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nanoindentation
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Development of fcc-Al nanoparticles during crystallization of amorphous Al–Ni alloys containing mischmetal: Microstructure and hardness evaluation [electronic resource]
, Article Materials Science and Engineering A ; Volume 604, 16 May 2014, Pages 92-97 ; Simchi, A ; Varahram, N ; Park, E. S ; Sharif University of Technology
Abstract
In the present work, fcc-Al nanoparticle development in Al90−xNi10MMx (MM: Ce mischmetal; x=2, 4) amorphous alloys was studied via non-isothermal differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, and nanoindentation test. Results showed that the crystallization of Al88Ni10MM2 alloy occurred by the precipitation of fcc-Al nanoparticles followed by the crystallization of Al11MM3 and Al3Ni phases. Transmission electron microscopy revealed that the aluminum precipitates had an average size of ~12 nm with a round morphology. Increasing the mischmetal content to 4 at% (Al86Ni10MM4 alloy) caused a three-stage crystallization process with a change in the size...
Effect of zirconia nanotube coating on the hydrophilicity and mechanochemical behavior of zirconium for biomedical applications
, Article Surfaces and Interfaces ; Volume 28 , 2022 ; 24680230 (ISSN) ; Sarraf, M ; Musharavati, F ; Jaber, F ; Wang, J. I ; Hosseini, H. R. M ; Bae, S ; Chowdhury, M ; So, H ; Sukiman, N. L ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Zirconium has attracted considerable attention in the biomedical field owing to its biocompatibility and desirable tribological and mechanical properties. In this study, we anodized pure zirconium in an ammonium fluoride and ethylene glycol electrolyte, which produced a coating of ZrO2 nanotubes (NTs). The ZrO2 coated samples were annealed at different temperatures, and the morphology and structure of the coated substrates were studied using XPS, SEM, TEM, EDS, and SAED. The micro/nanomechanical properties and corrosion resistance of the samples were evaluated. Wear tests performed on bare and coated substrates revealed that the coated samples annealed at 400 °C had a significantly lower...
Nanoindentation creep behavior of nanocomposite Sn-Ag-Cu solders
, Article Journal of Electronic Materials ; Volume 41, Issue 8 , 2012 , Pages 2057-2064 ; 03615235 (ISSN) ; Kokabi, A. H ; Miyashita, Y ; Mutoh, Y ; Ihara, I ; Guan Fatt, R. G ; Madaah Hosseini, H. R ; Sharif University of Technology
Abstract
High-density, ultrasmall-pitch electronic applications require miniaturized solder bumps with improved thermomechanical performance. In addition, novel techniques which are able to precisely characterize these solder bumps are needed. One approach to meeting both of these requirements is to make use of recently developed nanocomposite solders with enhanced creep resistance, and to characterize these solders using a nanoindentation technique. In the present study, the creep behavior of ceria-reinforced nanocomposite solder foils fabricated by the accumulative roll-bonding process was characterized using a depth-sensing nanoindentation technique. It was found that the creep resistance of the...
Study of Mechanical Properties of Polypropylene in Local and Global Scales: Effect of Crystalline Structure and Testing Conditions
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Asgari, Sirous (Supervisor) ; Naimi Jmal, Mohammad Reza (Co-Advisor)
Abstract
In this study, mechanical properties of neat isotactic polypropylene (iPP) were evaluated on local and global scales. Depth-sensing indentation with nanoscale resolution (nanoindentation) and traditional macromechanical tests were incorporated for this purpose at different temperatures and strain rates. Various morphologies and crystalline structures of iPP was obtained via changing processing conditions in melt state. A certain relation was found between the local and global mechanical properties, i. e. yield stress, modulus of elasticity and hardness. Moreover, developed yield models were evaluated on the local scale. The results showed that while crystal plasticity theory is not valid for...
Comparison of the mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile test: Molecular dynamics simulation
, Article Materials Research Express ; Volume 3, Issue 12 , 2016 ; 20531591 (ISSN) ; Vahedpour, M ; Sadrnezhaad, S. K ; Sharif University of Technology
Institute of Physics Publishing
2016
Abstract
Molecular dynamics simulation was used to study of mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile testing. A comparison has been made among mechanical properties measured and plastic deformation process at different copper thickness during nanoindnetation and tensile test of the samples. Embedded atom method potentials for describing of inter-Atomic interaction and Nose-Hoover thermostat and barostat are employed in the simulation at 400 K. The results showed that as the copper film thickness decreased, the maximum load and hardness values increased during nanoindetation. Saha and Nix model is used to describe reduced young's modulus behaviour of the bilayer system...
