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K S Pandey - One of the best experts on this subject based on the ideXlab platform.
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phenomenon of instantaneous strain hardening behaviour of sintered al fe Composite Preforms during cold axial forming
2007Co-Authors: R Narayanasamy, N Selvakumar, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms in order to evaluate their work-hardening characteristics. Preforms of 92% of theoretical density, with two initial aspect ratios were prepared using a suitable die-set assembly on a 0.6 MN capacity hydraulic press. Sintering was carried out in an electric muffle furnace for a period of 1 h at 520 °C. Each sintered compact was subjected to incremental compressive loading after each step of deformation. The instantaneous strain-hardening exponent instantaneous strain-hardening exponent (ni) and strength coefficient instantaneous strength coefficient (ki) of the Al–Fe Composite Preforms were calculated and found to be reached the peak value when the deformation or packing density is at low value. Further, it has been observed that the value of ni and ki decreased and found to be constant It has further been established that the iron particle-size of the Preforms played a predominant role in influencing both ni and ki.
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modelling the effect of particle size and iron content on forming of al fe Composite Preforms using neural network
2007Co-Authors: N Selvakumar, P. Radha, R Narayanasamy, P Ganesan, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms inorder to model and analyse the formability by simulation using neural network (NN). A model has been developed with a radial basis NN algorithm. The data used were collected by the experimental set up in the laboratory for the sintered Al–Fe Composites with the various preform densities, the particle sizes and the aspect ratios. The network is trained to predict the forming characteristics such as the axial stress, the hoop stress, the hydrostatic stress and the Poisson ratio. In addition to that, the value of strain hardening coefficients such as instantaneous strength coefficient ( k i ) and instantaneous strain hardening exponent ( n i ) is also simulated to find the effect of particle size and the percent of iron content on formability. Regression analysis has confirmed a good agreement between the predicted and the experimental data with least error and hence this approach helps to facilitate a knowledge base in order to generate advice for the designer at the earlier stages of design so that concurrent engineering practices can be made.
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some aspects of workability studies on hot forging of sintered high strength 4 titanium carbide Composite steel Preforms
2006Co-Authors: R Narayanasamy, V Senthilkumar, K S PandeyAbstract:Abstract The aim of the paper is the study of workability of Fe–1.0% C–4% TiC steel Composite during hot upsetting. Ductile fracture is the most common failure acting in bulk forming process. The formability during hot upsetting depends on the temperature, strain and strain rate. A complete experimental investigation of the workability behaviour of Fe–1.0% C–4% TiC steel Composite was performed under the triaxial stress state condition. Hot upsetting of Fe–1.0% C–4% TiC steel Composite Preforms was carried out at a temperature of 1120 °C and the formability behaviour of the same at triaxial stress state condition was determined. The curves plotted for different Preforms were analysed and the relationship between the axial strain and the formability stress index were obtained. A relationship between the relative density and the axial strain was also established. A particular attempt was made to relate the various stress ratio parameters, namely, (σθ/σeff), (σm/σeff) and (σz/σeff) with the relative density.
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some aspects of work hardening in sintered aluminium iron Composite Preforms during cold axial forming
1998Co-Authors: R Narayanasamy, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered aluminium–iron Composite Preforms in order to evaluate their work-hardening characteristics. The effect of the iron content, the iron particle-size range and the initial aspect ratio of the Preforms on work hardening has been investigated thoroughly. Analysis of the experimental data has shown that the strain-hardening exponent n increased with decreasing values of the iron powder particle-size range, also being found to be greater for lower aspect ratio Preforms compared to higher aspect ratio Preforms. Irrespective of the initial aspect ratio and the iron content, the finer iron particle dispersoids showed an enhanced rate of work hardening, whereas a minimum level was shown by coarser iron particle-size dispersoids. The strength coefficient K was found to increase with decreasing iron particle-size range in the aluminium matrix. Both n and K values were found to decrease when the dispersed iron-particle range was greater (as in the present investigation). Further, it has been found that the rate of change of the n and K values were not the same for both of the aspect ratios of the Preforms tested: indeed, a pronounced difference existed. This has established that the initial geometry of the P/M Preforms plays a predominant role in influencing both n and K . In general, as the iron content in the aluminium matrix was increased, K was found to increase also, irrespective of the iron particle-size and the initial aspect ratio.
