Workability studies on Al+2.5%TiO2+Gr powder metallurgy composites during cold upsetting

Abstract

Al+2.5%TiO2+Gr composites were synthesized through powder metallurgy technique and their workability behavior has been studied under tri-axial stress state condition. The powders were compacted using suitable punch and die in 400 kN hydraulic press and sintered at a temperature of about 590 ºC for a period of 3 hours in an electric muffle furnace. The sintered preforms were characterized by XRD and SEM analysis. Then the preforms were subjected to incremental compressive loading of 10 kN until the cracks found at the free surface. The true axial stress (σz), true hoop stress (σ}), true hydrostatic stress (σσm) true effective stress (σeff), formability stress index (β) and stress ratio parameters [(σz/σeff), (σm/σeff), (σ}/σeff)] were calculated for all the preforms and these are correlated with the true axial strain (e z). It is inferred that, the addition of TiO2 and Gr to the Al matrix material increases the stress ratio parameters and formability stress index (β). A hardness test was also conducted for sintered and cold forged preforms and results are reported.

metal matrix composites; cold upsetting; powder metallurgy

REGULAR ARTICLES

Workability studies on Al+2.5%TiO₂+Gr powder metallurgy composites during cold upsetting

Manickam Ravichandran^I; Abdullah Naveen SaitI, ^*; Veeramani Anandakrishnan^II

^IDepartment of Mechanical Engineering, Chendhuran College of Engineering and Technology, Pudukkottai - 622507, India

^IIDepartment of Production Engineering, National Institute of Technology, Tiruchirappalli - 620015, India

ABSTRACT

Al+2.5%TiO₂+Gr composites were synthesized through powder metallurgy technique and their workability behavior has been studied under tri-axial stress state condition. The powders were compacted using suitable punch and die in 400 kN hydraulic press and sintered at a temperature of about 590 °C for a period of 3 hours in an electric muffle furnace. The sintered preforms were characterized by XRD and SEM analysis. Then the preforms were subjected to incremental compressive loading of 10 kN until the cracks found at the free surface. The true axial stress (σ_z), true hoop stress (σ_ө), true hydrostatic stress (^σσ_m) true effective stress (σ_eff), formability stress index (β) and stress ratio parameters [(σ_z/σ_eff), (σ_m/σ_eff), (σ_ө/σ_eff)] were calculated for all the preforms and these are correlated with the true axial strain (e_z). It is inferred that, the addition of TiO₂ and Gr to the Al matrix material increases the stress ratio parameters and formability stress index (β). A hardness test was also conducted for sintered and cold forged preforms and results are reported.

Keywords: metal matrix composites, cold upsetting, powder metallurgy

1. INTRODUCTION

The powder metallurgy process is replacing traditional metal forming operations because of its low relative energy consumption, high material utilization, and low capital cost¹. Also the uniformity in reinforcement distribution can be achieved by the powder metallurgy process to produce porous structures and this improves structural properties and also reproducibility^2,3. Among all composite materials, metal matrix materials are widely used in various applications in which Aluminum based Metal Matrix Composites (MMCs) are widely used in structural applications in the aerospace and automotive industries due to their high strength-to-weight ratio⁴. Furthermore Aluminium Metal Matrix Composites are mostly used for producing porous parts like bearings because of its porous structure and it is suitable to serve as self-lubricated bearings⁵. Nowadays AMCs are synthesized with various reinforcements such as graphite, SiC, Al₂O₃, TiC, VC, AlN, B₄C, Si₃N₄, TiB₂, AlB₂ and MgB₂^[6-16]. Even though Titanium dioxide (TiO₂) possesses high hardness and modulus with superior corrosion resistance and wear resistance, it is not concentrated much by the recent researchers¹⁷. Al-TiO₂ composite system is one of the interesting material systems, and it has been produced by vortex casting and squeeze casting process and its properties are reported¹⁸. Also Somaye Alamolhoda et al. produced TiAl/Al₂O₃ composite from Al-TiO₂ powder mixtures using high-energy planetary ball mill through mechanical activation mechanism¹⁹. It is proved that the addition of hard ceramic reinforcement particles increases wear resistance and hardness. However, the composites containing hard ceramic particles lack a solid lubricant, such as graphite²⁰. Aluminium alloy - graphite particulate composites (Al/Gr MMCs) exhibit improvement in mechanical properties, low friction and wear, reduced temperature rise at the wearing contact surface, excellent anti-seizure effects, improved machinability, low thermal expansion and high damping capacity because of graphite reinforcement²¹. Hybrid aluminium matrix composites are produced with the addition of solid lubricant particles such as graphite along with hard ceramic particles to improve the tribological and self-lubricating properties of the composites²². The main drawback of the powder metallurgy process is porosity in components after sintering. To decrease the porosity, many secondary processes are carried out to powder metallurgy components, among which powder forging is particularly suitable because of its cost and material saving advantages as well as the high production rates and property enhancement²³. Narayanasamy et al.²⁴ defined the term workability as the capacity of a material to withstand the induced internal stresses of forming before the splitting of material occurs. They also reported that, the workability of a material purely depends on the amount of ductile fracture presented in the material²⁴. The workability behavior for various ferrous and non- ferrous alloys and composites (Al-3.5%Al₂O₃, Al - 5%SiC, Al-Fe, Fe-4%TiC and Fe-0.35C) have been studied by various researchers and reported under plane stress, uni-axial stress and tri-axial stress state conditions during cold as well as hot forging process^25-30.

