Identification of Cr and Cr2Nb precipitates in as-melt-spun Cu-Cr-Nb ribbons

1988 ◽  
Vol 46 ◽  
pp. 784-785
Author(s):  
D. L. Ellis ◽  
G. M. Michal
Keyword(s):  
Melt Spinning ◽  
Elevated Temperatures ◽  
Pure Copper ◽  
Intermetallic Phase ◽  
Copper Matrix ◽  
Surface Velocity ◽  
Induction Melting ◽  
Alumina Crucible ◽  
Aerospace Applications ◽  
Graphite Susceptor

A material with high thermal conductivity and mechanical strength at elevated temperatures is required for certain aerospace applications. Copper based alloys precipitation hardened with near zero solubility phases are candidate materials. Utilizing rapid solidification technology, elements such as Cr and Nb can be dissolved into liquid copper and fully precipitated out in the solid state. However, such elemental precipitates readily coarsen at elevated temperatures. The aim of this work was to create a more stable refractory metal intermetallic phase, C2Nb, in an essentially pure copper matrix via melt spinning.Ribbon was produced by induction melting a master alloy in an alumina crucible with a hole diameter of 1 mm (0.040-inch) using a graphite susceptor under an argon atmosphere. The alloy was heated to 1593°C (2900°F)and ejected onto a Cu wheel with a surface velocity of 20 m/s using a pressure of 0.07 MPa (10 psi). The resulting composition of the ribbon was 1.95 a/o Cr and 0.48 a/o Nb as determined by bulk spectrographic analysis.

scholarly journals New Zn3Mg-xY Alloys: Characteristics, Microstructural Evolution and Corrosion Behavior

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2505
Author(s):  
Catalin Panaghie ◽  
Ramona Cimpoeșu ◽  
Bogdan Istrate ◽  
Nicanor Cimpoeșu ◽  
Mihai-Adrian Bernevig ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Intermetallic Phase ◽  
Young Modulus ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Medical Field ◽  
Pure Zinc ◽  
X Ray ◽  
Knowing That ◽  
Master Alloys

Zinc biodegradable alloys attracted an increased interest in the last few years in the medical field among Mg and Fe-based materials. Knowing that the Mg element has a strengthening influence on Zn alloys, we analyze the effect of the third element, namely, Y with expected results in mechanical properties improvement. Ternary ZnMgY samples were obtained through induction melting in Argon atmosphere from high purity (Zn, Mg, and Y) materials and MgY (70/30 wt%) master alloys with different percentages of Y and keeping the same percentage of Mg (3 wt%). The corrosion resistance and microhardness of ZnMgY alloys were compared with those of pure Zn and ZnMg binary alloy. Materials were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), linear and cyclic potentiometry, and immersion tests. All samples present generalized corrosion after immersion and electro-corrosion experiments in Dulbecco solution. The experimental results show an increase in microhardness and indentation Young Modulus following the addition of Y. The formation of YZn12 intermetallic phase elements with a more noble potential than pure Zinc is established. A correlation is obtained between the appearance of new Y phases and aggressive galvanic corrosion.

Experimental Investigation on Thermal Conduction of Carbon Nanotubes Reinforced Copper Matrix Composites

2014 ◽  
Vol 564 ◽  
pp. 455-460
Author(s):  
Faiz Ahmad ◽  
Muhammad Aslam ◽  
M. Rafi Raza ◽  
Ali S. Muhsan ◽  
M.irfan Shirazi
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Sintered Density ◽  
Pure Copper ◽  
Copper Particle ◽  
Copper Matrix ◽  
Powder Metallurgy Method ◽  
Matrix Composites ◽  
Electron Microscopic ◽  
Scanning Electron

The performance of the micro-chip is affected by overheating and hence reduces the efficiency of electronic devices. The development of high thermal conductivity material can solve problems associated with dissipation of heat from the micro-chips. Thermal conductivity for carbon nanotubes (CNTs) are in the ranges of 1200-3000 W/moK which considered as the best candidate material for heat sink applications. This research investigates the fabrication of CNTs reinforced copper composites using powder metallurgy method. Copper powder and CNTs were ball milled to prepare mixtures and compacted at 600 MPa to fabricate test samples. The compacted test samples were sintered in argon atmosphere at 850oC. Sintered density of CNTs/Cu composites was measured and compared with theoretical density. Density data showed that 98% sintered density was achieved. Optical and scanning electron microscopic (SEM) examination of sintered compacts showed good grain growth, however porosity was also noted in sintered samples. Field emission scanning electron microscopy (FESEM) showed well dispersion of CNTs in copper matrix and interfacial bonding between copper particle and CNTs. In this experiment, the addition of 2 % vol. CNTs in copper matrix showed 9% increase in thermal conductivity approximately compared to thesintered pure copper.

scholarly journals The Dilatometric Analysis of the High Carbon Alloys from Ni-Ta-Al-M System