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strain hardening behaviour in sintered aluminium 3 5 alumina Composite Preforms during axial compression with and without annealing
1998Co-Authors: A J R Inigoraj, R Narayanasamy, K S PandeyAbstract:Abstract The present investigation has been undertaken to evaluate the strain-hardening phenomenon experienced in sintered aluminium–3.5% alumina Composite Preforms during axial compression tests. Powder Preforms of three different initial density ratios, namely 0.75, 0.80 and 0.90, with three initial aspect ratios for each density level were prepared using a suitable die-set assembly on a 0.60 MN capacity hydraulic press. Sintering was carried out in an electric muffle furnace for a period of 90 min at 550°C in a nitrogen atmosphere. Each sintered compact was subjected to incremental compressive loading with and without annealing after each step of deformation. The annealing operation was carried out in a furnace at 200°C for 30 min in a nitrogen atmosphere. The strain-hardening exponent n and strength coefficient K were obtained for each initial preform and for each aspect ratio. Analysis of the experimental data shows the existence of empirical relationships between the material parameters namely, n values and K values and the ratio of the initial preform densities to the theoretical density. Further, it was found that n consists of two segments, one representing the work hardening of the matrix material and the other due to densification. It has been also established that a power-law relationship exists between K and the percent fractional theoretical density %( ρ d / ρ th ).
R Narayanasamy - One of the best experts on this subject based on the ideXlab platform.
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microstructure cold workability and strain hardening behavior of trimodaled aa 6061 tio2 nanoComposite prepared by mechanical alloying
2011Co-Authors: S Sivasankaran, K Sivaprasad, R NarayanasamyAbstract:Abstract In the present work, the improvement of compressive ductility while maintaining high strength and toughness for nanocrystalline materials by cold upsetting (incremental loads) of bulk trimodaled Composite was studied. Mechanically alloyed nanocrystalline ( NC ) AA 6061 alloy powders reinforced with nano TiO 2 were blended with 0, 5, 10, 15, 20, 25, and 30 wt.% coarse grain ( CG ) elemental powders related to AA 6061 alloy composition to produce trimodal microstructure. The synthesized Composite Preforms were characterized by optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffraction. The room temperature compressive deformation behavior was evaluated under triaxial stress state condition. With increasing percentage of CG phase in the nanoComposite, the gradual improvement in compressive ductility was observed at the cost of a small amount of strength but it favored the ease of deformation. The 15% CG trimodal Composite exhibited an extremely high compressive strength of 935 MPa due to non-coalescence of individual CG particles and effective load transfer occurred in multi scale microstructures. But the 30% CG trimodal Composite showed an incremental compressive ductility of around 16% while sacrificing a small amount of strength (845 MPa) and this Composite displayed improved toughness (area under true effective stress and true effective strain curve) of over 600% than nanoComposite (0% CG ). Also, the percentage cold workability of 30% CG Composite was six times higher than that of 0% CG Composite. Hence, the 30% CG trimodal Composite was observed to be the good one as it exhibited a better strain hardening behavior while maintaining considerable strength and toughness.
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phenomenon of instantaneous strain hardening behaviour of sintered al fe Composite Preforms during cold axial forming
2007Co-Authors: R Narayanasamy, N Selvakumar, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms in order to evaluate their work-hardening characteristics. Preforms of 92% of theoretical density, with two initial aspect ratios were prepared using a suitable die-set assembly on a 0.6 MN capacity hydraulic press. Sintering was carried out in an electric muffle furnace for a period of 1 h at 520 °C. Each sintered compact was subjected to incremental compressive loading after each step of deformation. The instantaneous strain-hardening exponent instantaneous strain-hardening exponent (ni) and strength coefficient instantaneous strength coefficient (ki) of the Al–Fe Composite Preforms were calculated and found to be reached the peak value when the deformation or packing density is at low value. Further, it has been observed that the value of ni and ki decreased and found to be constant It has further been established that the iron particle-size of the Preforms played a predominant role in influencing both ni and ki.