In the present study, Al matrix composites with 2.5 weight percentage of TiO₂ and 2 & 4 weight percentage of graphite was synthesized through powder metallurgy route. The SEM and XRD analyses were carried out for the sintered powder metallurgy preforms. The as-sintered pure Aluminium, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr, and Al+2.5%TiO₂+4%Gr compacts were cold upset forged to study the forming behavior. The various stresses like true axial stress (σ_z), true hoop stress (σ_ө) and true hydrostatic stress (σ_m) induced during cold upsetting have been correlated with true axial strain (ε_z). The formability stress index (β) and stress ratio parameters (σ_z/σ_eff), (σ_m/σ_eff) and (σ_ө/σ_eff) were also correlated with the true axial strain (ε_z).

2. EXPERIMENTAL DETAILS

2.1. Materials

Atomized aluminium (Al) powder of particle size less than 325 µm and the purity 99.7% supplied by Kemphasol, Mumbai, India was used as matrix material. The rutile grade of titanium dioxide (TiO₂) powder with an average particle size of 0.334 mm and purity 99.0% and graphite powders of size less than 10 mm supplied by the Acechemie (India) was used as reinforcements for the present work. The morphology of the as received Al powder particles is presented in Figure 1.

2.2. Blending, compaction and sintering

Al and TiO₂ powders are accurately weighed and blended in ball mill to yield the different composites namely, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr, and Al+2.5%TiO₂+4%Gr. The blending was carried out with balls and powders weight ratio of 5:1 and the speed of the drum was 100 rpm³¹ for a period of 10 hours³². XRD analysis for Al+2.5%TiO₂+2%Gr composite powders were carried out using PANalytical X'Pert X-ray diffractometer C_uKα target, (λ=1.5418 Å). The powder mixtures were compacted into cylindrical billets of diameter 24 mm and the height 12 mm using hydraulic press of 400 kN capacity. Graphite mixed with lubricant oil was used as lubricant during compaction process. An indigenously developed ceramic coating was applied on the free surfaces of the compacts to avoid oxidation of the Aluminium matrix composites and dried under room temperature for a period of 12 hours²⁴. The ceramic coated compacts were sintered in an electric muffle furnace in the temperature range of (590±10) °C for a period of 3 hours and cooled to room temperature in the furnace. The SEM analysis was carried out for the sintered preforms using Quanta 250 FEG and XRD analysis was conducted by XPERT-PRO diiffractometer.