2014 ◽  
Vol 59 (3) ◽  
pp. 977-980 ◽  
Author(s):  
P. Bała
Keyword(s):  
Elevated Temperatures ◽  
Volume Fraction ◽  
Intermetallic Phase ◽  
Coarse Grained ◽  
Precipitation Process ◽  
Cast State ◽  
High Carbon ◽  
Chromium Carbides ◽  
Tantalum Carbides ◽  
Co Alloys

Abstract In the following work presents results of high carbon alloys from the Ni-Ta-Al-M system are presented. The alloys have been designed to have a good tribological properties at elevated temperatures. Despite availability of numerous hot work tool materials there is still a growing need for new alloys showing unique properties, which could be used under heavy duty conditions, i.e. at high temperatures, in a chemically aggressive environment and under heavy wear conditions. A characteristic, coarse-grained dendritic microstructure occurs in the investigated alloys in the as-cast condition. Primary dendrites with secondary branches can be observed. Tantalum carbides of MC type and graphite precipitations are distributed in interdendritic spaces in the Ni-Ta-Al-C and Ni-Ta-Al-C-Co alloys, while Tantalum carbides of MC type and Chromium carbides of M7C3 type appeared in the Ni-Ta-Al-C-Co-Cr and Ni-Ta-Al-C-Cr alloys. In all alloys g’ phase is present, however, its volume fraction in the Ni-Ta-Al-C and Ni-Ta-Al-C-Co alloys is small.During heating from as-cast state in Ni-Ta-Al-C and Ni-Ta-Al-C-Co alloys, the beginning of the tantalum carbides precipitation process (MC type) followed (or simultaneous) by the intermetallic phase precipitation (g’ – Ni3(AlTa)) was stated, while in Ni-Ta-Al-C-Co-Cr and Ni-Ta-Al-C-Cr alloys, besides Tantalum carbides also the Chromium carbides precipitation occurred. It means that the investigated alloys were partially supersaturated in as-cast state. Above 1050°C in all investigated alloys the g’ phase is dissolving. In addition, the precipitation of secondary carbides during slow cooling was occured.

Thermal Expansion of Polyether Ether Ketone Bearing Components

2019 ◽  
Vol 64 (4) ◽  
pp. 1-5 ◽  
Author(s):  
Bryan D. Allison ◽  
Connor M. Vanderwiel
Keyword(s):  
Thermal Expansion ◽  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Aerospace Applications ◽  
Polyether Ether Ketone ◽  
Molded Parts ◽  
Injection Molded ◽  
Ether Ketone ◽  
Bearing Design ◽  
Strong Candidate

Carbon fiber–reinforced polyether ether ketone (PEEK) is a strong candidate for aerospace bearing cages due to its low density and good mechanical properties. However, there are still concerns regarding its performance at the elevated temperatures seen in aerospace applications. In particular, an accurate measurement of PEEK's coefficient of thermal expansion (CTE) is critical to proper bearing design. In this paper, the CTE of as-manufactured PEEK cages was measured to determine the range of CTE that can be expected for production parts. A range of cage sizes and designs were considered in this study. Components that were manufactured from stock shapes through subtractive methods were studied in addition to components made via injection molding. The CTE of machined PEEK was found to be significantly higher than that of injection-molded PEEK and also varied significantly from part to part. In contrast, the CTE of molded PEEK cages was found to be fairly consistent between parts. Finally, the CTE of PEEK was found to increase above the glass transition temperature of 143 °C, but it was demonstrated that this increase is relatively small for injection-molded parts.

Microstructure and Properties of Co@RGO/Cu Composites by One-Step In Situ Reduction Method

2020 ◽  
Vol 993 ◽  
pp. 646-653
Author(s):  
Shao Hui Liu ◽  
Yu Zhao ◽  
Xu Ran
Keyword(s):  
Composite Material ◽  
Graphene Oxide ◽  
Reduction Method ◽  
Pure Copper ◽  
Copper Matrix ◽  
Comprehensive Properties ◽  
Plasma Sintering ◽  
Reduced Graphene ◽  
One Step

In order to improve the interfacial bonding between graphene and copper and improve the dispersibility of graphene in the copper matrix, a novel method was used to prepare graphene. Firstly, graphene oxide (GO) was prepared by the modified Hummer's method, and then the reduced graphene oxide-supported cobalt nanoparticle composite powder (Co@RGO) was prepared by one-step in-situ reduction method. The fabricated materials were mixed with copper powder to obtain various volume fractions. The powder mixture was subjected to compression and discharge plasma sintering (SPS) to prepare a bulk copper-based composite material. The microstructure and its comprehensive properties were studied by SEM, TEM, XRD, FTIR and Raman. The results show that the agglomeration of graphene can be effectively inhibited after the cobalt nanoparticles supported on the graphene surface. The proper amount of Co@RGO could be uniformly dispersed in the copper matrix. The composite material showed a high electrical conductivity (>86% IACS), and the Vickers hardness also increased by about 30% compared with pure copper.