Effect of nano Al2O3 addition on mechanical properties and wear behavior of NiTi intermetallic
, Article Materials and Design ; Volume 51 , October , 2013 , Pages 375-382 ; 02613069 (ISSN) ; Ebadzadeh, T ; Vaezi, M. R ; Kim, H. S ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2013
Abstract
It has been found that the high wear resistance of NiTi alloy is mainly attributed to its pseudoelasticity which is only effective within a small temperature range. It is believed that pseudoelasticity becomes ineffective by applying high-load wear condition which yields plastic deformation and temperature increment during wear test. Therefore, the enhanced wear resistance can be obtained from the improvement of mechanical property of the alloy without much reduction of pseudoelasticity. In this study, a low weight percentage of hard Al2O3 nanoparticles were added to NiTi atomized powders. The resultant powder mixture was homogenized by ball milling and sintered in a vacuum furnace in order...
Finite Element Simulation of Nanoindentation and Nanoscratch Tests on Nanocoatings
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor) ; Fallah Rajabzadeh, Famida (Co-Advisor)
Abstract
Coatings are used in order to prevent wear, corrosion, thermal gradient reduction, surface strength improving and many other applications in industries. One of the common applications of coatings, is to prevent wear and surface abrasion. Hardness and friction coefficients are two parameters that determine the wear properties of a coating. Determining these parameters in very thin films is only possible by nanoindentation and nanoscratch tests. Surface hardness, young modulus and fracture toughness can be obtained using nanoindentation and friction coefficient is calculated from nanoscratch.
Finite element method is widely used for simulating the nanoindentation and nanoscratch...
Finite element method is widely used for simulating the nanoindentation and nanoscratch...
Investigation of Wear Properties of Nanocrystalline through Multiscale Modeling of Nanoindentation and Nanoscratch Test
, Ph.D. Dissertation Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor) ; Movahhedy, Mohammad Reza (Supervisor)
Abstract
Nanocrystalline materials have received increasing attention during the last decades. Polycrystalline structures with grain sizes less than 100 nm are referred as nanocrystalline (NC). Their mechanical properties differ significantly from polycrystalline structures. As an example, hardness and wear resistance of nanocrystalline structures are higher than those of polycrystalline structures. With the reduction of grain size, hardness increases based on the Hall–Petch relation. However, at the very small grain sizes the Hall–Petch relation breaks down and a fundamental shift takes place in hardening mechanism. Molecular dynamics (MD) simulation offers a powerful method for the investigation of...
Fabrication & Characterization of Al-Al3Ti-Al2O3 Nano-composites Based on the Thermal Degradation of Aluminium Titanate & Facile Study on the Correlation between Microstructure & Their Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Maddah Hosseini, Hamid Reza (Supervisor)
Abstract
In this study insitu Al-Al3Ti-Al2O3 nanocomposite has been fabricated based on thermal decomposition of tialite (Al2TiO5) precursor in aluminium matrix through powder metallurgy method. Also the effect of high energy mechanical milling and hot extrusion on this procedure has been investigated. In the first step nano-structured tialite were synthesized through citrate sol gel methods. Then, different volume fraction of tialte was mixed with aluminium by high energy vibratory milling. The results of X-ray differaction analysis, scanning electron microscopy and differential thermal analysis showed that mechanical milling can degrade stability of tialite and cause strain-induced decomposition,...
Developing a Molecular Dynamics Simulation Software for Modeling of Nano-Contact Processes (CEDRA Molecular Dynamics Software )
,
M.Sc. Thesis
Sharif University of Technology
;
Meghdari, Ali
(Supervisor)
;
Mahboobi, Hanif
(Supervisor)
Abstract
Molecular Dynamics as a powerful method in the field of Nano-simulation has been widely used in recent years. Different contact processes such as Nano-manipulation, AFM Imaging, and Nano-indentation can be simulated using this method. There have been numerous researches done on calculating techniques of simulation of different phenomena in Nano-technology. Specifically, friction and Nano-indentation which are parts of Nano-contact processes have been simulated by different investigators. However, on some other parts, e.g. Nano-manipulation and AFM Imaging, there are few studies done up to now. Thus, a simulation and computational software seems necessary in this field. The main goal of...