2.3. Cold upsetting

The sintered preforms were cleaned and measurements such as initial height (H_o), diameter (D_o) and mass (m) were taken. The cold upsetting was carried out between two flat high speed steel dies with graphite lubricant at both of die contact surfaces, to ensure minimum friction. The incremental compressive load was applied on the cold upset specimen in steps of 10 kN, until fine cracks appeared on its free surface. Figure (2-4) shows the preforms before and after deformation. After each interval of loading dimensional changes in the specimen such as height after deformation (H_D), top contact diameter (D_TC), bottom contact diameter (D_BC), bulged diameter (D_B) and density of the preform (ρ_f) were measured. Archimedes principle was used to find the actual densities of the preforms after each step of deformation. The measured values were used to calculate the true axial stresses (σ_z), true hoop stress (σ_ө), true hydrostatic stress (σ_m), true effective stress (σ_eff), formability stress index (β) and true axial strain (ε_z). These workability parameters under tri-axial stress state conditions are calculated by using following expressions^24,25.

The true hoop strain (ε_θ) can be determined by the following expression,

D_o, initial dia ; D_B, bulge dia ; Dc, average surface contact dia

The true hydrostatic stress (σ_m) is given by,

The true hoop stress (σ_ө) can be expressed by,

Where α is Poisson's ratio

The true effective stress (σ_eff) is calculated by,

Where R is Relative Density of the preforms

The formability index (β) is given by,

Hardness tests have been conducted for sintered and cold forged pure Al, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr and Al+2.5%TiO₂+4%Gr powder metallurgy preforms in Rockwell hardness testing machine, with a load of 100 kg using 1/16 inch ball indenter. The mean values of at least five measurements conducted on different areas of each preforms was considered.

3. RESULTS AND DISCUSSIONS

3.1. SEM analysis of sintered powder metallurgy preforms

Figure 5(a-d) illustrates the SEM image of pure Al, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr and Al+2.5%TiO₂+4%Gr powder metallurgy sintered preforms. As can be seen, fine grain boundaries are formed in all composite preforms during sintering and pores also observed. From Figure 5(b-d), it can be observed that, the TiO₂ particles are embedded within the Al matrix. The graphite particles also distributed evenly in the Al matrix as well as around the TiO₂ particles as shown in Figure 5(c & d). Both the TiO₂ and Graphite reinforcements are acted as a pore closing agent and contributed to the decrease in porosity. It is very important that all particles should be homogeneously distributed in the mixture in order to obtain a good microstructure². Here the selection of ball milling parameters such as milling speed, milling time and ball to powder ratio are contributed to produce the compacts with uniform distribution of reinforcements.

3.2. XRD analysis

The XRD pattern of Al+2.5%TiO₂+2%Gr milled composite powders is presented in Figure 6. The XRD results confirmed the presence of TiO₂ and graphite particles in Aluminium matrix (JCPDS No. 80-1501). Figure 7 shows the XRD patterns of Pure Al, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr and Al+2.5%TiO₂+4%Gr powder metallurgy preforms sintered at 590 °C. The peaks of Al, TiO₂ (87-0920) and Gr (75-2078) were observed for the pure Al, Al+2.5%TiO₂ composite and hybrid composite preforms. The Al peaks in (111), (200), (220) & (311) plane, TiO₂ peaks in (101) & (200) plane and graphite peaks in (111) & (222) plane were observed. From the XRD pattern it is also observed that the peak broadening of Al increases with the addition of TiO₂ and Gr reinforcements. Also the increased peak broadening was observed for sintered preforms. The reason could be, during sintering the Al matrix becomes solid solution structure. Also it has been observed from the XRD patterns, no intermetallic compounds were formed in as-milled and as-sintered conditions.

