Instrumented Vickers microindentation of alumina-based materials

The adequacy of instrumented Vickers depth-sensing microindentation to determine Young's modulus of alumina-based ceramics was analyzed. Monophase alumina materials and alumina + 10 vol% aluminium titanate composites, with different microstructures, were tested to determine the effect of microcracking. The load–depth penetration of the indenter curves together with the observation of the imprints by scanning electron microscopy were used to analyze the behavior of the materials. Maximum stiffness was determined from the derivatives of the load-depth curves during unloading. The areas of the imprints measured optically were more representative of the behavior of the materials than the areas calculated from depth-penetration measurements. The formation of microcracks affected the shape of the unloading portion of the curves. Significant differences between the values of Young's modulus determined for different materials and definite relationships between the microstructural parameters of the materials and the Young's modulus were found.

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Possible Artefacts in Measurement of Hardness and Elastic Modulus on Superhard Coatings and the Verification of the Correctness of the Data

MRS Proceedings ◽

10.1557/proc-750-y1.3 ◽

2002 ◽

Vol 750 ◽

Cited By ~ 4

Author(s):

S. Veprek ◽

S. Mukherjee ◽

P. Karvankova ◽

H.-D. Männling ◽

J. L. He ◽

...

Keyword(s):

Plastic Deformation ◽

Young’S Modulus ◽

Indentation Depth ◽

Brillouin Scattering ◽

Young's Modulus ◽

Linear Extrapolation ◽

Depth Sensing ◽

Vibrating Reed ◽

Superhard Coatings ◽

Scanning Electron

ABSTRACTMeasurements of the hardness and Young's modulus of superhard coatings (HV≥40 GPa) by means of automated load-depth-sensing indentation technique can be subject to a number of errors that are discussed and exemplified here. Only load-independent values of hardness for loads larger than 30–50 mN can be considered reliable when the technique of Doerner and Nix (linear extrapolation of the unloading curve) is used to determine the corrected indentation depth. The results are compared with values of Vickers hardness calculated from the contact area of the remaining plastic deformation which was measured by means of calibrated scanning electron microscope. The values of Young's modulus obtained from the indentation are close to the zero-pressure shear modulus of the coatings as measured by means of Vibrating Reed and surface Brillouin scattering techniques.

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Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

Materials ◽

10.3390/ma14133467 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3467

Author(s):

Anna Nocivin ◽

Doina Raducanu ◽

Bogdan Vasile ◽

Corneliu Trisca-Rusu ◽

Elisabeta Mirela Cojocaru ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Plastic Deformation ◽

Severe Plastic Deformation ◽

Young’S Modulus ◽

Young's Modulus ◽

Solution Treatment ◽

Young Modulus ◽

Orthopedic Implants ◽

Beta Titanium Alloy

The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of etot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.

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Glass-Alumina Functionally Graded Materials Produced by Plasma Spraying

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.333.227 ◽

2007 ◽

Vol 333 ◽

pp. 227-230

Author(s):

Valeria Cannillo ◽

Luca Lusvarghi ◽

Tiziano Manfredini ◽

M. Montorsi ◽

Cristina Siligardi ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Plasma Spraying ◽

Functionally Graded Materials ◽

Cross Sections ◽

Functionally Graded ◽

Depth Sensing ◽

Graded Materials ◽

Set Up ◽

Scanning Electron

The present work was focused on glass-alumina functionally graded materials. The samples, produced by plasma spraying, were built as multi-layered systems by depositing several layers of slightly different composition, since their alumina and glass content was progressively changed. After fabricating the graded materials, several, proper characterization techniques were set up to investigate the gradient in composition, microstructure and related performances. A particular attention was paid to the observation of the graded cross sections by scanning electron microscopy, which allowed to visualize directly the graded microstructural changes. The scanning electron microscopy (SEM) inspection was integrated with accurate mechanical measurements, such as systematic depth-sensing Vickers microindentation tests performed on the graded cross sections.

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Microprobe-type measurement of Young's modulus and Poisson coefficient by means of depth sensing indentation and acoustic microscopy

Surface and Coatings Technology ◽

10.1016/s0257-8972(01)01706-6 ◽

2002 ◽

Vol 154 (1) ◽

pp. 42-48 ◽

Cited By ~ 31

Author(s):

C. Comte ◽

J. von Stebut

Keyword(s):

Young’S Modulus ◽

Young's Modulus ◽

Acoustic Microscopy ◽

Depth Sensing ◽

Poisson Coefficient

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The Structure and the Mechanical Properties of a Newly Fabricated Cellulose-Nanofiber/Polyvinyl-Alcohol Composite

MRS Proceedings ◽

10.1557/opl.2014.141 ◽

2014 ◽

Vol 1621 ◽

pp. 149-154

Author(s):

