC nanoparticles were homogeneously distributed in Ti matrix, and the as-sintered Ti-TiC composites displayed excellent compressive properties which ultimate compressive strength was 2500 MPa, yield strength was 1450 MPa and strain to fracture was 53 %.
Authors: Ehsan Sharifi Sede, Shamsedin Mirdamadi, Hossein Arabi
Abstract: This study sought to create a biocomposite of Magnesium and Titanium via a powder metallurgy technique. Powder metallurgy technique was used to produce three different volume percentages of Magnesium (30% , 35% , 40%). Titanium powder was mixed with Magnesium, then the samples were compressed by 1800 Bar using a cold, isostatic press process. The samples were then sintered to 850 for 100 min. At this temperature, the compressive yield strength was increased to 210 Mpa and significantly depended on the volume percent of Magnesium present, the core size and temperature of sintering. The bioactivity of the samples in a simulated body fluid (SBF) was also investigated. When the samples were immersed in the simulated body fluid for a 14 and 28 days, calcium and other elements were found to be deposited on the surface. Additionally, it was found that TiO2 has the ability to induce the formation of bone-like apatite in the SBF. In addition, the degradation product of Magnesium in a biological system caused a rise in the pH and environment for the deposition of calcium and other element on the surface were enhanced. Finally, the samples were analyzed using XRD, EDS, and optical and scanning electron microscopy (SEM).
Authors: Sravan Kumar Josyula, Suresh Kumar Reddy Narala
Abstract: Aluminum based Titanium carbide particulate reinforced metal matrix composite (Al-TiC PMMC) draws attention by many researchers & industries over alloy materials because of its excellent thermo-physical and mechanical characteristics. Despite of its superior properties of Al-TiC MMC, its complexity in manufacturing process and poor machinability has been the main deterrents to its application level. Controlling agglomeration of TiC particles is a challenging task to retain improved microstructure. The hard abrasive nature of carbide particles cause poor machinability and high machining cost. Therefore, in this paper an attempt has been made to study the various manufacturing techniques to achieve uniform distribution of TiC reinforcements in Al matrix.Further, the review follows the secondary manufacturing process of Al-TiC PMMC, which addressee’sthree topics: machining, forming & welding.
Authors: Arne Biesiekierski, James Wang, Cui'e Wen
Abstract: In the realm of bioimplantation, titanium-based Shape Memory Alloys (SMAs) exhibit phenomenal versatility, with successful application in diverse fields. One area of particular interest is that of orthopaedics, where the unique properties of SMAs offer a range of benefits. That said, existing alloys still have unresolved issues concerning biocompatibility and osseointegration. Primary concerns include carcinogenicity, allergenicity and a significant mismatch between the Young’s moduli of bone and osteoimplants; issues that could be addressed via a novel porous titanium alloy. With that in mind, this paper seeks to provide a review identifying promising candidates for new, perfectly biocompatible alloys for production via powder metallurgy. Furthermore, an attempt will also be made to summarise existing research into appropriate methods for the production of a porous Ti-based SMA implant.
Authors: Attanadol Prapajaraswong, Seksak Asavavisithchai
Abstract: Al foam is an advanced engineering material with many outstanding properties, such as very low density, high specific strength and stiffness, and large energy absorption. In the present study, pure Al foams were mixed with either cenosphere or precipitator fly ash particles of various contents. Fly ash particles are used in Al foams as reinforcement and stabilising materials which enable the foams with large expansion. It is found that Al foams with precipitator fly ash particles of various contents exhibited larger expansions than the foams with cenosphere fly ash particles. The quantitative analysis also revealed that more stable foam structure was obtained in Al foams with precipitator fly ash addition.
Authors: Muziwenhlanhla A. Masikane, Hilda K. Chikwanda, Iakovos Sigalas
Abstract: Over the past years, the blended elemental powder metallurgy (PM) approach has been identified as one of the most promising strategies to reduce the cost of titanium-based components. However, oxygen pick-up, inhomogeneity of the microstructure and chemical composition are sometimes reported for PM parts. This work compares properties of a blended elemental Ti-6Al-4V alloy obtained by sintering under argon gas atmosphere with those of a vacuum cast alloy. Argon was purified by passing it through a series of oxygen and moisture traps prior to being introduced into the sintering furnace. Casting was performed under vacuum (1 x 10-3 mbar). The starting material in both processes was the cold isostaticaly pressed blended elemental (BE) Ti-6Al-4V powder compact. The BE powder was prepared by mixing 60Al-40V master alloy powder with commercial Grade 4 titanium powder (0.377 wt.% O2). The sintered and cast alloys were compared on the basis of oxygen pick-up, density, microstructure, chemical composition and hardness to determine which method is better. Although the BE approach could not eliminate the common challenges associated with powder metallurgy processing of Ti alloys, oxygen pick-up and additional contamination was lower compared vacuum casting. Sintering at 1350°C for 1 h could not achieve full density compared to casting, but the microstructure appeared more homogeneous. Both sintered and cast Ti6Al4V alloys were harder than wrought Ti6Al4V due to a high concentration of interstitial oxygen. The sinterered and sintered plus HIPed Ti6Al4V alloys were softer than as-cast Ti6Al4V due to lower oxygen pick-up and incomplete densification. From the contamination and homogeneity perspective, the BE approach is an attractive technique for processing of Ti6Al4V alloy.