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modelling the effect of particle size and iron content on forming of al fe Composite Preforms using neural network
2007Co-Authors: N Selvakumar, P. Radha, R Narayanasamy, P Ganesan, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms inorder to model and analyse the formability by simulation using neural network (NN). A model has been developed with a radial basis NN algorithm. The data used were collected by the experimental set up in the laboratory for the sintered Al–Fe Composites with the various preform densities, the particle sizes and the aspect ratios. The network is trained to predict the forming characteristics such as the axial stress, the hoop stress, the hydrostatic stress and the Poisson ratio. In addition to that, the value of strain hardening coefficients such as instantaneous strength coefficient ( k i ) and instantaneous strain hardening exponent ( n i ) is also simulated to find the effect of particle size and the percent of iron content on formability. Regression analysis has confirmed a good agreement between the predicted and the experimental data with least error and hence this approach helps to facilitate a knowledge base in order to generate advice for the designer at the earlier stages of design so that concurrent engineering practices can be made.
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some aspects of workability studies on hot forging of sintered high strength 4 titanium carbide Composite steel Preforms
2006Co-Authors: R Narayanasamy, V Senthilkumar, K S PandeyAbstract:Abstract The aim of the paper is the study of workability of Fe–1.0% C–4% TiC steel Composite during hot upsetting. Ductile fracture is the most common failure acting in bulk forming process. The formability during hot upsetting depends on the temperature, strain and strain rate. A complete experimental investigation of the workability behaviour of Fe–1.0% C–4% TiC steel Composite was performed under the triaxial stress state condition. Hot upsetting of Fe–1.0% C–4% TiC steel Composite Preforms was carried out at a temperature of 1120 °C and the formability behaviour of the same at triaxial stress state condition was determined. The curves plotted for different Preforms were analysed and the relationship between the axial strain and the formability stress index were obtained. A relationship between the relative density and the axial strain was also established. A particular attempt was made to relate the various stress ratio parameters, namely, (σθ/σeff), (σm/σeff) and (σz/σeff) with the relative density.
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deformation behavior of cold upset forming of sintered al fe Composite Preforms
2005Co-Authors: N Selvakumar, R NarayanasamyAbstract:Cold upsetting experiments were carried out on sintered Al-Fe Preforms in order to evaluate their deformation characteristics. The effects of iron content and initial fractional density of the Preforms on deformation behavior have been investigated thoroughly by using graphite as a lubricant. Cylindrical Preforms with different initial theoretical density and aspect ratio (0.75) were prepared using a suitable die, a punch and a die bottom insert on a 1.0 MN capacity Universal testing machine. The Preforms were well covered with dry fine silica sand and sintered in an electric muffle furnace at 550 ±10°C for a period of 1 h and then furnace cooled. Cold deformation experiments were carried out in several steps. Dimensions such as height, contact, and bulged diameters and densities were measured for each test. In general, each compact was subjected to an incremental compressive loading in steps of 0.005 MN until fine cracks appeared on its free surface. Analysis of the experimental data has shown that the power law relationship between fractional theoretical density (ρ f /ρ th ) and e (e z -e θ) has been established. This remained valid for 0-8% iron content and all initial preform densities. Further it was found that the Preforms of higher iron content shows higher values of deformation properties like the axial stress and the Poisson's ratio than less/without iron Preforms provided that the initial fractional density taken is kept constant.
N Selvakumar - One of the best experts on this subject based on the ideXlab platform.
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electrical resistivity wear map and modeling of extruded tungsten reinforced copper Composite
2014Co-Authors: S. C. Vettivel, N. Leema, N Selvakumar, Haiter A LeninAbstract:Abstract The present work includes the effect of W addition in improving the properties of Cu with the help of high-energy mechanical alloying. Composite Preforms of (5–15 W) with copper were fabricated by Powder Metallurgy (P/M) method. The Preforms were sintered at 850 °C, subsequently the furnace was cooled and again the specimens were hot extruded to get 92% preform density. Four point probe tester, Scanning Electron Microscope, Energy Dispersive Spectrum and pin on-disc system were used to evaluate electrical conductivity, characterization and tribological property of Cu–W Composite respectively. The various stages in dominant oxidation and delamination wear mechanism was clearly discussed. The wear rate and coefficient of friction decreased with increase in load and sliding distance. Design expert software was used to develop contour map, mathematical model and useful conclusions were made.
