Micromechanical Study of the Forged Ti-1023 Titanium Alloy by Micro-Indentation

2018 ◽  
Vol 765 ◽  
pp. 160-165
Author(s):  
Jiang Li ◽  
Fu Guo Li ◽  
Xin Kai Ma ◽  
Ming Jie Zhang ◽  
Zhan Wei Yuan
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Titanium Alloy ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strain Hardening Exponent ◽  
Instrumental Approach ◽  
Initial Yield Stress ◽  
Non Destructive ◽  
Micro Indentation

In order to study the micromechanical behaviour of the forged Ti-1023 titanium alloy, micro-indentation experiments of the forged Ti-1023 titanium alloy were performed with various maximum indentation loads from 500 mN to 4000 mN and various loading speeds from 5.06 mN/s to 51.85 mN/s. Using the experimental data, the non-destructive instrumental approach was applied to indicate the mechanical properties just like the Young’s modulusE, microhardnessH, initial yield stressσyand strain hardening exponentnusing theP-hcurves from the tests. The result showed that the value of the indentation Young’s modulus basically remain unchanged in the range from 110 GPa to 150 GPa andHdecreased with the increase of the load, the micro-indentaion plasticity constitutive equations were obtained by using Hookean elastic and power-law plastic stress-strain equations.

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

2007 ◽  
Vol 22 (12) ◽  
pp. 3385-3396 ◽  
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.

Determination of Young’s Modulus and Poisson’s Ratio of Coatings With Non-Destructive Indentation

2005 ◽  
Author(s):  
S. Jordan Liu ◽  
Q. Jane Wang
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Spherical Indentation ◽  
Engineering Practice ◽  
Substrate Effect ◽  
Non Destructive

Coatings are now extensively used in engineering practice to modify the surfaces of mechanical components for enhanced load-bearing ability, lubricity, and service endurance. Designing thin-film coatings to meet particular engineering needs requires the knowledge of accurate mechanical properties of the coatings. Young’s modulus and Poisson’s ratio are two basic mechanical properties of materials, which should be conveniently measured. However, the measurement of Young’s modulus of a thin film is hindered by the inevitable substrate effect when the conventional methods for a bulk material are used to obtain so called “reduced modulus”. This paper presents a direct and non-destructive method for the measurement of Young’s modulus and Poisson’s ratio of a thin-film coating and its substrate, based on the extended-Hertz theory developed for coated bodies in contact. The theory is used to analyze load-displacement data from a spherical indentation in the elastic range, where the substrate effect is intrinsically modeled. Two sets of validation experiments are shown for coatings of a few microns thick. This new method does not need any assumption on pressure distribution and Poisson’s ratio and can be easily incorporated into current indentation analysis systems.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

scholarly journals First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Group Vi ◽  
Group V ◽  
Β Phase ◽  
Ti Alloys ◽  
Ω Phase ◽  
Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

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

Materials ◽  
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.

scholarly journals Phase Formation, Microstructure and Mechanical Properties of Mg67Ag33 as Potential Biomaterial

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 461
Author(s):  
Konrad Kosiba ◽  
Konda Gokuldoss Prashanth ◽  
Sergio Scudino
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Equilibrium Phase ◽  
Antibacterial Properties ◽  
Equilibrium Phase Diagram ◽  
Compressive Yield Strength ◽  
X Ray ◽  
Fine Grained ◽  
Equilibrium Phases

The phase and microstructure formation as well as mechanical properties of the rapidly solidified Mg67Ag33 (at. %) alloy were investigated. Owing to kinetic constraints effective during rapid cooling, the formation of equilibrium phases is suppressed. Instead, the microstructure is mainly composed of oversaturated hexagonal closest packed Mg-based dendrites surrounded by a mixture of phases, as probed by X-ray diffraction, electron microscopy and energy dispersive X-ray spectroscopy. A possible non-equilibrium phase diagram is suggested. Mainly because of the fine-grained dendritic and interdendritic microstructure, the material shows appreciable mechanical properties, such as a compressive yield strength and Young’s modulus of 245 ± 5 MPa and 63 ± 2 GPa, respectively. Due to this low Young’s modulus, the Mg67Ag33 alloy has potential for usage as biomaterial and challenges ahead, such as biomechanical compatibility, biodegradability and antibacterial properties are outlined.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

Effect of Castor Oil Impregnation on the Physical and Mechanical Properties of Bacterial Cellulose

2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Scanning Electron Micrographs ◽  
Elongation At Break ◽  
Acetone Water

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.

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