Showing 25 results for Casting
M. Ghalambaz, M. Shahmiri,
Volume 5, Issue 3 (9-2008)
Abstract
Abstract: Cooling slope-casting processing is a relatively new technique to produce semisolid cast
feedstock for the thixoforming process. Simple equipment, ease of operation, and low processing
costs are the main advantages of this process in comparison with existing processes such as
mechanical stirring, electromagnetic stirring, etc. The processing parameters of cooling slope
casting are length, angle and the material of the inclined plate and their combinations, which
usually affect the micro structural evolutions of the primary solid phase.
In order to clarify the effect of the processing parameters on the evolution of the particle size,
based on experimental investigation, Artificial Neural Network (ANN) was applied to predict the
primary silicon crystals (PSCs) size of semisolid cast ingot via a cooling slope casting process of
Al-20%(wt.%) Si alloy.
The results demonstrated that the ANN, with 2 hidden layers and topology (4, 3), could predict the
primary particle size with a high accuracy of 94%. The sensitivity analysis also revealed that
material of the cooling slope had the largest effect on particle size.
S. Kianfar,, S. H. Seyedein, M. R.aboutalebi,
Volume 5, Issue 4 (12-2008)
Abstract
Abstract: The horizontal continuous casting process has received a significant attention for near net shape casting of
non ferrous metals and alloys. Numerical Simulation has been widely used for process design and optimization of
continuous casting process.
In the present study, a 3-dimensional heat flow model was developed to simulate the heat transfer and solidification in
a horizontal billet continuous casting system in which the air gap formation and its effect on heat extraction rate from
solidifying billet was also considered. In order to test the developed model, it was run to simulate the heat transfer
and solidification for an industrial billet caster. The predicted temperature distribution within the mold and billet was
compared with those measured on the industrial caster in which a good agreement was obtained.
Finally, parametric studies were carried out by validated model to evaluate the effects of different parameters on
solidification profile and temperature distribution within the model brass billet. The microstructure of cast billet was
analyzed to determine the secondary dendrite arm spacing (SDAS) under different cooling conditions. Based on
measured SDAS and predicted solidification rate a correlation between SDAS and cooling rate was proposed for
continuously cast brass billet.
A. H. Shafie Farhood, F. Akhlaghi,
Volume 7, Issue 1 (3-2010)
Abstract
Abstract:
structures in alloys. This method is based on pouring the melt through a small sized nozzle into a mould located at a
certain height under the crucible. This simple method generates globular structures without using equipments such as
impellers, electromagnetic stirrers, ultrasonic probes and cooling slopes. Therefore it is cost effective. In the present
study, the effect of casting size and mould casting modulus on the globular structure evolution in A356 aluminium alloy
specimens prepared by NMS process was investigated. The results showed that regardless of the different casting
modulus and their sizes, all the specimens exhibited globular structures. However, the size and shape factor of the
globules decreased with increased casting modulus and casting size indicating the influential effect of the surface area
of the mould in generating globular structures in this process.
Narrow Melt Stream (NMS) is a relatively new semisolid metal processing technique for producing globular
A. Jafaria, S. H. Seyedeina, M. R. Aboutalebia, D. G. Eskinb, L. Katgermanb,
Volume 7, Issue 3 (8-2010)
Abstract
ABSTRACT Macrosegregation has been received high attention in the solidification modeling studies. In the present work, a numerical model was developed to predict the macrosegregation during the DC Casting of an Al-4.5wt%Cu billet. The mathematical model developed in this study consists of mass, momentum, energy and species conservation equations for a two-phase mixture of liquid and solid in an axisymmetric coordinates. The solution methodology is based on a standard Finite Volume Method. A new scheme called Semi-Implicit Method for Thermodynamically-Linked Equations (SIMTLE) was employed to link energy and species equations with phase diagram of the alloying system. The model was tested by experimental data extracted from an industrial scale DC caster and a relatively good agreement was obtained. It was concluded that a proper macrosegregation model needs two key features: a precise flow description in the two-phase regions and a capable efficient numerical scheme
W. Orlowicz, M. Tupaj, M. Mróz, J. Betlej, F. Ploszaj,
Volume 9, Issue 1 (3-2012)
Abstract
Abstract: This study presents the research results of effect that refining process has on porosity and mechanical properties of high pressure die castings made of AlSi12S alloy. The operation of refining was carried out in a melting furnace with the use of an FDU Mini Degasser. Mechanical properties (UTS, YS, Elongation, Brinell Hardness) were assessed on samples taken from high pressure die castings. The effect of molten metal transfer operation and the time elapsing from completion of the refining process on the alloy mechanical properties was determined.
