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Effect of Post Cryorolling Treatments on Microstructural and Mechanical Behaviour of Ultrafine Grained Al-Mg-Si Alloy

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Journal of Materials Science & Technology 2014年第10期30卷 998-1005页

作者： P.Nageswara rao Dharmendra Singh r.jayaganthan Department of Metallurgical and Materials Engineering Indian Institute of Technology Roorkee

To investigate the effect of post cryorolling treatments on simultaneous enhancement in strength and ductility of ultrafine grained material （UFG）, AI 6061 alloy was subjected to cryorolling followed by warm rolling （Cr ＋ Wr） and compared with cryorolling followed by short annealing （Cr ＋ SA） at the same temperature. Transmission electron microscopy （TEM） was used to characterize the microstructural features of the processed material. The mechanical properties were investigated through Vickers hardness testing and tensile testing at room temperature. TEM, X-ray diffraction （XrD） and differential scanning calorimetry （DSC） were used to investigate the precipitation evolution in UFG material. results indicated that the alloy subjected to Cr ＋ Wr has shown improved mechanical properties （114 HV, ultimate tensile strength （UTS）： 350 MPa） as compared to that in the case of Cr ＋ SA （105 HV, UTS： 285 MPa）. The size of the precipitates observed in Cr ＋ Wr sample after peak ageing treatment is finer than that of peak aged Cr ＋ SA sample. The UTS of peak aged Cr ＋ Wr sample （UTS： 390 MPa） was found to be higher than that of peak aged Cr ＋ SA sample （UTS： 355 MPa）, without decrease in ductility.

关键词： Aluminium alloy Cryorolling Warm rolling Short annealing Mechanical properties Differential scanning calorimetry (DSC)

Microstructures and impact toughness behavior of Al 5083 alloy processed by cryorolling and afterwards annealing

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 759-769页

作者： Dharmendra Singh P.Nageswara rao r.jayaganthan Department of Metallurgical and Materials Engineering Indian Institute of Technology RoorkeeRoorkee-247667India

The influence of rolling at liquid nitrogen temperature and annealing on the microstructure and mechanical properties of Al 5083 alloy was studied in this paper. Cryorolled samples of Al 5083 show significant improvements in strength and hardness. The ultimate tensile strength increases up to 340 MPa and 390 MPa for the 30% and 50% cryorolled samples, respectively. The cryorolled samples, with 30% and 50% reduction, were subjected to Charpy impact testing at various temperatures from 190℃ to 100℃. It is observed that increasing the percentage of reduction of samples during cryorolling has significant effect on decreasing impact toughness at all temperatures by increasing yield strength and decreasing ductility. Annealing of samples after cryorolling shows remarkable increment in impact toughness through recovery and recrystallization. The average grain size of the 50% cryorolled sample （14 μm） after annealing at 350℃ for 1 h is found to be finer than that of the 30% cryorolled sample （25 μm）. The scanning electron microscopy （SEM） analysis of fractured surfaces shows a large-size dimpled morphology, resembling the ductile fracture mechanism in the starting material and fibrous structure with very fine dimples in cryorolled samples corresponding to the brittle fracture mechanism.

关键词： aluminum alloys cryorolling annealing microstructure impact toughness recovery recrystallization

Development and characterization of stainless steel fiber-based copper-free brake liner formulation:A positive solution for steel fiber replacement

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Friction 2020年第2期8卷 396-420页

作者： Vijay r D.Lenin SINGArAVELU r.jayaganthan Department of Production Engineering National Institute of TechnologyTiruchirappalli 620015Tamil NaduIndia Department of Engineering Design Indian Institute of Technology MadrasChennai 600036Tamil NaduIndia

This study deals with the development of drum brake liner for a multi-utility vehicle possessing a hydraulic brake system by varying 7 weight%of steel fiber and stainless steel fiber each,in friction composite *** developed friction composites were tested for physical,chemical,corrosion,mechanical,thermal properties,and tribological characteristics,under near-actual conditions using an inertia dynamometer as per industrial *** element analysis software(ANSYS)analysis was performed to show the thermal stress distribution of the developed friction composites at the maximum temperature rise due to heat generated during brake stops,and an extensive evaluation method was used to rank the *** study concludes that the brake factor of the stainless steel fiber-based friction composite produces stable performance in all conditions with a lower liner temperature rise of 340°C and lower thermal stress at 4.255294 ***,the steel fiber-based composites produced high performance at the beginning but deteriorated after a certain period due to higher levels of corrosion and a high temperature rise of 361°C resulting in a negative fade(-0.84%)and more thermal stress(5.619102 MPa).The primary plateau,secondary plateau,back transfer of drum wear debris,and the distribution of constituents on the worn surface of the developed composites in a resin matrix were identified and studied using a scanning electron microscope(SEM)equipped with energy-dispersive spectroscopy.

