Severe Plastic Deformation of a Commercial Aluminium-Lithium Alloy (AA8090) by Equal Channel Angular Pressing

2006 ◽  
Vol 503-504 ◽  
pp. 871-876 ◽  
Author(s):  
Núria Llorca-Isern ◽  
P.A. Gonzalez ◽  
C.J. Luis-Pérez ◽  
I. Laborde
Keyword(s):  
Mechanical Properties ◽  
Research Work ◽  
Tensile Tests ◽  
Lithium Alloy ◽  
Angular Pressing ◽  
Processed Material ◽  
The Matrix ◽  
Potential Mode ◽  
Commercial Aluminium ◽  
Nano Grains

The enhanced mechanical properties of crystalline materials are linked to very small grain sizes. The AA8090 is a commercial aluminium lithium alloy is referred in the metallurgical literature by its superplastic behavior linked as well to nano-grains as obtained by ECAP. On this research-work in progress, the 8090 aluminium alloy is studied after being processed in a 400 kN ECAE press up to nine passes through a 90º angle-die at 150 °C following Route A (constant path) at a processing speed of 10 mm/min. The room temperature mechanical properties of the extruded alloy are investigated through hardness measurements and tensile tests. Elastic measurements have been carried out by means of nanoindentation and ultrasonic testing, showing that both texture and nanostructuration of the processed alloy influence on the elastic constant of the processed material. In order to understand the mechanisms involved in the SPD-ECAP process, microstructural characterisation of the alloy has been carried out using different high resolution techniques such as Transmission Electron and Atomic Force Microscopy. TEM results have also been used in order to evaluate grain size evolution. From this analysis it is possible to see that after 4 passages the initial grains have already a high degree of dislocations. Among the characterisation techniques, AFM in the surface potential mode has been used to evaluate discontinuities in the matrix and /or decohesion between matrix and precipitates. After nine ECAP passages, no signs of decohesion at the interface have been observed neither using FEG-SEM nor using AFM.

Fracture Analysis and Mechanical Properties of Magnesium Based Composites

2017 ◽  
Vol 891 ◽  
pp. 526-532 ◽  
Author(s):  
Beáta Ballóková ◽  
Dagmar Jakubéczyová
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Fracture Analysis ◽  
Physical Parameters ◽  
Weight Percentage ◽  
Matrix Microstructure ◽  
Angular Pressing ◽  
The Matrix ◽  
Average Size

Mechanical properties and microstructure and fracture analysis of a magnesium alloys based composite series with different volume fraction of alumina dispersoid nanoparticles were studied. The initial states of the composites were further treated by severe plastic deformation (SPD) using equal channel angular pressing (ECAP) in order to achieve microstructures with very fine grains of matrix. Microstructure parameters, in particular the matrix grain size, average size of the dispersed particles and their distribution, were observed using optical microscopy. The average grain sizes of MMCs decreased evidently with the increase of the weight percentage of Al2O3 particles additions and ECAP passes. The heat deformation process of such materials, besides the formation of incorporated Al2O3 particles, also leads to the creation of intermetallic compound Mg17Al12. Fracture surfaces after tensile tests at room and elevated temperature were studied by SEM. The fracture of studying materials were characterized as the ductile fracture due to the existence of a large number of dimples.In summary, it has been shown that mechanical properties are affected by lattice, physical parameters of phases within the composite systems. They are also affected by microstructure and substructure, which depend on the technology of compaction and densification.

scholarly journals Tensile Behavior of a Glass FRCM System after Different Environmental Exposures

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1074
Author(s):  
Jacopo Donnini ◽  
Francesca Bompadre ◽  
Valeria Corinaldesi
Keyword(s):  
Mechanical Properties ◽  
Environmental Exposures ◽  
Tensile Tests ◽  
Chromatography Analysis ◽  
The Matrix ◽  
Externally Bonded ◽  
Open Issue ◽  
Flexural Tests ◽  
Fabric Reinforced Cementitious Matrix ◽  
Inorganic Matrix