M. Alipour, S. Mirjavadi, M. K. Besharati Givi, H. Razmi, M. Emamy, J. Rassizadehghani,
Volume 9, Issue 4 (12-2012)
Abstract
In this study the effect of Al–5Ti–1B grain refiner on the structural characteristics and wear properties of Al–12Zn–3Mg–2.5Cu alloy was investigated. The optimum amount for Ti containing grain refiners was selected as 2 wt.%. T6 heat treatment, (i.e. heating at 460 °C for 1 h before water quenching to room temperature and then aging at 120 °C for 24 h) was applied for all specimens before wear testing. Dry sliding wear resistant of the alloy was performed under normal atmospheric conditions. The experimental results showed that the T6 heat treatment considerably improved the resistance of Al–12Zn–3Mg–2.5Cu alloy to dry sliding wear.
N. Najmoddin, H.r. Rezaie, A. Beitollahi, M.s. Toprak,
Volume 11, Issue 3 (9-2014)
Abstract
The synthesis of mesoporous CuFe2O4 spinel by several nanocasting strategies (i.e., multi-step nanocasting, one step nanocasting, modified solid-liquid), in which copper and iron nitrates are used as precursors and Pluronic P123 as surfactant, is explored. We have also checked the effect of pH, citric acid and sodium citrate in multi-step nanocasting method. The modified solid-liquid method which contains impregnating mesoporous silica by molten state salts in a non-ionic solvent seems to be the best choice to obtain single phase ordered mesoporous copper ferrite. Other methods suffer from the presence of copper oxide or hematite as impurities or lack of integrity in the mesoporous structure. Increasing pH up to 9.5 does not enhance the phase formation inside the pores of the silica matrix. The citric acid yields a fine structure but does not facilitate the phase formation. Adding sodium citrate neither heals the phase formation nor the structure of the final product. Moreover, vinyl- functionalized mesoporous silica exploited in this study as a hard template entraps both metal nitrates in the pores, assisting impregnation procedure
A. Fattah-Alhosseini, M. Ranjbaran, S. Vajdi Vahid,
Volume 12, Issue 2 (6-2015)
Abstract
In this study, corrosion behaviour of A356-10 vol.% SiC composites casted by gravity and squeeze casting
is evaluated. For this purpose, prepared samples were immersed in HCl solution for 1h at open circuit potential. Tafel
polarization and electrochemical impedance spectroscopy (EIS) were carried out to study the corrosion resistance of
composites. The Tafel polarization and EIS studies of the corrosion behaviour of the A356-10 vol.% SiC composites
showed that the corrosion resistance of the composite casted by squeeze casting was higher than that of the composites
casted by gravity in selected corrosion media. Also, the Tafel polarization and EIS studies revealed that the corrosion
current densities of both composites increase with the increase in the concentration of HCl. The micrographs of
scanning electron microscope (SEM) clearly showed the squeeze casting composite exhibits a good dispersion/matrix
interface compared to that of the composites produced by gravity casting
M. Alipour, M. Emami, R. Eslami Farsania, M. H. Siadati, H. Khorsand,
Volume 12, Issue 4 (12-2015)
Abstract
A modified strain-induced melt activation (SIMA) process was applied and its effect on the structural characteristics and hardness of the aluminum alloy Al–12Zn–3Mg–2.5Cu was investigated. Specimens subjected to a deformation of 40% at 300 °C were heat treated at various times (10-40 min) and temperatures (550-600 °C). Microstructural studies were carried out using optical and scanning electron microscopies (SEM). Results showed that the best microstructure was obtained at the temperature and time of 575 °C and 20 min, respectively. The hardness test results revealed superior hardness in comparison with the samples prepared without the application of the modified SIMA process.