Authors: Ying Ying Sun, Shu Dong Luo, Ya Feng Yang, J.F. Sun, Ma Qian
Abstract: Powder metallurgy (PM) of titanium hydride (TiH2) has emerged as an attractive alternative to PM of Ti. Microwave (MW) heating has the potential to further facilitate the development of PM TiH2 as TiH2 is essentially a ceramic material. A detailed assessment has been made of the effectiveness of MW heating of Ti-xTiH2 (x =0-100) powder compacts through 30 experiments conducted under a variety of conditions. MW hybrid heating (i.e. when assisted with a SiC MW susceptor) proved to be reliable and consistent in heating Ti-xTiH2 powder compacts and the heating rate increased progressively with increasing TiH2 powder content, indicating that TiH2 powder is more responsive to MW heating than Ti metal powder. However, heating of TiH2 powder compacts by MW radiation without the assistance of a SiC MW susceptor proved to be inconsistent and unpredictable, where successful heating (heated to 1300°C in 20 min) was achieved but many failures also occurred. However, the use of SiC can cause contamination (Si and C). The challenges of heating of TiH2 powder by direct MW radiation were discussed.
Authors: Ali Lahouel, Said Boudebane, Alain Iost, Alex Montagne
Abstract: The aim of this research paper is to fabricate a Fe-TiC composite by a novel and simple manufacturing method. The latter is based on two cumulative processes; a conventional sintering (transient liquid phase sintering) and a hot forging with steam hammer respectively. The blinder phase of the studied simples is varied from carbon steel to high alloy steel using alloying additive powders. The obtained outcomes showed that after the sintering process, the relative density of the performed simples is improved from 86% to 95.8% without any densification process. Otherwise, in order to ensure maximum densification and enhance in addition the solubility of the alloying additives the hot forging process is then applied. Indeed, the final obtained composite product is a TiC-strengthened steel with a relative density around 99% (about 6.5 g/cm3 of density) wherein 30% (wt.) of spherical and semi-spherical TiC particles are homogeneously distributed in the metal matrix.
Authors: Alessandra A.A. Santos, U.U. Gomes, M. Furukava
Abstract: Extensive work has been performed on WC-Co hard metals for mining tools, tool inserts and other components. Cobalt is widely used as the binder metal because it’s good wetting behavior and solubility. However, the cost is high. Fe-Cr-Ni alloys show similar characteristics to Cobalt regard to melting temperature and crystal structure. Additionally, Fe-Cr-Ni alloys are a less expensive and nontoxic alternative. The present work analyze sintering characteristics of the WC / Fe-Cr-Ni alloys composite and development of new sintered hard metal composite for mining tools. The composite WC-316L was processed via Powder Metallurgy and sintering was performed at different temperatures: 1200oC, 1300oC and 1400oC rate and 20oC and isotherm 1hour in vacuum atmosphere. The composite sintered WC-316L was characterized by XRD, SEM and Vickers micro hardness test. The samples processed at temperatures of 1200oC and 1300oC showed considerable porosity, heterogeneity microstructure, low density relative and low Micro hardness, 300 HV and 700 HV, respectively. The samples sintered at temperature 1400oC showed higher homogeneity microstructure compared to the samples sintered at temperatures of 12000C and 13000C, higher density relative, 86%, and micro hardness value compatible with the composite WC-Co, 1890 HV.These analyzes infer that stainless steel can be used instead of cobalt.
Authors: Chakravarthi Parswajinan, B. Vijaya Ramnath, M. Vetrivel, P. Ramanarayanan, S. Bharath, T. Ajay, R. Raghav Chander
Abstract: Carbon nanotubes are the latest trends in the study of powder metallurgy and nanocomposites. This is due to the exceptional properties like superior mechanical and electrical properties, high Young’s modulus, high tensile strength, smaller diameters, high elongation and high chemical stability. CNT’s is an attractive reinforcement for metal matrix composites. CNT are now reinforced with many metal matrix composites like aluminium, iron, manganese, copper etc. with considerable change in density of the material. Due to high aspect ratio that facilitates their tubular structure and high strength the CNT’s are reinforced with ferrous powder by implying powder metallurgy process and the results have been recorded. Such recordings of the effects of CNT on Ferrous powders are reviewed in this paper.
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