Yukako Oishi ◽

Atsushi Hotta

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Cellulose Nanofibers ◽

Small Diameter ◽

Short Fiber ◽

Cellulose Nanofiber ◽

Process Conditions ◽

Aspect Ratios

ABSTRACTCellulose nanofibers (Cel-F) were extracted by a simple and harmless Star Burst (SB) method, which produced aqueous cellulose-nanofiber solution just by running original cellulose beads under a high pressure of water in the synthetic SB chamber. By optimizing the SB process conditions, the cellulose nanofibers with high aspect ratios and the small diameter of ∼23 nm were obtained, which was confirmed by transmission electron microscopy (TEM). From the structural analysis of the Cel-F/PVA composite by the scanning electron microscopy (SEM), it was found that the Cel-F were homogeneously dispersed in the PVA matrix. Considering the high molecular compatibility of the cellulose and PVA due to the hydrogen bonding, a good adhesive interface could be expected for the Cel-F and the PVA matrix. The influences of the morphological change in Cel-F on the mechanical properties of the composites were analysed. The Young’s modulus rapidly increased from 2.2 GPa to 2.9 GPa up to 40 SB treatments (represented by the unit Pass), whereas the Young’s modulus remained virtually constant above 40 Pass. Due to the uniform dispersibility of the Cel-F, the Young’s modulus of the 100 Pass composite at the concentration of 5 wt% increased up to 3.2 GPa. The experimental results corresponded well with the general theory of the composites with dispersed short-fiber fillers, which clearly indicated that the potential of the cellulose nanofibers as reinforcement materials for hydrophilic polymers was sufficiently confirmed.

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Improved Osseointegration of a TiNbSn Alloy with a Low Young’s Modulus Treated with Anodic Oxidation

Scientific Reports ◽

10.1038/s41598-019-50581-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Tomonori Kunii ◽

Yu Mori ◽

Hidetatsu Tanaka ◽

Atsushi Kogure ◽

Masayuki Kamimura ◽

...

Keyword(s):

Electron Microscopy ◽

Sulfuric Acid ◽

Young’S Modulus ◽

Anodic Oxidation ◽

Photoelectron Spectroscopy ◽

Young's Modulus ◽

Ti6al4v Alloy ◽

Apatite Formation ◽

X Ray ◽

Pull Out

Abstract Ti6Al4V alloy orthopedic implants are widely used as Ti6Al4V alloy is a biocompatible material and resistant to corrosion. However, Ti6Al4V alloy has higher Young’s modulus compared with human bone. The difference of elastic modulus between bone and titanium alloy may evoke clinical problems because of stress shielding. To resolve this, we previously developed a TiNbSn alloy offering low Young’s modulus and improved biocompatibility. In the present study, the effects of sulfuric acid anodic oxidation on the osseointegration of TiNbSn alloy were assessed. The apatite formation was evaluated with Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy analyses. The biocompatibility of TiNbSN alloy was evaluated in experimental animal models using pull-out tests and quantitative histological analyses. The results of the surface analyses indicated that sulfuric anodic oxidation induced abundant superficial apatite formation of the TiNbSn alloy disks and rods, with a 5.1-µm-thick oxide layer and submicron-sized pores. In vivo, treated rods showed increased mature lamellar bone formation and higher failure loads compared with untreated rods. Overall, our findings indicate that anodic oxidation with sulfuric acid may help to improve the biocompatibility of TiNbSn alloys for osseointegration.

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Young's modulus size effect of SCS nanobeam by tensile testing in electron microscopy

2009 IEEE Sensors ◽

10.1109/icsens.2009.5398190 ◽

2009 ◽

Cited By ~ 2

Author(s):

Q. H. Jin ◽

T. Li ◽

Y. L. Wang ◽

X. X. Li ◽

H. Yang ◽

...

Keyword(s):

Electron Microscopy ◽

Size Effect ◽

Young’S Modulus ◽

Tensile Testing ◽

Young's Modulus

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A systematic study of the validation of Oliver and Pharr’s method

Journal of Materials Research ◽

10.1557/jmr.2007.0428 ◽

2007 ◽

Vol 22 (12) ◽

pp. 3385-3396 ◽

Cited By ~ 8

Author(s):

Siqi Shu ◽

Jian Lu ◽

Dongfeng Li

Keyword(s):

Mechanical Properties ◽

Strain Hardening ◽

Young’S Modulus ◽

Basic Assumption ◽

Young's Modulus ◽

Strain Hardening Exponent ◽

The Finite Element Method ◽

Solid Materials ◽

Simulation Results ◽

Depth Curves

Oliver and Pharr’s method (O&P’s method) is an efficient and popular way of measuring the hardness and Young’s modulus of many classes of solid materials. However, there exists a range of errors between the real values and the calculated values when O&P’s method is applied to materials not included in the basic assumption proposed initially. In this article, the dimensional analysis theorem and the finite element method are applied to evaluate errors for high elastic (E/σY → 5) to full plastic (E/σY→ 1000) materials with different strain-hardening exponents from 0 to 0.5. A new method is proposed to correct errors obtained using O&P’s method. The numerical simulation results show that the errors obtained using O&P’s method, given in the form of charts, are mainly dependent on the ratio of the reduced Young’s modulus to the yield stress (i.e., Er/σY) and the strain-hardening exponent, n, for an indenter with a fixed included angle. The two mechanical properties, which can be extracted from the load–depth curves of two indenters with different included angles, are used to correct the errors in the hardness and Young’s modulus of the indented materials produced by O&P’s method.

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