3.3. Stress analysis on powder metallurgy preforms

The true axial stress (σ_z) versus true axial strain (ε_z) curve of pure Al, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr and Al+2.5%TiO₂+4%Gr powder metallurgy compacts are presented in Figure 8. The true axial stress (σ_z) increases for any given true axial strain (ε_z) while increasing the reinforcement contents (TiO₂ & Gr) in the compacts. The addition of 2.5 weight percentage of TiO₂ in the pure Al matrix shows the increase in true axial stress (σ_z), also the addition of 2% and 4% of Graphite to the Al+2.5%TiO₂ composite further increases the axial applied load for the same level of true axial strain (ε_z). The increase in true axial stress (σ_z) is because of addition of both TiO₂ and graphite reinforcements in Al matrix and it also contributes to the decrease in porosity. Narayanasamy et al. studied the workability behavior of Al-SiC composites and reported that, the SiC particulates obstruct the motion of dislocations and hence the stress required for further plastic deformation increases and the same author reported that fine graphite particles are contributed for the pore closing in powder metallurgy steel preforms^33,34. In the present study both TiO₂ and graphite reinforcement contributed for the pore closing and it increases the true axial stress (σ_z). The same behavior also observed for the graph drawn between the other stresses like true hoop stress (σ_ө) and true hydrostatic stress (σ_m) with true axial strain (ε_z) as shown in Figure 9 & 10. Addition of 2.5 weight percentage of TiO₂ to the Al matrix and addition of 2 & 4 weight percentage of graphite to the Al+2.5%TiO₂ composite increases true hoop stress (σ_ө) and true hydrostatic stress (σ_m) under tri-axial stress state conditions. Also higher true axial strain (better deformation) was observed for the pure Aluminium preforms with the lower applied stress, however for Al+2.5%TiO₂ composite and Al+2.5%TiO₂+2%Gr & Al+2.5%TiO₂+4%Gr hybrid composite preforms shows lower true axial strain (ε_z) with the higher applied stress because of obstacles created by the reinforcements for dislocation during plastic deformation.

3.4. Workability behavior of P/M Al-TiO2 composite preform

Figure 11 illustrates the graph between the formability stress index (β) and true axial strain (ε_z) for the pure Al, Al+2.5%TiO₂, Al+2.5%TiO₂+2%Gr and Al+2.5%TiO₂+4%Gr powder metallurgy preforms. It has been observed from the graph that, the formability stress index (β) increases with increase in true axial strain (ε_z) for all the preforms tested. Further the addition of 2.5 weight percentage of TiO₂ to the Al matrix and 2 & 4 weight percentage of graphite to the Al+2.5%TiO₂ composite increases the formability stress index (β). The reason for the increase in formability stress index (β) is due to the increase in relative density and true hydrostatic stress (σ_m) during cold upsetting of sintered composite preforms. These results are well agreed with findings of 4%TiC-Steel composites tested under tri-axial stress state condition²⁹.

Figure 12-14 shows the graph between the stress ratio parameters [(σ_z/σ_eff), (σ_m/σ_eff) & (σ_ө/σ_eff)] and the true axial strain (ε_z) for all the preforms and it has been observed that the stress ratio parameter also increases with increase in true axial strain (ε_z). The increase in weight percentage of reinforcements also increases the stress ratio parameters. The reason for the increase in all the stress ratio parameters could be the amount of porosity. The presence of pores in pure Aluminium preform was bigger and more than the composite preforms. The decrease in porosity of composite preforms increases the stress ratio parameters [(σ_z/σ_eff), (σ_m/σ_eff) & (σ_ө/σ_eff)]. The similar kind of trend was observed for all the three stress ratio parameters drawn against true axial strain (ε_z).

3.5. Hardness of the powder metallurgy preforms

Figure 15 shows the hardness of sintered and cold forged preforms. The hardness increases with the addition of 2.5 weight percentage of TiO₂ to the soft aluminium matrix. The brittle phase of TiO₂ contributed to the increase in hardness value. Zhangwei Wang et al. reported for Al-SiC composites that, the addition of SiC particles also increases the hardness of the composite³⁴. The addition of 2 weight percentage of graphite to the Al+2.5%TiO₂ composite increases the hardness. However, addition of 4 weight percentage of graphite decreases the hardness value of the composite. The hardness decreases with increasing graphite content, because of soft nature of graphite³⁵. Also the increased amount of graphite particles together with the increased tendency of crack initiation an propagation at the graphite-metal interface are the responsible for the decrease in hardness³⁶. The lower hardness values were obtained for sintered specimens and higher values are observed for the cold forged specimens, since the pores are closed and occupied by the reinforcements during cold upset forging. The maximum hardness values were obtained for the cold forged preforms containing 2.5 weight percentages of TiO₂ particles. The pore closing mechanism and presence of hard phase in the composite contributed to the increase in hardness after cold upsetting.