In-Situ Synthesis of Zif-8 Nanocomposite Coating on Carbon Steel and Investigating the Effect of Adding Mbt on Corrosion Behavior and Sic Nanoparticles on Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
Nowadays, metal-organic frameworks have received a lot of attention due to their properties and characteristics such as controllable structure, high specific surface area and the tunable porosity size and have found many applications. One group of metal-organic frameworks are zeolitic imidazolate frameworks which ZIF-8 is a member of this family, and many studies have been conducted on it. In the present study, ZIF-8 nanocomposite coating was applied to the plain carbon steel substrate by synthesis at room temperature and immersion method, and its corrosion behavior and mechanical properties were investigated. The effect of Mercaptobenzothiazole (MBT) inhibitor on corrosion behavior and...
The effects of thickness on magnetic properties of FeCuNbSiB sputtered thin films
, Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3521-3525 ; 10263098 (ISSN) ; Celegato, F ; Tiberto, P ; Castellero, A ; Baricco, M ; Hosseini, H. R. M ; Sharif University of Technology
Abstract
Thin films of Fe73.1Cu1Nb3.1Si14.7B8.2 alloy with 200, 500, and 800 nm thicknesses have been deposited by RF sputtering. Their magnetic properties have been characterized using Alternating Gradient Field Magnetometer (AGFM) and Vibrating Sample Magnetometer (VSM). The effects of residual stresses investigated by nanoindentation experiments were conducted on the as-deposited samples. It is observed that the coercivity of as-deposited films is inversely proportional to the thickness in relation with the residual stress induced during sputtering. © 2017 Sharif University of Technology. All rights reserved
Molecular dynamics simulation of plastic deformation and interfacial delamination of NiTi/Ag bilayer by cyclic-nanoindentation: Effects of crystallographic orientation of substrate
, Article Computational Materials Science ; Volume 168 , 2019 , Pages 229-245 ; 09270256 (ISSN) ; Sadrnezhaad, S. k ; Sharif University of Technology
Elsevier B.V
2019
Abstract
This paper presents a comparative study of plasticity and fracture behavior of the NiTi/Ag bilayer for the different crystallographic orientations of the substrate. Molecular dynamic (MD) simulation was used to determine the deformation mechanism, dislocation density, plastic energy dissipation and delamination of the NiTi/Ag bilayers near the interface, when NiTi aligned at (1 0 0), (1 1 1), (1 1 0), (3 2 1), (2 1 0) and (2 1 1) faces during the cyclic-nanoindentation test. The Griffith energy balance model was used to estimate the energy release associated with the delamination. The results of the simulation are suggested the dependence of deformation mechanism, energy release rate (Gin),...
Thermomechanical synthesis of hybrid in-situ Al-(Al3Ti+Al2O3) composites through nanoscale Al-Al2TiO5 reactive system
, Article Journal of Alloys and Compounds ; Volume 789 , 2019 , Pages 493-505 ; 09258388 (ISSN) ; Azarniya, A ; Madaah Hosseini, H. R ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this work, nanostructured aluminum titanate (Al2TiO5 or AT) was synthesized by the citrate sol gel method. Then, different volume fractions of this ceramic were blended with Al powder through different durations of the high-energy vibratory milling. The effect of mechanical milling on the thermal degradation of AT in exposure to Al and formation mechanism of in-situ Al2O3 and Al3Ti particles were explored in three conditions: (i) in the powder form; (ii) after annealing of green compact; and (iii) after hot extrusion. In the powder form, it was shown that the mechanical milling is able to significantly diminish the thermal stability of AT, so that the required temperature for the Al3Ti...
Nanoindentation of isotactic polypropylene: Correlations between hardness, yield stress, and modulus on the local and global scales
, Article Journal of Applied Polymer Science ; Volume 121, Issue 2 , February , 2011 , Pages 930-938 ; 00218995 (ISSN) ; Bagheri, R ; Asgari, S ; Sharif University of Technology
2011
Abstract
The correlations between the hardness, yield stress, and modulus of elasticity of isotactic polypropylene (iPP) were evaluated on the local and global scales. Nanoindentation and traditional macromechanical tests were incorporated for this purpose. Thus, local and global mechanical properties were measured at various temperatures and strain rates. A certain relation was found between the local and global mechanical properties. Moreover, Johnson's model (developed according to the expanding cavity model) was also evaluated at various temperatures and strain rates. The Johnson model was valid only for the yield stresses obtained by nanoindentation and compressive tests and also the elastic...