关键词： stainless steel fiber steel fiber brake liner friction composite

Structural,Wettability and Optical Investigation of Titanium Oxynitride Coatings:Effect of Various Sputtering Parameters

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Journal of Materials Science & Technology 2012年第6期28卷 512-523页

作者： Sushant K rawal Amit Kumar Chawla r.jayaganthan ramesh Chandra Centre of Nanotechnology Indian Institute of Technology RoorkeeRoorkee-247667India Nano Science Laboratory Institute Instrumentation CentreIndian Institute of Technology RoorkeeRoorkee-247667India Department of Mechanical Engineering Charotar University of Science and TechnologyChanga 388421India Department of Physics University of Petroleum and Energy StudiesDehradun-48007India Department of Metallurgical and Materials Engineering Indian Institute of Technology RoorkeeRoorkee-247667India

The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of titanium oxynitride films deposited on glass substrate by reactive magnetron sputtering. The X-ray diffraction graphs of titanium oxynitride films show evolution of various textures of TiO=N and TiN phases with increasing nitrogen flow rate and deposition time, but an increase in sputtering pressure from 4.0 to 8.0 Pa results in decline of various textures observed for TiO=Ny and TiN phases. The stress and strain calculated by sin2~ method are compressive, which decrease with increasing nitrogen flow rate from 55 to I00 sccm （standard cubic centimeter per minute） and increase with increasing deposition time from 80 to I40 min due to atomic penning effect and increasing thickness of the deposited films. The titanium oxynitride films have contact angle values above 90 deg., indicating that films are hydrophobic. The maximum contact angle of I09.1 deg. is observed at deposition time of 140 min. This water repellent property can add value to potential protective, wear and corrosion resistant application of titanium oxynitride films. The band gap decreases from 1.98 to 1.83 eV as nitrogen flow rate is increased from 55 to 100 sccm; it decreases from 1.93 to 1.79 eV as deposition time is increased from 80 to 140 min as more nitrogen incorporation results in higher negative potential of valence band N2p orbital. But it increases from 2.26 to 2.34 eV for titanium oxynitride films as sputtering pressure increases from 4.0 to 8.0 Pa.

关键词： Titanium oxynitride Sputtering parameters Contact angle Optical properties

Environmental Degradation Behavior of High-velocity Arc Sprayed FeCrBMnSi Alloy Coatings in a Coal Fired Boiler

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Acta Metallurgica Sinica(English Letters) 2013年第5期26卷 602-612页

作者： V.N.Shukla r.jayaganthan V.K.Tewari Department of Metallurgical and Materials Engineering Indian Institute of Technology Roorkee

FeCrBMnSi alloy coating on steel substrate（310S） was fabricated by a high-velocity arc spraying（HVAS） process. Degradation behavior of the coatings at temperatures of 700℃ and 900℃ in air and in the coal fired boiler at（700±10）℃ was studied. X-ray difraction（XrD） and scanning electron microscopy/energydisperse spectroscopy（SEM/EDS） were used to characterize the coating as well as to analyze the corrosion products for elucidating the corrosion *** exhibited dense and globular morphology and the splats were interconnected as evident from SEM analysis. The maximum microhardness of the coating was found to be 630–1060 HV. The FeCrBMnSi alloy coating has imparted necessary resistance to oxidation and showed good adherence to the 310S substrate during the exposures with no tendency for spallation of its oxide scale.

关键词： HVAS process Coating Microhardness Oxidation Erosion

Improved Fracture Toughness of Cryorolled and room Temperature rolled 6082 Al Alloys

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Acta Metallurgica Sinica(English Letters) 2014年第2期27卷 359-367页

作者： Vineet Kumar I.V.Singh B.K.Mishra r.jayaganthan Department of Mechanical and Industrial Engineering Indian Institute of Technology Department of Metallurgical and Materials Engineering Indian Institute of Technology

In the present work, 6082 Al alloy has been rolled to 40% and 70% thickness reductions at the cryogenic and room temperatures for the improvement in mechanical and fracture toughness properties. All cryorolled samples are subjected to aging at different temperatures, i.e., 140, 160, and 190 ℃ to improve the strength, ductility, and fracture toughness. The microstructures of the cryorolled （Cr） and room temperature rolled （rTr） alloy after 40% and 70% thickness reductions are characterized by FE-SEM to reveal the modes of failure. The results show that the starting bulk Al alloy specimen is fractured in total ductile manner, consisting of well-developed dimples over the entire surface. The mechanical properties and fracture toughness of the 70% Cr alloy are found better than 70% rTr alloy due to higher dislocations density and formation of sub-grain structures in the Cr alloy.