The use of Fabric-Reinforced Cementitious Matrix (FRCM) systems as externally bonded reinforcement for concrete or masonry structures is, nowadays, a common practice in civil engineering. However, FRCM durability against aggressive environmental conditions is still an open issue. In this paper, the mechanical behavior of a glass FRCM system, after being subjected to saline, alkaline and freeze–thaw cycles, has been investigated. The experimental campaign includes tensile tests on the fabric yarns, compression and flexural tests on the matrix and tensile tests (according to AC434) on FRCM prismatic coupons. The effects of the different environmental exposures on the mechanical properties of both the constituent materials and the composite system have been investigated and discussed. Ion chromatography analysis has also been performed to better understand the damage mechanisms induced by environmental exposures and to evaluate the ions’ penetration within the inorganic matrix. Alkaline exposure was shown to be the most detrimental for Alkali-Resistant (AR) glass fiber yarns, causing a reduction in tensile strength of about 25%. However, mechanical properties of the FRCM composite seemed not to be particularly affected by any of the artificial aging environments.

Behaviour of Vacuum Casting Plastic Composites Under Different Treatments of Banana Fibres

2010 ◽  
Author(s):  
M. D. Monzo´n ◽  
Z. Ortega ◽  
A. N. Beni´tez ◽  
P. M. Herna´ndez ◽  
M. D. Marrero ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Research Work ◽  
Natural Fibers ◽  
Vacuum Casting ◽  
The Sustainable Development ◽  
The Matrix ◽  
Efficiency Factors ◽  
And Behavior ◽  
Fibre Matrix

Nowadays, the natural fibres market is having an important growth due to the commitment of contemporary society with the sustainable development that leads the natural resources preservation and the environment protection. Fibres from banana food wastes provide high mechanical properties related to other natural fibers such as flax, sisal, hemp, etc. The aim of the present research work is to compare different banana fibres processing in order to improve the matrix fibre adhesion and behavior of fibre under processing conditions. Simple Anova analysis has been implemented on four different formulations: 1. No fibre processing, 2. Alkaline processing with Caustic Soda (NaOH), 3 Maleic Anhydride, 4. Combination of Soda and Maleic Anhydride. Several samples of MTT 8040 resin, under vacuum casting, with silicone moulds, conditions, have been done. Mechanical properties and efficiency factors of adhesion fibre-matrix have been determined and compared.

In Situ TiB2 and Al2(Y, Gd) Particles Reinforced Magnesium Matrix Composite with Al-Ti-B Addition

2013 ◽  
Vol 312 ◽  
pp. 315-318 ◽  
Author(s):  
C.F. Fang ◽  
L.G. Meng ◽  
N.N. Wu ◽  
X.G. Zhang
Keyword(s):  
Mechanical Properties ◽  
Matrix Composite ◽  
Matrix Alloy ◽  
Tensile Tests ◽  
Solidification Structure ◽  
Magnesium Matrix Composite ◽  
Magnesium Matrix ◽  
Reinforced Composite ◽  
The Matrix

In-situ micro/nanosized TiB2 and Al2(Y, Gd) particles reinforced magnesium matrix composite was successfully fabricated by addition of Al-Ti-B preform into Mg-Gd-Y-Zn matrix alloy, its microstructures and properties were investigated. The results show that the introduction of Al-Ti-B preform causes the precipitation of Al2(Y, Gd) particles and the SHS synthesis of TiB2 particles which significantly refine solidification structure. The reinforced Al2(Y, Gd) particles with average sizes of 5-8 μm are uniformly distributed throughout the magnesium matrix, and have a good bond to the matrix. Tensile tests indicate that, compared with the former matrix alloy, mechanical properties of the multiple in-situ particles reinforced composite are improved all-roundly.