T6 heat treatment including quenching to 25 °C and aging at 120 °C for 24 h was employed to reach to the maximum strength. After the T6 heat treatment, the average tensile strength increased from 231 MPa to 487 and 215 MPa to 462 for samples before and after strain-induced melt activation process, respectively. Ultimate strength of globular microstructure specimens after SIMA process has a lower value than as-cast specimens without SIMA process
N. Maragani, K. Vijaya Kumar,
Volume 15, Issue 4 (12-2018)
Abstract
An attempt has been focused to develop a new aluminum ion conducting non aqueous polymer electrolyte for high power rechargeable batteries having applications in rapidly growing markets, such as laptops, handy tele communication equipments, electric vehicles, camcorders, etc. These features have given a thrust to develop a suitable Nano composite GPE based on PAN as polymer host and Sodium fluoride (NaF) as dopant salt and Al2O3 as nano filler in the form of thin films through solution casting technique consuming N,N-dimethyl formamide (DMF) as a common solvent. NCGPE films have been prepared by solution casting technique. The XRD pattern of 70PAN-30NaF with addition of wt% Al2O3 ceramic filler indicates reducing degree of crystallinity. Using IR studies revealed that the complexation of the polymer poly (acrylonitrle) with NaF. The conductivity of the GPEs was studied with enhancement of nano fillers. The sample containing 3% of Al2O3 exhibits the highest conductivity of 4.82x10-3S cm-1 at room temperature (303K) and 5.96x10-3S cm-1 at 378K. With the help of Wagner’s polarization technique electronic (te) and ionic (ti) values can be determined.To determine profiles of discharge characteristics (70PAN-30NaF-3wt% Al2O3) NCGPE solid-state electrochemical cell was fabricated and various cell profiles were evaluated
S. Kord, M. H. Siadati, M. Alipour, H. Amiri, P.g. Koppad, A. C. Gowda,
Volume 15, Issue 4 (12-2018)
Abstract
The effects of rare earth element, erbium (Er) additions on the microstructure and mechanical properties of Al-15Zn-2.5Mg-2.5Cu alloy have been investigated. This new high strength alloy with erbium additions (0.5, 1.0, 1.5 and 2.0 wt%) was synthesized by liquid metallurgy route followed by hot extrusion. Microstructural characterization was performed using scanning electron microscope and electron probe microanalysis. Significant amount of grain refinement was observed with erbium addition in the hot extruded and heat treated alloy. Tensile test was performed to investigate the effect rare earth on mechanical behavior of alloy in as cast and hot extruded condition before and after T6 heat treatment. The combined effect of erbium addition, hot extrusion and heat treatment significantly enhanced the tensile strength of alloy (602 MPa) when compared to the as cast alloy without erbium addition (225 MPa). The strengthening of the alloy was attributed to grain refinement caused by erbium along with hot extrusion and formation of precipitates after T6 heat treatment. Fractograhic investigations revealed that the hot extruded alloy with erbium addition after heat treatment showed uniformly distributed deep dimples exhibiting ductile behavior.
M. Gholami, M. Divandari,
Volume 15, Issue 4 (12-2018)
Abstract
Centrifugal casting process, in both horizontal and vertical mode, is considered as an efficient method to produce bimetallic components. Al/Cu65Zn35 couples were prepared by the vertical centrifugal casting process. In this study, different volume of molten aluminum having melt-to-solid (m/s) volume ratios (VR) of 1.5 and 2.5, were cast into preheated brass bush rotating at 800, 1600, and 2000 (rpm), respectively. The thickness of the interface, which is composed of three different zones, is depended on the rotational speed and the (VR) and was at least 490µm (at VR=1.5 and 2000 rpm) and at most 1480 µm (at VR=2.5 and 800 rpm). The results of optical microscopy, energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction analysis showed that the interface layers are composed of Al2Cu5Zn4, Al3Cu3Zn, Al2Cu precipitates dispersed in the matrix and finally α-Al/Al2Cu anomalous eutectic structure near the aluminum side. Gas pore entrapment and oxide film entrainment defect was detected within the interface next to the aluminum base metal.
M. Tavakoli Harandi, M. Askari-Paykani, H. Shahverdi, M. Nili Ahmadabadi,
Volume 16, Issue 1 (3-2019)
Abstract
One-step and two-step annealing techniques were used to examine the relationship between microstructure and mechanical properties during compression tests in iron-based ribbons and nanostructured 1- and 2.5mm cylindrical rods. The X-ray diffraction, microstructural, and mechanical results showed that substituting Nb for Fe had a minor effect on glass-forming ability but increased the formability index. The novel two-step annealing process resulted in a remarkable formability index of 16.62 GPa, yield stress of 2830 MPa, ultimate strength of 3866 MPa, and 4.3% plastic strain. A ductile nanosized α-Fe framework and boron-containing nano precipitations, which caused Zener pinning effect, were responsible for these novel mechanical properties.
