NANOINDENTATION STUDY OF NANOCRYSTALLINE NICKEL

2005 ◽  
Vol 04 (02) ◽  
pp. 197-205 ◽  
Author(s):  
R. JAYAGANTHAN ◽  
K. MOHANKUMAR ◽  
A. A. O. TAY
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Grain Boundary ◽  
Modulus Of Elasticity ◽  
Loading Rate ◽  
Defect Density ◽  
Rate Sensitivity ◽  
Load Rate ◽  
Loading And Unloading ◽  
Force Displacement

The mechanical properties of nanocrystalline (Nc) Ni (electrodeposited, sintered, rolled) and microcrystalline (Mc) Ni were investigated by nanoindentation technique. Force-displacement curves generated during loading and unloading of the nanoindenter tip (Berkovich diamond tip) were used to determine the hardness and elastic properties of the Nc-nickel. The influence of loading rate on the hardness of electrodeposited Nc- Ni and microcrystalline (Mc) Ni were studied in the present work. The electrodeposited Nc-nickel exhibits higher hardness and elastic modulus when compared to sintered Nc-nickel. The higher modulus of elasticity is observed for the rolled Nc-nickel due to the increased defect density and less porosity in the samples. The higher modulus of elasticity is observed for Mc-nickel when compared to that of Nc-nickel (electrodeposited) with varying load rate. The strain rate sensitivity of Nc-nickel is due to the grain boundary affected zone.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

Influence of Annealing on the Microstructure and Mechanical Properties of Electrodeposited Nanocrystalline Nickel

2011 ◽  
Vol 683 ◽  
pp. 103-112 ◽  
Author(s):  
B. Yang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Elastic Modulus ◽  
Grain Boundary ◽  
Boundary Structure ◽  
Boundary State ◽  
Microstructure And Mechanical Properties ◽  
Grain Boundary Structure ◽  
Average Grain Size ◽  
Different Grain Size

The evolution of the microstructure and mechanical properties of electrodeposited nanocrystalline Ni with different annealing procedures was studied systematically. For the annealed specimens hardness decreases with increasing average grain size but the dependence changes at different grain size ranges. The specimens annealed at a low temperature show higher hardness compared to the as-deposited nanocrystalline Ni, despite an increased measured average grain size. In association with this hardening an increase in elastic modulus and a decrease in microstrain was observed after annealing. With increasing annealing temperature both the tensile strength and the fracture strain were observed to decrease, this is companied with a transition from ductile to brittle in the fracture surfaces. These results indicated that the mechanical behaviour of nanocrystalline Ni depends not only on the average grain size but also on the grain boundary structure. A change in the grain boundary state arising from annealing may be responsible for the observed increase in hardness and elastic modulus as well as the deterioration of tensile properties.

Production of mullite‒TiC‒с-BN‒с-ZrO2-materials by the method of plasma-spark sintering and their properties

2019 ◽  
pp. 23-29 ◽  
Author(s):  
A. V. Hmelov
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Elastic Modulus ◽  
Linear Correlation ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
Physicomechanical Properties ◽  
Intensive Development ◽  
Crystalline Microstructure

The effect of different с-BN and с-ZrO2 ratios on the phase composition, microstructure, relative density, open porosity, linear shrinkage, physicomechanical properties, and linear correlation of the elastic modulus and toughness of samples during plasma-spark sintering at pressing load 70 MPa in the range of 1200‒1600 °C is shown. The synthesized powders of TiC, c-BN and c-ZrO2, sintered at 1400 °C by the plasma-spark method, are characterized by intense crystallization of the phases. Sintered samples with different ratios of c-BN and c-ZrO2 show the intensive development of mullite and TiC. An increase in the c-BN / c-ZrO2 ratio promotes an active increase in c-BN and a less intensive increase in с-ZrO2 in the range of 1200‒1600 °C, and it causes the formation of a less uniform and densely sintered crystalline microstructure with a large number of pores at 1500 °C. This sample has lower values of physical and mechanical properties and a lower linear correlation of the modulus of elasticity and toughness in the range of 1200‒1600 °C and lower crack resistance at 1500 °C. Ill. 9. Ref. 13. Tab. 1.