Preparation of MWCNT/Carbon Fabric Reinforced Hybrid Nanocomposite and Examination of its Mechanical Properties

2008 ◽  
Vol 589 ◽  
pp. 269-274 ◽  
Author(s):  
Gábor Romhány ◽  
Gábor Szebényi
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Carbon Fiber ◽  
Hybrid Composite ◽  
Tensile Tests ◽  
Hybrid Nanocomposite ◽  
Shear Rates ◽  
The Matrix ◽  
Interlaminar Shear ◽  
Carbon Fiber Epoxy

In our work we have prepared carbon fiber/epoxy composite and carbon fiber/carbon nanotube/epoxy hybrid nanocomposite laminates by hand laminating assisted by vacuumbag technology. During the production of the specimens we have encountered the viscosity increasing effect of nanotube filling, which we characterized by a viscosity test. The results of the test showed, that in the lowest shear rate range carbon nanotube filling can cause an increase of viscosity by three orders of magnitude, but also at higher shear rates the viscosity of the nanotube filled epoxy resin was ten times the viscosity of the unfilled resin. Mechanical properties of the composite and hybrid composite have been compared by tensile, bending and interlaminar shear tests. During the tensile tests AE signals have also been recorded. The fracture surfaces have been examined by SEM micrographs. The nanotube filling has decreased the tensile strength and the modulus of elasticity by 7-8 percent presumably indirectly, the bending properties didn’t change noticeably, but the interlaminar shear strength of the composite has increased by 15 percent thanks to nanotube filling of the matrix. The decrease of the delamination inclination of the hybrid composite has been affirmed both by the AE and SEM results.

Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites

2006 ◽  
Vol 980 ◽  
Author(s):  
Hongbin Bei ◽  
E. P. George
Keyword(s):  
Mechanical Properties ◽  
Cast Alloy ◽  
Tensile Tests ◽  
Eutectic Structure ◽  
Directionally Solidified ◽  
Quaternary Alloys ◽  
The Matrix ◽  
Solid Solution Matrix ◽  
Solution Matrix

AbstractFe-Co-V-C quaternary alloys were drop cast and directionally solidified to obtain an in situ composite. It is found that the fully eutectic structure occurs at a composition of Fe - 40.5Co -10.4V- 8.6C (at. %) in a drop-cast alloy. Directional solidification of this composition in a high-temperature optical floating zone furnace produces a well-aligned microstructure, consisting of sub-micron VC fibers (~19% by volume) embedded in a FeCo-5V solid solution matrix containing ~ 1% C. The temperature dependencies of mechanical properties of this composite were examined by tensile tests and the composite was found to have higher yield strength and lower ductility than the matrix.

Analysis and Numerical Simulation of the Mechanical Performance of FDM Samples With Variable Infill Values

2017 ◽  
Author(s):  
Steffany N. Cerda-Avila ◽  
Hugo I. Medellín-Castillo ◽  
Dirk F. de Lange
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Prediction Models ◽  
Mechanical Performance ◽  
Numerical Models ◽  
Research Work ◽  
Tensile Tests ◽  
Geometrical Shape ◽  
Cad System ◽  
Fem Method

The prediction of the mechanical properties of AM parts is very important in order to design and fabricate parts not only of any geometrical shape but also with variable or customized mechanical properties. A limited number of investigations have focused on the analysis and prediction of the mechanical properties of AM parts using theoretical and numerical approaches such as the Finite Element Method (FEM); nevertheless, their results have been not accurate yet. Thus, more research work is needed in order to develop reliable prediction models able to estimate the mechanical performance of AM parts before fabrication. In this paper the analysis and numerical simulation of the mechanical performance of FDM samples with variable infill values is presented. The aim is to predict the mechanical performance of FDM components using numerical models. Thus, several standard tensile test specimens were fabricated in an FDM system using different infill values, a constant layer thickness, one shell perimeter, and PLA material. These samples were measured and modelled in a CAD system before performing the experimental tensile tests. Numerical models and simulations based on the FEM method were then developed and carried out in order to predict the structural performance of the specimens. Finally the experimental and numerical results were compared and conclusions drawn.

scholarly journals The Effect of Equal-Channel Angular Pressing on Microstructure, Mechanical Properties, and Biodegradation Behavior of Magnesium Alloyed with Silver and Gadolinium

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 918
Author(s):  
Boris Straumal ◽  
Natalia Martynenko ◽  
Diana Temralieva ◽  
Vladimir Serebryany ◽  
Natalia Tabachkova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Fine Particles ◽  
Volume Fraction ◽  
Galvanic Corrosion ◽  
Angular Pressing ◽  
Average Grain Size ◽  
The Matrix ◽  
Mechanical Properties And Corrosion