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investigation of cu sic Composite Preforms during cold upsetting
2011Co-Authors: M Sumathi, N SelvakumarAbstract:Cold upsetting experiments were carried out on sintered Cu-SiC Preforms in order to evaluate their deformation characteristics. Powder Preforms of 0.85, 0.90, and 0.95 initial preform density and 0.60 of initial aspect ratio were subjected to incremental compressive loading of 0.02 MN until fracture appeared at free surfaces. The effects of silicon carbide content and initial fractional density of the Preforms on deformation behavior have been investigated thoroughly by using Zinc stearate as a lubricant. Dimensions such as height, contact, and bulged diameters, and densities were measured for each test. Analysis of the experimental data has shown the power law relationship between fractional theoretical density and e (ϵ z −ϵθ). Further, it was found that the Preforms of lower silicon carbide content show higher values of deformation properties like the axial stress and the Poisson's ratio than higher silicon carbide Preforms, provided that the initial fractional density taken is kept constant.
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phenomenon of instantaneous strain hardening behaviour of sintered al fe Composite Preforms during cold axial forming
2007Co-Authors: R Narayanasamy, N Selvakumar, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms in order to evaluate their work-hardening characteristics. Preforms of 92% of theoretical density, with two initial aspect ratios were prepared using a suitable die-set assembly on a 0.6 MN capacity hydraulic press. Sintering was carried out in an electric muffle furnace for a period of 1 h at 520 °C. Each sintered compact was subjected to incremental compressive loading after each step of deformation. The instantaneous strain-hardening exponent instantaneous strain-hardening exponent (ni) and strength coefficient instantaneous strength coefficient (ki) of the Al–Fe Composite Preforms were calculated and found to be reached the peak value when the deformation or packing density is at low value. Further, it has been observed that the value of ni and ki decreased and found to be constant It has further been established that the iron particle-size of the Preforms played a predominant role in influencing both ni and ki.
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modelling the effect of particle size and iron content on forming of al fe Composite Preforms using neural network
2007Co-Authors: N Selvakumar, P. Radha, R Narayanasamy, P Ganesan, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms inorder to model and analyse the formability by simulation using neural network (NN). A model has been developed with a radial basis NN algorithm. The data used were collected by the experimental set up in the laboratory for the sintered Al–Fe Composites with the various preform densities, the particle sizes and the aspect ratios. The network is trained to predict the forming characteristics such as the axial stress, the hoop stress, the hydrostatic stress and the Poisson ratio. In addition to that, the value of strain hardening coefficients such as instantaneous strength coefficient ( k i ) and instantaneous strain hardening exponent ( n i ) is also simulated to find the effect of particle size and the percent of iron content on formability. Regression analysis has confirmed a good agreement between the predicted and the experimental data with least error and hence this approach helps to facilitate a knowledge base in order to generate advice for the designer at the earlier stages of design so that concurrent engineering practices can be made.
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deformation behavior of cold upset forming of sintered al fe Composite Preforms
2005Co-Authors: N Selvakumar, R NarayanasamyAbstract:Cold upsetting experiments were carried out on sintered Al-Fe Preforms in order to evaluate their deformation characteristics. The effects of iron content and initial fractional density of the Preforms on deformation behavior have been investigated thoroughly by using graphite as a lubricant. Cylindrical Preforms with different initial theoretical density and aspect ratio (0.75) were prepared using a suitable die, a punch and a die bottom insert on a 1.0 MN capacity Universal testing machine. The Preforms were well covered with dry fine silica sand and sintered in an electric muffle furnace at 550 ±10°C for a period of 1 h and then furnace cooled. Cold deformation experiments were carried out in several steps. Dimensions such as height, contact, and bulged diameters and densities were measured for each test. In general, each compact was subjected to an incremental compressive loading in steps of 0.005 MN until fine cracks appeared on its free surface. Analysis of the experimental data has shown that the power law relationship between fractional theoretical density (ρ f /ρ th ) and e (e z -e θ) has been established. This remained valid for 0-8% iron content and all initial preform densities. Further it was found that the Preforms of higher iron content shows higher values of deformation properties like the axial stress and the Poisson's ratio than less/without iron Preforms provided that the initial fractional density taken is kept constant.