Mechanical properties of porous structure 3D printed with Vero White photosensitive resin

2019 ◽  
Vol 26 (3) ◽  
pp. 539-548
Author(s):  
Tianbiao Yu ◽  
Yu Zhao ◽  
Xiaoxi Bi ◽  
Boxue Song ◽  
Ying Chen
Keyword(s):  
Mechanical Properties ◽  
Regression Analysis ◽  
Elastic Modulus ◽  
Porous Structure ◽  
Cross Section ◽  
Modulus Of Elasticity ◽  
Maximum Stress ◽  
Honeycomb Structure ◽  
Content Type ◽  
Photosensitive Resin

Purpose The purpose of this paper is to study the influence of the porous structure on the maximum stress and modulus of elasticity of the specimens which are fabricated by rapid prototypes. According to the experimental results, modify the theoretical formula of elastic modulus. Design/methodology/approach The Objet Eden 250 was used to prepare the Vero White photosensitive resin samples with different porosity (ranges from 25 to 65 per cent) and different pore structures. The mechanical properties of different samples were numerically simulated and the formulas of the modulus of elasticity were established. Through the compression test, the performance of the specimen is compared and analyzed, and the theoretical elastic modulus formula is optimized. Findings With the increase of porosity, the maximum stress of honeycomb structure specimens decreases. The maximum stress of the honeycomb structure specimen with circular pore shape is higher than the hexagon cross-section while the hexahedron and octahedron structure are the arms (wall thickness between pores) with a square cross-section. The error comparison between the modulus of elasticity before and after the structure models regression analysis shows that after the regression analysis, the error of theoretical value and the actual value is between 0 and 14 per cent which is lower than the value before the regression analysis which was between 5 and 27 per cent. Originality/value The paper obtains rules of the influence of different porous structures which were fabricated by the Vero White photosensitive resin material on mechanical properties and higher prediction accuracy formula of elastic modulus. The conclusions provide a theoretical basis for Northeastern University, China, to reduce mass and mechanical properties prediction of load-bearing parts.

scholarly journals Investigation on the preparation and mechanical properties of porous Cu35Ni15Cr alloy for a molten carbonate fuel cell

2015 ◽  
Vol 33 (4) ◽  
pp. 887-893
Author(s):  
Cong Li ◽  
Jian Chen ◽  
Wei Li ◽  
Yanjie Ren ◽  
Jianjun He
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Ball Milling ◽  
Deformation Temperature ◽  
Loading Rate ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Β Phase ◽  
Steady Level

AbstractThe preparation process of porous Cu35Ni15Cr alloy was studied in this paper. The effect of ball milling time and sintering temperature on the porosity of Cu35Ni15Cr alloy was identified. It was found that 18 h ball milling and 950 °C sintering are the most promising parameters for the preparation of porous Cu35Ni15Cr alloy. The products have a ~62 % porosity. The alloy consists of an α phase and β phase. The influence of deformation temperature and loading rate on the mechanical properties of Cu35Ni15Cr alloys was investigated. The results show that with decreasing deformation temperature, the yield strength and elastic modulus of the porous alloy increase. With the increase of loading rate, the yield strength of these alloys shows an increasing trend, but the elastic modulus is on a steady level.

The Study of Mechanical Properties of Structural Lightweight Concrete

2010 ◽  
Vol 97-101 ◽  
pp. 1620-1623 ◽  
Author(s):  
Hong Zhi Cui ◽  
Feng Xing
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Bond Strength ◽  
Modulus Of Elasticity ◽  
Lightweight Concrete ◽  
Experimental Studies ◽  
Lightweight Aggregate ◽  
Experimental Results ◽  
The Relationship

Many investigations have been conducted on compressive strength of lightweight aggregate concretes (LWAC), but there are few experimental studies on the relationship between compressive strength, bond strength and elastic modulus of LWAC. In this paper, the specimens of twenty kinds of LWACs with different mix proportions were made. Properties of compressive strength, bond strength and modulus of elasticity of the LWACs were tested. Based on the testing resulting, equations for relationship between bond strength and compressive strength of the LWAC were established. For LWAC modulus of elasticity, the experimental results of this study can fit well with predicted equation of ACI 318

scholarly journals Enhanced Mechanical Properties of Metallic Glass Thin Films via Modification of Structural Heterogeneity

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 999
Author(s):  
Xindi Ma ◽  
Kang Sun ◽  
Peiyou Li ◽  
Nizhen Zhang ◽  
Qing Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Metallic Glass ◽  
Substrate Temperature ◽  
Rate Sensitivity ◽  
Structural Heterogeneity ◽  
Higher Temperature ◽  
Spectrum Intensity ◽  
Substrate Temperatures