4. CONCLUSIONS

• Al+2.5%TiO

  ₂+Gr hybrid composite was synthesized through powder metallurgy technique and its workability behavior was studied during cold upsetting test under tri-axial stress condition.

• The sintered preforms were characterized by SEM and XRD analyses and it reveals that the uniform distribution of reinforcements (TiO

  ₂ & Gr). The true axial stress (σ

  _z), true hoop stress (σ

  _ө) and true hydrostatic stress (σ

  _m) increases with the addition of TiO

  ₂ and Gr particles in pure Al matrix during cold upsetting.

• The formability stress index (β) increases with the addition of 2.5 weight percentage of TiO

  ₂ and 2 & 4 weight percentage of Gr reinforcements in pure Al matrix during cold upsetting.

• The stress ratio parameters [(σ

  _z/σ

  _eff), (σ

  _θ/σ

  _eff) & (σ

  _m/σ

  _eff)] also increases with the addition of TiO

  ₂ and increase in weight percentage of graphite. It is also found to be higher for the preform containing 2.5 weight percentage of TiO

  ₂ and 4 weight percentages of graphite and lower for the pure Al preform.

• The addition of 2.5 weight percentage of TiO

  ₂ increases the hardness of the preforms and addition of 4 weight percentage of graphite to the Al+2.5%TiO

  ₂ composite decreases the hardness.