关键词： 6082 Al alloy rolling Mechanical properties Fracture toughness J-Integral Material characterization

Texture Evolution and Ultrafine Grain Formation in Cross-Cryo-rolled Zircaloy-2

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Acta Metallurgica Sinica(English Letters) 2015年第7期28卷 837-846页

作者： Sunkulp Goel r.jayaganthan I.V.Singh D.Srivastava G.K.Dey N.Saibaba Department of Metallurgical and Materials Engineering Centre of Nanotechnology Department of Mechanical and Industrial Engineering Materials Science Division Bhabha Atomic Research Center Nuclear Fuel Complex Limited

The texture and mechanical properties of cross-rolled zircaloy-2 at 77 and 300 K were *** at 77 K was performed to impart different thickness reductions of 25% and 50%,while at 300 K with 25%,50%,75% and 85% reductions to the *** analysis of deformed sample showed that near-basal orientation is not deformed completely after 50% rolling *** activation of prismatic silp,{1122} contraction twin and {1012} extension twin were evident from the deformed microstructure at 77 *** propensity for activation of basal slip〈a〉 at77 K was also *** deformation of the sample at 300 K occurs by prismatic,basal 〈a〉 and pyramidal 〈c＋a〉slips,which were predicted by pole *** annealing,the tensile strengths（735 and 710 MPa） are almost the same for 50% cryo-cross-rolled and room-temperature cross-rolled zircaloy-2 with almost 2.7% difference in their *** analysis of the deformed samples was made to estimate the stored strain energy and dislocation *** of deformed sample at 673 K for 30 min results in recrystallization,which leads to the formation of ultrafine grains.

关键词： Cross-rolling EBSD TEM Ultrafine grains Texture

Effect of deformation temperature on precipitation, microstructural evolution, mechanical and corrosion behavior of 6082 Al alloy

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Transactions of Nonferrous Metals Society of China 2017年第3期27卷 475-492页

作者： NikhilKUMAr r.jayaganthan Heinz-GünterBrOKMEIEr department of metallurgical and materials engineering¢re of nanotechnology indian institute of technology roorkeeRoorkee 247667India department of engineering design indian institute of technology madrasChennai 600036India institute of materials science and engineering clausthal university of technologyagricolastrasse 6d-38678 clausthal-zellerfeldgermany&helmholtz zentrum geesthachtMax Planck Straße 1D-21502 GeesthachtGermany

The influence of cryorolling(Cr),room temperature rolling(rTr)and post annealing on precipitation,microstructuralevolution(recovery,recrystallisation and grain growth),mechanical and corrosion behavior,was investigated in the present *** precipitation kinetics and microstructural morphology of Cr,rTr,and post annealed samples were investigated by differentialscanning calorimetry(DSC),transmission electron microscopy(TEM),and electron back scattered diffraction(EBSD)to elucidatethe observed mechanical *** annealing at200°C,UTS and hardness of Cr samples(345MPa and HV127)wereimproved as compared to rTr samples(320MPa and HV115).The increase in hardness and UTS of Cr samples after annealing at200°C was due to precipitation ofβ''from Al matrix,which imparted higher Zener drag effect as compared to rTr *** in corrosion and pitting potentials was observed for Cr samples(?1.321V and?700mV)as compared to rTrsamples(?1.335V and?710mV).In Cr samples,heavy dislocation density and dissolution of Mg4Al3Si4-precipitates in the Almatrix have improved corrosion resistance of the alloy through formation of protective passive layer and suppression of galvanic cell,respectively.

关键词： aluminum alloy cryorolling mechanical property corrosion potential precipitation

Mechanical properties and microstructural evolution of ultrafine grained zircaloy-4 processed through multiaxial forging at cryogenic temperature

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Transactions of Nonferrous Metals Society of China 2015年第7期25卷 2221-2229页

作者： D.FULOrIA S.GOEL r.jayaganthan D.SrIVASTAVA G.K.DEY N.SAIBABA Department of Metallurgical and Materials Engineering Centre of Nanotechnology ⅡT Roorkee Materials Science Division Bhabha Atomic Research Center Nuclear Fuel Complex Limited

The mechanical properties and microstructural evolution of zircaloy-4 subjected to cumulative strains of 1.48,2.96,4.44 and 5.91 through multiaxial forging（MAF） at cryogenic temperature（77 K） were *** mechanical properties of the MAF treated alloy were measured through universal tensile testing and Vickers hardness testing *** zircaloy-4 deformed up to a cumulative strain of 5.91 showed improvement in both ultimate tensile strength and hardness from 474 MPa to 717 MPa and from HV 190 to HV 238,respectively,as compared with the as-received ***,there was a noticeable decrement in ductility（from 18%to 3.5%） due to the low strain hardening ability of deformed *** improvement in strength and hardness of the deformed alloy is attributed to the grain size effect and higher dislocation density generated during multiaxial *** microstructural evolutions of deformed samples were characterized by optical microscopy and transmission electron microscopy（TEM）.The evolved microstructure at a cumulative strain of 5.91 obtained after MAF up to 12 cycles depicted the formation of ultrafine grains with an average size of 150-250 nm.

关键词： zircaloy-4 multiaxial forging cryogenic temperature ultrafine-grain microstructural evolution mechanical properties