The effect of equal channel angular pressing (ECAP) on the microstructure, texture, mechanical properties, and corrosion resistance of the alloys Mg-6.0%Ag and Mg-10.0%Gd was studied. It was shown that ECAP leads to grain refinement of the alloys down to the average grain size of 2–3 μm and 1–2 μm, respectively. In addition, in both alloys the precipitation of fine particles of phases Mg54Ag17 and Mg5Gd with sizes of ~500–600 and ~400–500 nm and a volume fraction of ~9% and ~8.6%, respectively, was observed. In the case of the alloy Mg-6.0%Ag, despite a significant grain refinement, a drop in the strength characteristics and a nearly twofold increase in ductility (up to ~30%) was found. This behavior is associated with the formation of a sharp inclined basal texture. For alloy Mg-10.0%Gd, both ductility and strength were enhanced, which can be associated with the combined effect of significant grain refinement and an increased probability of prismatic and basal glide. ECAP was also shown to cause a substantial rise of the biodegradation rate of both alloys and an increase in pitting corrosion. The latter effect is attributed to an increase in the dislocation density induced by ECAP and the occurrence of micro-galvanic corrosion at the matrix/particle interfaces.

Microstructure Evolution of Pure Nickel up to a High Strain Level during Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 319-324 ◽  
Author(s):  
Fan Liu ◽  
Yue Zhang ◽  
Jing Tao Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Tensile Tests ◽  
Dislocation Cell ◽  
Pure Nickel ◽  
Strain Level ◽  
Strength Increase ◽  
Angular Pressing ◽  
Cell Structures

Nickel of 99.5% purity, with an initial grain size of ~23 μm, was subjected to equal-channel angular pressing (ECAP) up to a strain of ~12 at room temperature via route Bc. Mechanical properties and microstructures are investigated by tensile tests, microhardness tests, TEM, and EBSD observations. Results of mechanical properties show that yield strength and tensile strength increase as strain increase up to a max value( s~1009 MPa, b~1120 MPa) at ~8, and microhardness reaches its maximum of ~370HV after 12 passes. Analysis by TEM showed that grain size of pure nickel was severely refined from ~23 μm to several hundreds of nanometers after ECAP processing. Initial coarse grain are divided with lamellar boundaries and dislocation cell structures at low strain level, there has resulted in a homogenous and fine spacing of lamellar boundaries (~100 nm) after 4 passes of ECAP, low angle characters of those boundaries are revealed from corresponding SAED pattern; equiaxed grains of diameter with ~98 nm come out among lamellar boundaries after 12 passes.

The Effect of Plastic Consolidation Parameters on the Microstructure and Mechanical Properties of Various Aluminium Powders

2011 ◽  
Vol 674 ◽  
pp. 141-146 ◽  
Author(s):  
Tomasz Tokarski
Keyword(s):  
Mechanical Properties ◽  
Research Work ◽  
Hot Extrusion ◽  
Tensile Tests ◽  
Material Strength ◽  
Cast Aluminum ◽  
Consolidation Process ◽  
Additional Material ◽  
Cast Material ◽  
Aluminum Powders

The present paper is aimed at investigations of mechanical properties and structure of technical purity aluminum powders prepared by plastic consolidation process. The research work is focused on effective improvement of mechanical properties of material while keeping the conductivity at high level. It is well known that application of rapid solidification method with hot extrusion technique leads to grain refinement, as so according to Hall-Petch rule, improvement in mechanical properties of material can be expected. Furthermore, additional material strength can be obtained by aluminum oxides from free surface of powders that became internal boundaries during consolidation process. Aluminum powders atomized by air, argon and water were cold compacted and extruded at temperatures of 325°C and 375°C. For comparison purposes the same extrusion conditions were applied to cast aluminum. In order to analyze effect of recrystalization process during hot extrusion operation, different extrusion temperatures were chosen. Tensile tests as well as micro-hardnes measurements showed significant increase in mechanical strength for RS samples in comparison to conventionally cast material. Structural observations by means of transmission electron microscopy revealed that grain size of materials extruded at the given temperature was at the same level, however amount and distribution of oxides particles differs significantly. It was considered that differences in strength between individual RS material were attributed to this effect.

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