Received: December 20, 2013

Revised: November 17, 2014

• 1. Wang J and Danninger H. Dry sliding wear behavior of molybdenum alloyed sintered steels. Wear 1998; 222(1):49-56. http://dx.doi.org/10.1016/S0043-1648(98)00279-8
• 2. Torralba JM, Costa CE and Velasco F. P/M aluminum matrix composites: an overview. Journal of Materials Processing Technology 2003; 133(1-2):203-206. http://dx.doi.org/10.1016/S0924-0136(02)00234-0
• 3. Dewidar MM, Yoon H-C and Lim JK. Mechanical properties of metals for biomedical applications using powder metallurgy process: a review. Metals and Materials International 2006; 12(3):193-206. http://dx.doi.org/10.1007/BF03027531
• 4. Ahamed H and Senthilkumar V. Consolidation behavior of mechanically alloyed aluminum based nanocomposites reinforced with nanoscale Y2O3/Al2O3 particles. Materials Characterization 2011; 62(12):1235-1249. http://dx.doi.org/10.1016/j.matchar.2011.10.011
• 5. Hayajneh MT, Hassan AM and Mayyas AT Mohammed T. Artificial neural network modeling of the drilling process of self-lubricated aluminum/alumina/graphite hybrid composites synthesized by powder metallurgy technique. Journal of Alloys and Compounds 2009; 478(1-2):559-565. http://dx.doi.org/10.1016/j.jallcom.2008.11.155
• 6. Mahdavi S and Akhlaghi F. Effect of the graphite content on the tribological behavior of Al/Gr and Al/30SiC/Gr composites processed by In Situ Powder Metallurgy (IPM) method. Tribology Letters 2011; 44(1):1-12. http://dx.doi.org/10.1007/s11249-011-9818-2
• 7. Hassani A, Bagherpour E and Qods F. Influence of pores on workability of porous Al/SiC composites fabricated through powder metallurgy + mechanical alloying. Journal of Alloys and Compounds 2014; 591:132-142. http://dx.doi.org/10.1016/j.jallcom.2013.12.205
• 8. Vedani M, D'Errico FD and Gariboldi E. Mechanical and fracture behaviour of aluminium-based discontinuously reinforced composites at hot working temperatures. Composites Science and Technology 2006; 66(2):343-349. http://dx.doi.org/10.1016/j.compscitech.2005.04.045
• 9. Nemati N, Khosroshahi R, Emamy M and Zolriasatein A. Investigation of microstructure, hardness and wear properties of Al - 4.5 wt.% Cu - TiC nanocomposites produced by mechanical milling. Materials & Design 2011; 32(7):3718-3729. http://dx.doi.org/10.1016/j.matdes.2011.03.056
• 10. Ruiz-Navas EM, Fogagnolo JB, Velasco F, Ruiz-Prieto JM and Froyen L. One step production of aluminium matrix composite powders by mechanical alloying. Composites. Part A: Applied Science and Manufacturing 2006; 37(11):2114-2120. http://dx.doi.org/10.1016/j.compositesa.2005.11.016
• 11. Abdoli H, Salahi E, Farnoush H and Pourazrang K. Evolutions during synthesis of Al - AlN-nanostructured composite powder by mechanical alloying. Journal of Alloys and Compounds 2008; 461(1 - 2):166-172. http://dx.doi.org/10.1016/j.jallcom.2007.07.054
• 12. Varol T, Canakci A and Ozsahin S. Artificial neural network modeling to effect of reinforcement properties on the physical and mechanical properties of Al2024 - B4C composites produced by powder metallurgy. Composites. Part B: Engineering 2013; 54:224-233. http://dx.doi.org/10.1016/j.compositesb.2013.05.015
• 13. Fogagnolo JB, Velasco F, Robert MH and Torralba JM. Effect of mechanical alloying on the morphology, microstructure and properties of aluminium matrix composite powders. Materials Science and Engineering A 2003; 342(1-2):131-143. http://dx.doi.org/10.1016/S0921-5093(02)00246-0
• 14. Cook BA, Peters JS, Harringa JL and Russell AM. Enhanced wear resistance in AlMgB14 - TiB2 composites. Wear 2011; 271(5-6):640-646. http://dx.doi.org/10.1016/j.wear.2010.11.013
• 15. Kubota M, Kaneko J and Sugamata M. Properties of mechanically milled and spark plasma sintered Al - AlB2 and Al - MgB2 nano-composite materials. Materials Science and Engineering A 2008; 475(1 - 2):96-100. http://dx.doi.org/10.1016/j.msea.2007.02.130
• 16. Sivasankaran S, Sivaprasad K, Narayanasamy R and Iyer VK. Synthesis, structure and sinterability of 6061 AA100-x - x wt.% TiO2 composites prepared by high-energy ball milling. Journal of Alloys and Compounds 2010; 491(1-2):712-721. http://dx.doi.org/10.1016/j.jallcom.2009.11.051
• 17. Feng CF and Froyen L. Formation of Al3Ti and Al2O3 from an Al - TiO2 system for preparing in-situ aluminium matrix composites. Composites. Part A, Applied Science and Manufacturing 2000; 31(4):385-390. http://dx.doi.org/10.1016/S1359-835X(99)00041-X
• 18. Alamolhoda S, Heshmati-Manesh S and Ataie A. Mechano-thermal treatment of TiO2-Al powder mixture to prepare TiAl/Al2O3composite. Metals and Materials International 2011; 17(5):743-748. http://dx.doi.org/10.1007/s12540-011-1008-0