The structure of Cu50Zr50 and Co56Ta35B9 metallic glass thin films (MGTF) was effectively tailored via various applied substrate temperatures by means of the magnetron sputtering technology. Obviously enhanced hardness and elastic modulus are achieved by different compositional MGTFs by increasing the substrate temperature. Compared with the CuZr MGTFs, the CoTaB MGTF deposited at 473 K displays the smaller strain-rate sensitivity exponent, m, and a weaker spectrum intensity based on the nanoindentation creep test, suggesting its better creep resistance. In addition, the STZ volume of the CoTaB MGTF significantly decreases after depositing at higher temperature. According to the nano-scratch analysis, the CoTaB MGTF at the substrate temperatures of 473 K performs the shallower scratch width and the larger H3/E2 value, indicating its better tribological property.

scholarly journals Investigation of Mechanical Properties and Plastic Deformation Behavior of (Ti45Cu40Zr10Ni5)100−xAlxMetallic Glasses by Nanoindentation

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Lanping Huang ◽  
Xuzhe Hu ◽  
TaoTao Guo ◽  
Song Li
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Elastic Modulus ◽  
Amorphous Alloy ◽  
Deformation Behavior ◽  
Alloy Composition ◽  
Loading Rate ◽  
Al Content ◽  
Plastic Deformation Behavior ◽  
Al Addition

The effect of Al addition on mechanical properties and plastic deformation behavior of (Ti45Cu40Zr10Ni5)100−xAlx(x= 0, 2, 4, 6 and 8) amorphous alloy ribbons have been investigated by nanoindentation. The hardness and elastic modulus do not simply increase with the increase of Al content. The alloy with 8 at.% Al exhibits the highest hardness and elastic modulus. The serrations or pop-in events are strongly dependent on the loading rate and alloy composition.

scholarly journals Study on Mechanical Properties and Damage Evolution of High-Porosity Concrete under Cyclic Loading and Unloading

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Dong Zhang ◽  
Ai-hong Lu ◽  
Xia Wang ◽  
Yu Xia ◽  
Si-yu Gong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cyclic Loading ◽  
Damage Evolution ◽  
Stress Amplitude ◽  
High Porosity ◽  
Peak Strain ◽  
Cycle Number ◽  
Cyclic Loading And Unloading ◽  
Loading And Unloading

Understanding the mechanical properties and energy response of high-porosity concrete under the cyclic loading and unloading is the foundation of road construction in sponge city. In this study, the concrete with the porosity of 15% was taken as the research object, and the cyclic loading and unloading tests on the high-porosity concrete were performed under the stress amplitude of 25 MPa, 30 MPa, and 35 MPa in the elastic stage. The effects of stress amplitude and cycle number on the mechanical characteristics and damage evolution law of concrete were obtained. The experimental results show the following. (1) With the increase of cycle number, the loading and unloading elastic modulus of concrete under different stress amplitudes first increases and then decreases; the greater the stress amplitude, the faster the growth and deceleration of the loading and unloading elastic modulus. (2) With the increase of the cycle number, the peak strain and residual plastic deformation increase. (3) The greater the stress amplitude, the higher the damage of concrete; with the increasing number of cyclic loading and unloading, the damage of concrete is enhanced gradually. When the damage variable value is 1, the relationship between the cycle number and the initial stress amplitude satisfies a negative exponential function.

scholarly journals Evaluation the Effects of Some Relevant Parameters on Elastic Modulus of Pumpkin Seed and Its Kernel

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Hossein Abbaspour-Fard ◽  
Rasool Khodabakhshian ◽  
Bagher Emadi ◽  
Hasan Sadrnia
Keyword(s):  
Elastic Modulus ◽  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Loading Rate ◽  
Pumpkin Seed ◽  
Compression Loading ◽  
Average Modulus

The elastic modulus of two varieties of Iranian pumpkin seed and its kernel (namely, Zaria and Gaboor) were evaluated as a function of size (large, medium, and small), loading rate (2, 5, 8, and 10 mm/min), and moisture content (4, 7.8, 14, and 20% d.b) under quasistatic compression loading. The results showed that elastic modulus of pumpkin seed and its kernel decreased with increasing moisture content and also increasing loading rate, for the varieties under study. The average modulus of elasticity of pumpkin seed from 68.86 to 46.65 Mpa and from 97.14 to 74.93 Mpa was obtained for moisture levels ranging from 4 to 20%, for Zaria and Gaboor varieties, respectively. The elastic modulus of pumpkin seed decreased from 73.55 to 43.04 Mpa and from 101.83 to 71.32 Mpa with increasing loading rate from 2 to 10 mm/min for Zaria and Gaboor varieties, respectively.

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