Ultrasonic Inspection of Carbon/ Phenolic Composites Using a Peak-Delay Measurement Method

2006 ◽  
Vol 321-323 ◽  
pp. 889-892
Author(s):  
In Young Yang ◽  
Kwang Hee Im ◽  
David K. Hsu ◽  
Sung Jin Song ◽  
Hyeon Cho ◽  
...  
Keyword(s):  
Ultrasonic Velocity ◽  
Measurement Method ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Ultrasonic Inspection ◽  
Carbon Matrix ◽  
Transmission Method ◽  
Aerospace Applications ◽  
Delay Measurement ◽  
Overlap Method

Carbon/phenolic composite (CPC) materials are unique which consist of carbon fibers embedded in a carbon matrix. The CPCs are originally developed for aerospace applications and its low density, high thermal conductivity and excellent mechanical properties at elevated temperatures make it an ideal material for aircraft brake disks. The properties of the CPC are dependent on the manufacturing methods used for production and fiber arrangement. It is desirable to perform nondestructive evaluation to assess material properties and part homogeneity in order to ensure product quality and structural integrity of CPC brake disks. In this work, a CPC material was nondestructively characterized and a technique was developed to measure ultrasonic velocity in C/P composites using automated data acquisition software. Also a motorized system was adopted to measure ultrasonic velocity on the point of CPC materials under the same coupling conditions. Manual results were compared with those obtained by the motorized system with using drycoupling ultrasonics and through transmission method in immersion. A peak-delay measurement method well corresponded to ultrasonic velocities of the pulse overlap method and throughtransmission mode and C-scan image signal based on peak-to-peak amplitude.

Characterization of Mechanical Properties of Carbon Nanotubes in Copper-Matrix Nanocomposites

2006 ◽  
Author(s):  
Seunghyun Baik ◽  
Byeongsoo Lim ◽  
Bumjoon Kim ◽  
Untae Sim ◽  
Seyoung Oh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Pure Copper ◽  
Copper Matrix ◽  
Mixing Process ◽  
Mechanical Mixing ◽  
Matrix Nanocomposites ◽  
Coated Carbon

Carbon nanotubes have received considerable attention because of their excellent mechanical properties. In this study, carbon nanotube - copper composites have been sintered by a mechanical mixing process. The interfacial bonding between nanotubes and the copper matrix was improved by coating nanotubes with nickel. Sintered pure copper samples were used as control materials. The displacement rate of nanotube-copper composites was found to increase at 200°C whereas that of nickel-coated nanotue-copper composites significantly decreased. The incorporation of carbon nanotubes and nickel-coated carbon nanotubes in the copper matrix decreased friction coefficients and increased the time up to the onset of scuffing compared with those of pure copper specimens.

An Investigation on Anti-Corrosion Properties of Electroplated Copper-Graphene Nano-Composite Films

2020 ◽  
Vol 978 ◽  
pp. 499-504 ◽  
Author(s):  
Akhya Kumar Behera ◽  
Archana Mallik
Keyword(s):  
Thin Films ◽  
Corrosion Rate ◽  
Pure Copper ◽  
Copper Matrix ◽  
Reinforcement Particle ◽  
Graphene Sheets ◽  
Borate Buffer Solution ◽  
Buffer Solution ◽  
Corrosion Properties ◽  
Electroplated Copper

In this report, graphene sheets used as reinforcements for improvement of anti-corrosion properties have been synthesized by electrochemical intercalation and exfoliation process. The (001) and (002) plane of graphene sheets at a 2θ angle of 13.2 and 26.13 confirmed by X-ray diffraction pattern. High-resolution TEM confirms 8-12 layers of graphene present in the final products. The as-received graphene sheets have been used as reinforcement with copper matrix to synthesize Cu-Gr nanocomposite by electrodeposition method. The results and investigations of Cu-Gr composite thin films deposited from the bath containing 0.1g/L and 0.5g/L graphene concentrations with acidic copper sulfate solution have been compared. The surface morphology and roughness of composites were studied by SEM, AFM and surface profiler. The presence of graphene in Cu-Gr nanocomposite confirmed by EDS analysis. It was observed that the reinforcement particle has increased the mechanical properties of Cu-Gr composite (by 30%) with the addition to the copper matrix. The corrosion resistance of sample was studied by Tafel extrapolation method in standard borate buffer solution. For nanocomposites of 0.5g/L graphene, the values of Tafel constants are, βa=177.37 mv, βc=138.51 mv, Icorr = 9.3165×10-7Amp/cm2, Ecorr = -0.051 volts and corrosion rate 0.01028 mm/a as comparison to the corrosion rate of pure electroplated copper of a value of 0.029 mm/a. The corrosion rate of 0.5g/L Cu-Gr composite was found to be decreased by 2.7 times as compared to pure copper thin films. The structure of the films before and after corrosion was also analyzed to co-relate the electrochemical and structural relationship.

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