• 19. Gui M and Kang SB. Aluminum hybrid composite coatings containing SiC and graphite particles by plasma spraying. Materials Letters 2001; 51(5):396-401. http://dx.doi.org/10.1016/S0167-577X(01)00327-5
• 20. Akhlaghi F and Pelaseyyed SA. Characterization of aluminum/graphite particulate composites synthesized using a novel method termed in-situ powder metallurgy. Materials Science and Engineering A 2004; 385(1-2):258-266. http://dx.doi.org/10.1016/j.msea.2004.06.050
• 21. Altunpak Y, Ay M and Aslan S. Drilling of a hybrid Al/SiC/Gr metal matrix composites. International Journal of Advanced Manufacturing Technology 2012; 60(5-8):513-517. http://dx.doi.org/10.1007/s00170-011-3644-4
• 22. Zhang XQ, Peng YH, Li MQ, Wu SC and Ruan XY. Study of workability limits of porous materials under different upsetting conditions by compressible rigid plastic finite element method. Journal of Materials Engineering and Performance 2000; 9(2):164-169. http://dx.doi.org/10.1361/105994900770346114
• 23. Narayanasamy R, Ramesh T and Pandey KS. Workability studies on cold upsetting of Al - Al2O3 composite material. Materials & Design 2006; 27(7):566-575. http://dx.doi.org/10.1016/j.matdes.2004.12.005
• 24. Narayanasamy R, Anandakrishnan V and Pandey KS. Effect of geometric work-hardening and matrix work-hardening on workability and densification of aluminium - 3.5% alumina composite during cold upsetting. Materials & Design 2008; 29(8):1582-1599. http://dx.doi.org/10.1016/j.matdes.2007.11.006
• 25. Ramesh T, Prabhakar M and Narayanasamy R. Workability studies on Al - 5%SiC powder metallurgy composite during cold upsetting. International Journal of Advanced Manufacturing Technology 2009; 44(3-4):389-398. http://dx.doi.org/10.1007/s00170-008-1880-z
• 26. Narayanasamy R, Ramesh T and Pandey KS. Workability studies on cold upsetting of Al - Al2O3 composite material. Materials & Design 2006; 27(7):566-575. http://dx.doi.org/10.1016/j.matdes.2004.12.005
• 27. Narayanasamy R, Ramesh T and Pandey KS. Some aspects on workability of aluminium - iron powder metallurgy composite during cold upsetting. Materials Science and Engineering A 2005; 391(1-2):418-426. http://dx.doi.org/10.1016/j.msea.2004.09.018
• 28. Narayanasamy R, Senthilkumar V and Pandey KS. Some aspects of workability studies on P/M sintered high strength 4% Titanium carbide composite steel preforms during cold upsetting. International Journal of Mechanics and Materials in Design 2006; 3(1):39-57. http://dx.doi.org/10.1007/s10999-006-9012-0
• 29. Narayan S and Rajeshkannan A. Workability studies in forming of sintered Fe-0.35C powder metallurgy preform during cold upsetting. Journal of Iron and Steel Research International 2011; 18(12):71-78. http://dx.doi.org/10.1016/S1006-706X(12)60012-0
• 30. Narayanasamy R, Ramesh T and Prabhakar M. Effect of particle size of SiC in aluminium matrix on workability and strain hardening behaviour of P/M composite. Materials Science and Engineering A 2009; 504(1-2):13-23. http://dx.doi.org/10.1016/j.msea.2008.11.037
• 31. Randall M. Powder metallurgy science 2nd ed. New Jersey: Metal Powder Industries; 1984, p. 174.
• 32. Son HT, Kim TS, Suryanarayana C and Chun BS. Homogeneous dispersion of graphite in a 6061 aluminum alloy by ball milling. Materials Science and Engineering A 2003; 348(1-2):163-169. http://dx.doi.org/10.1016/S0921-5093(02)00749-9
• 33. Narayanasamy R, Anandakrishnan V and Pandey KS. Effect of carbon content on workability of powder metallurgy steels. Materials Science and Engineering A 2008; 494(1-2):337-342. http://dx.doi.org/10.1016/j.msea.2008.04.022
• 34. Wang Z, Song M, Sun C, Xiao D and He Y. Effect of extrusion and particle volume fraction on the mechanical properties of SiC reinforced Al - Cu alloy composites. Materials Science and Engineering A 2010; 527(24-25):6537-6542. http://dx.doi.org/10.1016/j.msea.2010.07.017
• 35. Zhang M, Yang X, Liu Y, Cao Z, Cheng L and Pei Y. Effect of graphite content on wear property of graphite/Al2O3/Mg-9Al-1Zn-0.8Ce composites. Transaction of Nonferrous Metals Society of China. 2010; 20(2):207-211. http://dx.doi.org/10.1016/S1003-6326(09)60122-9
• 36. Akhlaghi F and Zare-Bidaki A. Influence of graphite content on the dry sliding and oil impregnated sliding wear behavior of Al 2024 - graphite composites produced by in situ powder metallurgy method. Wear 2009; 266(1-2):37-45. http://dx.doi.org/10.1016/j.wear.2008.05.013

Publication Dates

• Publication in this collection
  10 Feb 2015
• Date of issue
  Dec 2014

History

• Received
  20 Dec 2013
• Accepted
  17 Nov 2014