Effect of starting materials on the wear performance of NiTi-based composites
, Article Wear ; Volume 334-335 , July , 2015 , Pages 35-43 ; 00431648 (ISSN) ; Ebadzadeh, T ; Vaezi, M. R ; Yoon, E. Y ; Kim, Y. J ; Kang, J. Y ; Kim, H. S ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
NiTi alloys have exhibited significant potential as a matrix of wear resistant composites. In this study, in order to examine the effect of starting materials on the wear performance of NiTi-based composites, both elemental Ni/Ti and prealloyed NiTi powders were used to fabricate NiTi-6wt% nano-Al2 O3 composites using hot isostatic pressing (HIP). Nanoindentation and microhardness test results indicate that the composite samples produced from the elemental Ni/Ti powders exhibited higher hardness and lower pseudoelasticity properties than those of the samples fabricated from the prealloyed NiTi powders; this is attributed to the higher amount of...
Nanoindentation study of cementite size and temperature effects in nanocomposite pearlite: A molecular dynamics simulation
, Article Current Applied Physics ; Volume 16, Issue 9 , 2016 , Pages 1015-1025 ; 15671739 (ISSN) ; Karimi Taheri, A ; Ryu, S ; Kang, K ; Sharif University of Technology
Elsevier B.V
Abstract
We carry out molecular dynamics simulations of nanoindentation to investigate the effect of cementite size and temperature on the deformation behavior of nanocomposite pearlite composed of alternating ferrite and cementite layers. We find that, instead of the coherent transmission, dislocation propagates by forming a widespread plastic deformation in cementite layer. We also show that increasing temperature enhances the distribution of plastic strain in the ferrite layer, which reduces the stress acting on the cementite layer. Hence, thickening cementite layer or increasing temperature reduces the likelihood of dislocation propagation through the cementite layer. Our finding sheds a light on...
Loading drug on nanostructured Ti6Al4V-HA for implant applications
, Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 8 , 2018 , Pages 1159-1165 ; 1728144X (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Materials and Energy Research Center
2018
Abstract
Arrayed Ti6Al4V nanotubes (TNT) coated with hydroxyapatite (HA) were synthesized via electrochemical anodization method. Paracetamol was loaded onto TNT-HA electrode. Effects of anodization, nanotube formation and hydroxyapatite deposition on sorption and release of the drug were investigated. Saturation time of paracetamol on the anodized samples was 30% shorter than the hydroxyapatite-coated samples. Release behavior of the loaded drug was studied by (a) plunging the probe into phosphate buffered saline (PBS), (b) sampling the drug-loaded PBS at different times and (c) analyzing the solution via ultraviolet-visible (UV-vis) spectroscopy. Results showed that HA electrodes hold higher...
Experimental investigation and finite element simulation of the effect of surface roughness on nanoscratch testing
, Article Journal of Mechanical Science and Technology ; Volume 33, Issue 5 , 2019 , Pages 2331-2338 ; 1738494X (ISSN) ; Chamani, M ; Sharif University of Technology
Korean Society of Mechanical Engineers
2019
Abstract
Nanoscratch testing is a highly reliable method used to extract a variety of film properties. It is proven that many of the experimental factors can influence the obtained results, such as the probe tilt, the scratch depth, etc. On the other hand, the surface roughness of the samples is an important parameter in nanoscratch and other similar tests, including the nanoindentation test. Thus, the effect of surface roughness on both the nanoscratch experiments and finite element simulations has been investigated. By performing scratch tests on gold and copper films and carrying out the finite element (FE) simulations on the rough and smooth surfaces, the importance of surface morphology was...
Nanomechanical properties of TiO2 granular thin films
, Article ACS Applied Materials and Interfaces ; Volume 2, Issue 9 , 2010 , Pages 2629-2636 ; 19448244 (ISSN) ; Taghavinia, N ; Keshavarz Alamdari, E ; Volinsky, A.A ; Sharif University of Technology
2010
Abstract
Post-deposition annealing effects on nanomechanical properties of granular TiO2 films on soda-lime glass substrates were studied. In particular, the effects of Na diffusion on the films' mechanical properties were examined. TiO2 photocatalyst films, 330 nm thick, were prepared by dip-coating using a TiO2 sol, and were annealed between 100 °C and 500 °C. Film's morphology, physical and nanomechanical properties were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, differential thermo-gravimetric analysis, and nanoindentation. Contrary to expectations, the maximum film hardness was achieved for 300°C annealing, with a value of 0.69 ± 0.05 GPa....