M. Senthil Kumar , R. V. Managalaraja, K. Senthil Kumar, L. Natrayan,
Volume 16, Issue 2 (6-2019)
Abstract
The present requirement of automobile industry is seeking lightweight material that satisfices the technical and technological requirements with better mechanical and tribological characteristics. Aluminium matrix composite ( AMC ) materials meet the requirements of the modern demands. AMCs are used in automotive applications as engine cylinders, pistons, disc and drum brakes. This paper investigates the effect of particle size and wt% of Al2O3/SiC reinforcement on mechanical and tribological properties of hybrid metal matrix composites (HMMCs). AA2024 aluminium alloy is reinforced with Al2O3/SiC different particle sizes (10, 20 and 40 µm) and weight fractions (upto 10 wt %) were fabricated by using squeeze casting technique. HMMCs were characterized for its properties such asX-ray diffraction (XRD), density, scanning electron microscope ( SEM ), hardness, tensile strength, wear and coefficient of friction. AA2024/5wt%Al2O3/5wt%SiC with 10 μm reinforced particle size showed maximum hardness and tensile strength 156.4 HV and 531.43 MPa and decrease in wear rate was observed from from 0.00307 to 0.00221 for 10N. Hybrid composites showed improved mechanical and wear resistance suitable for engine cylinder liner applications.
I. Kakaravada, A. Mahamani, V. Pandurangadu,
Volume 17, Issue 1 (3-2020)
Abstract
In the present investigation, A356-TiB2/TiC composites with a various weight fractions (0, 2.5, 5 and 7.5%) were synthesized through a K2TiF6-KBF4-Graphite (C) reaction system. Formation of TiB2 and TiC particulates and their distribution are confirmed by various characterization techniques. The tensile properties such as ultimate strength, yield strength, young's modulus and percentage of elongation in addition to their failure behavior of these composites were studied at ambiance and high temperatures (100, 200 and 3000C). The increment in the volume fraction of the composite raises the hardness and the enhancement of hardness was reported up to 49% at 7.5% reinforced composite due to the strengthening effect. The density and porosity of fabricated composites were investigated. The rise in volume fraction of reinforcement phase declines the density and increase the porosity of composites. Further, the ultimate strength, yield strength, young's modulus is declining by raising the temperature. Result analysis illustrates that the 7.5% reinforced composite retaining the ultimate strength up to 84.4% and the ductility is raised by 27% at 3000C. Yield strength and young's modulus are also retained 74.31% and 71.09% respectively at the similar material and experimental conditions. The fracture surface analysis of the composites illustrates that, the ductile nature of failure appearance microscopically with the formation of fine dimples and voids on fracture surface at elevated temperatures. Cleavage facets and tear crumples observation indicates the brittle kind of failure at the ambient temperature. Findings from the experimental study provide the tensile behavior of the composites at the regular working temperature of the automobile engine piston.
Tamilanban Thangaraju, Thirupandiyur Selvanambi Ravikumar, Sivaraman Kanthasamy,
Volume 18, Issue 4 (12-2021)
Abstract
The effect of pouring temperature while preparing Al SiC metal matrix composites, with additional benefits of magnesium and copper through stir casting technique were investigated. The composites were fabricated by mixing 12 wt% of SiC reinforcements, 4 wt% magnesium and 2 wt% copper into 6061 aluminium alloy melt at different pouring temperatures (630 ºC, 670 ºC and 710ºC). The addition of magnesium will enhance the wettability of the SiC particles with Al matrix and subsequently increase its interface bonding strength. The inclusion of copper has considerable improvement in strength and hardness of the composite. The microstructure and mechanical properties (tensile strength and hardness) of the Al MMC are evaluated with the corresponding processing parameter, specifically pouring temperature of the cast composite. The metallurgical characterization utilizing optical and scanning electron microscope were observed for the prepared composites. The coarse microstructure and homogenous distribution of alloying elements along with SiC particles were appeared within dendrite structures of the Al SiC composites. The SiC particles has effectively distributed and produced better bonding strength in composites prepared with 670ºC pouring temperature. Higher tensile strength and maximum hardness have occurred in composite at pouring temperature of 670ºC as compared to other composites. The mechanical properties were lower in composites prepared using lesser pouring temperature (630ºC) and significantly decreased for higher pouring temperature (710ºC) of the composites.