P. Radha - One of the best experts on this subject based on the ideXlab platform.
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Characterization, pore size measurement and wear model of a sintered Cu–W nano Composite using radial basis functional neural network
2015Co-Authors: N. Leema, S. C. Vettivel, P. Radha, H. Khanna NehemiahAbstract:Cu–(5–20%) W Composite Preforms, with a density of 94% were prepared through mechanical milling, mixing, compaction, sintering and hot extrusion. The X-ray Diffraction analysis, Particle Size analysis, Transmission Electron Microscope, Scanning Electron Microscope and Energy Dispersive Spectrum were used for the characterization studies. The pore size during different sintering atmospheres and the pore size reduction during extrusion, were studied through Auto CAD 2010 software. The wear experiments were conducted using the pin-on-disc wear tester. The various regions in the wear mechanisms were identified through the wear distribution map. The Radial Basis Functional Neural Network has been used in an attempt to predict the mechanical and tribological behavior of Composites, and useful conclusions have been made.
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modelling the effect of particle size and iron content on forming of al fe Composite Preforms using neural network
2007Co-Authors: N Selvakumar, P. Radha, R Narayanasamy, P Ganesan, K S PandeyAbstract:Abstract Cold upsetting experiments were carried out on sintered Al–Fe Composite Preforms inorder to model and analyse the formability by simulation using neural network (NN). A model has been developed with a radial basis NN algorithm. The data used were collected by the experimental set up in the laboratory for the sintered Al–Fe Composites with the various preform densities, the particle sizes and the aspect ratios. The network is trained to predict the forming characteristics such as the axial stress, the hoop stress, the hydrostatic stress and the Poisson ratio. In addition to that, the value of strain hardening coefficients such as instantaneous strength coefficient ( k i ) and instantaneous strain hardening exponent ( n i ) is also simulated to find the effect of particle size and the percent of iron content on formability. Regression analysis has confirmed a good agreement between the predicted and the experimental data with least error and hence this approach helps to facilitate a knowledge base in order to generate advice for the designer at the earlier stages of design so that concurrent engineering practices can be made.
Ananthanarayanan Rajeshkannan - One of the best experts on this subject based on the ideXlab platform.
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Formability of Sintered Al, Al-Cu and Al-Cu-TiC Composites during Cold Upsetting
2020Co-Authors: Khan M.n., Narayan Sumesh, Ananthanarayanan Rajeshkannan, Jeevanantham A.k.Abstract:This work examines the formability characteristics of sintered Aluminium (Al) Composites during cold upsetting. Formability evaluates the extent of deformation that materials can withstand without the initiation of cracks or before yielding in the forming process. As such, formability studies are critical in order to produce defect free components. This study is particularly necessary for parts produced by the Powder metallurgy (PM) technique, considering the high volume of pores present in PM components even after the sintering process. Thus, this study experimentally investigates the effects of different weight percent of Copper (Cu) and Titanium carbide (TiC) addition to the Al Composite Preforms. To determine the formability behavior; Al, Al-3Cu, Al-6Cu, Al-3Cu-2TiC, Al-3Cu-4TiC, Al-6Cu-2TiC and Al-6Cu-4TiC with aspect ratios (height/ diameter) of 0.45 and 0.9 were cold upset under different frictional conditions (nil/ no lubricant, graphite lubricant and zinc stearate lubricant). Consequently, the effects of reinforcement addition to the Al Composite and initial preform geometry on the relative density, R, are investigated. Moreover, other influencing physical parameters such as axial stress and the formability stress index, β are also graphically presented. It has been established from this study that the nil lubricated lower aspect ratio TiC containing compacts generally achieved improved densification, higher values of axial stresses and consequently better formability. However, the addition of Cu and TiC limits the height strain to fractur
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Formability of Sintered Al, Al-Cu and Al-Cu-TiC Composites during cold upsetting
2020Co-Authors: Khan M.n., Narayan Sumesh, Ananthanarayanan Rajeshkannan, Jeevanantham A.k.Abstract:This work examines the formability characteristics of sintered Aluminium (Al) Composites during cold upsetting. Formability evaluates the extent of deformation that materials can withstand without the initiation of cracks or before yielding in the forming process. As such, formability studies are critical in order to produce defect free components. This study is particularly necessary for parts produced by the Powder metallurgy (PM) technique, considering the high volume of pores present in PM components even after the sintering process. Thus, this study experimentally investigates the effects of different weight percent of Copper (Cu) and Titanium carbide (TiC) addition to the Al Composite Preforms. To determine the formability behavior; Al, Al-3%Cu, Al-6%Cu, Al-3%Cu-2%TiC, Al-3%Cu-4%TiC, Al-6%Cu-2%TiC and Al-6%Cu-4%TiC with aspect ratios (height/ diameter) of 0.45 and 0.9 were cold upset under different frictional conditions (nil/ no lubricant, graphite lubricant and zinc stearate lubricant). Consequently, the effects of reinforcement addition to the Al Composite and initial preform geometry on the relative density, R, are investigated. Moreover, other influencing physical parameters such as axial stress and the formability stress index, β are also graphically presented. It has been established from this study that the nil lubricated lower aspect ratio TiC containing compacts generally achieved improved densification, higher values of axial stresses and consequently better formability. However, the addition of Cu and TiC limits the height strain to fracture
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Workability of sintered Aluminium Composite Preforms of varying Cu and TiC contents during cold deformation
2019Co-Authors: Khan, Mohammed N., Narayan Sumesh, Ananthanarayanan RajeshkannanAbstract:The present research investigates the workability behaviour of sintered Aluminium (Al) Composites under cold deformation. Workability measures the level of deformation that materials can sustain prior to failure in the forming process. The effects of different weight percent of Copper (Cu) and Titanium carbide (TiC) addition to the Al Composite Preforms were experimentally determined. Al, Al-3%Cu, Al-3%Cu-2%TiC and Al-3%Cu-4%TiC were cold upset under different frictional conditions (nil/no lubricant, graphite lubricant and zinc stearate lubricant) and aspect ratios (0.45 and 0.9) to determine the workability behaviour. The curves were plotted and analysed for different Preforms. The effects of the reinforcement addition to the Al Composite and initial preform geometry on the relative density (R), and other influencing physical parameter such as axial stress and the formability stress index, β is presented
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Influence of process parameters on the workability characteristics of sintered Al and Al – Cu Composites during cold deformation
2019Co-Authors: Khan, Mohammed N., Narayan Sumesh, Ananthanarayanan RajeshkannanAbstract:An experimental investigation on the process parameters affecting the workability characteristics of sintered aluminium (Al) and aluminium–copper (Al–Cu) Composites during cold forging has been carried out. Cylindrical billets of Al, Al–3%Cu and Al–6%Cu with height to diameter ratio (aspect ratio) of 0.45 and 0.9 were cold deformed under three different frictional conditions (nil/no lubricant, graphite lubricant and zinc stearate lubricant). As such, some important process parameters influencing the workability of these Composites such as the initial preform geometry and different volume percent of Cu addition to the Al Composite Preforms on the relative density, R and physical parameters such as stresses affecting the workability stress index, β have been investigated. Also, the effects of the different frictional conditions on the same are presented. It was established that the nil/no lubricant condition and Preforms of the lower aspect ratio yielded improved densification, higher values of stresses and better workability. Furthermore, Al–Cu Composites were developed to yield better combined properties such as improved densification and workability than monolithic Al. However, the addition of Cu reduced the axial strain to fracture. As such, a decrease in the densification and the workability characteristics was noted with an increase in the volume percent of Cu