Mohammad Alipour,
Volume 20, Issue 2 (6-2023)
Abstract
This study was undertaken to investigate the influence of graphene nano sheets on the structural characteristics and dry sliding wear behaviour of Al-5Cu-1Mg aluminium alloy. The optimum amount of GNPs for proper grain refining was selected as 0.5 wt.%. T6 heat treatment was applied for all specimens before wear testing. Significant improvements in wear properties were obtained with the addition of GNPs combined with T6 heat treatment. Dry sliding wear performance of the alloy was examined in normal atmospheric conditions. The experimental results showed that the T6 heat treatment considerably improved the resistance of Al-5Cu-1Mg aluminium alloy to the dry sliding wear. The results showed that dry sliding wear performance of without T6 microstructure specimens was a lower value than that of with T6 specimens.
Elham Ghasemi, Majid Tavoosi, Ali Ghasemi, Mohammad Loghman Estarki,
Volume 20, Issue 2 (6-2023)
Abstract
In the present study, the structural and magnetic characteristics of Fe-Co-Cr system, with 28 at. % of Cr content, during casting, solutioning and thermo-magnetic treatment has been investigated. Based on results, the formation of single α-phase solid solution in the Fe72-xCoxCr28 (10The Co content had negligible effects on magnetic characteristics of Fe62Co10Cr28, Fe60Co12Cr28 and Fe58Co14Cr28 alloys. Fe72-xCoxCr28 (10 with a constant Cr content of about 28 at. %, were outside the miscibility gap in the equilibrium phase diagram, and therefore TMT had no effect on the final magnetic properties.
Mohammad Porhonar, Yazdan Shajari, Seyed Hossein Razavi, Zahra-Sadat Seyedraoufi,
Volume 20, Issue 3 (9-2023)
Abstract
In this research, after pressing in a cylindrical mold, the AA 7075 alloy swarf was melted and cast in a wet sand mold. After rolling and cutting, sheets with two different thicknesses of 6 and 20 mm were obtained. The sheets after homogenization were solutionized at 485°C for 30 and 90 minutes, respectively, due to differences in thickness and thermal gradients. The solutionized samples were quenched in 3 polymer solutions containing 10, 30, and 50% Poly Alekylene Glycol. The results showed that melting, casting, rolling, and heat treatment of AA7075 alloy swarf similar properties to this alloy is achievable. Microstructural studies by optical microscopes (OM), Field Emission Scanning Electron Microscopy (FESEM), and X-ray diffraction (XRD) showed that by increasing the quenching rate after the solutionizing process, precipitation increases during aging. The tensile test results indicated that as the quench rate and internal energy increase, the diffusion driving force would increase the precipitation of alloying elements. Hence, this leads to an increase in hardness and reduction of its strain after aging.
Israa Khahtan Sabree, Batool Abd Aladel Jabar,
Volume 20, Issue 3 (9-2023)
Abstract
Abstract. Hydroxyapatite (HA) scaffold is commonly used in the applications of bone tissue engineering due to its bioactivity and equivalent chemical composition to the inorganic constituents of human bone. The present study focused on the fabrication of porous 3D hydroxyapatite scaffold which was modified by polymer coating as a successful strategy to improve the mechanical properties. A 3D porous hydroxyapatite scaffolds were fabricated by gel-casting method by using freshly extracted egg yolk (EY) with (50 and 60)wt% of HA powder. To enhance the mechanical properties, composite PVA/ HA scaffolds were produced by using dip coating in Polyvinyl alcohol (PVA). Fourier transform infrared spectroscopy (FTIR) was used to recognize the functional group associated with the hydroxyapatite scaffolds before and after PVA coating. The physical (density and porosity) and mechanical (compressive strength and elastic modulus) properties were investigated before and after coating. SEM was used to inspect the surface morphology and pore modification of the scaffolds. Wettability was determined by using a water contact angle to analyze the scaffold hydrophobicity. Surface roughness was studied by atomic force microscopy (AFM). It was revealed that the scaffold porosity decreased with increase solid loading of HA powder in the gel and after PVA coating. The findings showed that PVA coating improved mechanical strength of scaffold to be double by covering the small pores and filling microcracks sited on the scaffold strut surfaces, inducing a crack bridging mechanism. The scaffolds’ strength was in the range of trabecular bone strength. This indicates non-load bearing applications.
