scholarly journals Influence of Tungsten Alloying Additions on the Mechanical Properties and Texture of Tantalum

1993 ◽  
Vol 322 ◽  
Author(s):  
G.T. Gray ◽  
S.R. Bingert ◽  
S.I. Wright ◽  
S.R. Chen
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
Mechanical Response ◽  
Loading Path ◽  
Systematic Effect ◽  
Alloying Additions ◽  
Strain Behavior ◽  
Bcc Metals ◽  
Work Hardening Rate ◽  
Tension And Compression

AbstractTantalum, like all bcc metals, exhibits deformation behavior which is substantially influenced by alloying, temperature, and strain rate. Recently, the mechanical response, in particular the highstrain- rate response, of tantalum and tantalum alloys has received increased interest for ballistic applications. In this paper, recent results on the influence of tungsten alloying additions on the mechanical response and starting crystallographic texture of tantalum-tungsten alloys are presented. The stress-strain behavior of three tantalum alloys containing 2.5, 5, and 10 wt.% W has been investigated as a function of loading path, tension and compression, and strain rate, 10−3 to 8000 s−l The yield strength and work-hardening rate were found to increase with increasing tungsten alloying content compared to unalloyed-Ta. Based on measurements of the surface and centerline textures of the Ta-W alloys, no systematic effect of tungsten content on texture was documented. However, due to variations in mechanical behavior between through-thickness and in-plane properties the need for complete through-thickness texture measurements is indicated.

scholarly journals Compressive Mechanical Properties of Porcine Brain: Experimentation and Modeling of the Tissue Hydration Effects

2019 ◽  
Vol 6 (2) ◽  
pp. 40 ◽  
Author(s):  
Raj K. Prabhu ◽  
Mark T. Begonia ◽  
Wilburn R. Whittington ◽  
Michael A. Murphy ◽  
Yuxiong Mao ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Water Content ◽  
Mechanical Response ◽  
High Strain ◽  
Peak Stress ◽  
Human Head ◽  
Element Analysis ◽  
Porcine Brain ◽  
Strain Behavior

Designing protective systems for the human head—and, hence, the brain—requires understanding the brain’s microstructural response to mechanical insults. We present the behavior of wet and dry porcine brain undergoing quasi-static and high strain rate mechanical deformations to unravel the effect of hydration on the brain’s biomechanics. Here, native ‘wet’ brain samples contained ~80% (mass/mass) water content and ‘dry’ brain samples contained ~0% (mass/mass) water content. First, the wet brain incurred a large initial peak stress that was not exhibited by the dry brain. Second, stress levels for the dry brain were greater than the wet brain. Third, the dry brain stress–strain behavior was characteristic of ductile materials with a yield point and work hardening; however, the wet brain showed a typical concave inflection that is often manifested by polymers. Finally, finite element analysis (FEA) of the brain’s high strain rate response for samples with various proportions of water and dry brain showed that water played a major role in the initial hardening trend. Therefore, hydration level plays a key role in brain tissue micromechanics, and the incorporation of this hydration effect on the brain’s mechanical response in simulated injury scenarios or virtual human-centric protective headgear design is essential.

The Rate (Time)-Dependent Mechanical Behavior of the PMR-15 Thermoset Polymer at 316°C: Experiments and Modeling

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
M. B. Ruggles-Wrenn ◽  
O. Ozmen
Keyword(s):  
Experimental Data ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Inelastic Deformation ◽  
Rate Sensitivity ◽  
Experimental Program ◽  
Strain Rates ◽  
Neat Resin ◽  
Strain Behavior ◽  
Thermoset Polymer

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 316°C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain-controlled loading were examined. Positive, nonlinear strain rate sensitivity is observed in monotonic loading. The material exhibits nonlinear, “curved” stress-strain behavior during unloading at all strain rates. The recovery of strain at zero stress is strongly influenced by the prior strain rate. The prior strain rate also has a profound effect on relaxation behavior. Likewise, creep response is significantly influenced by the prior strain rate. The experimental data are modeled with the viscoplasticity theory based on overstress (VBO). The comparison with experimental data demonstrates that the VBO successfully predicts the inelastic deformation behavior of the PMR-15 polymer under various test histories at 316°C.

scholarly journals Strain Rate Sensitive Deformation Behavior under Tension and Compression of Al 0.3 CrFeCoNiMo 0.2

2021 ◽  
Author(s):  
Lisa-Marie Rymer ◽  
Philipp Frint ◽  
Thomas Lindner ◽  
Georg Gebel ◽  
Martin Löbel ◽  
...  
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
Tension And Compression

Effects of Deviation from Stoichiometry on Deformation Behavior of Hard-Oriented NiAl Single Crystals

1998 ◽  
Vol 552 ◽  
Author(s):  
R. Srinivasan ◽  
M. F. Savage ◽  
R. D. Noebe ◽  
M. J. Mills
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
Deformation Behavior ◽  
Mechanical Response ◽  
Slip Systems ◽  
Alloying Additions ◽  
Strain And Strain Rate ◽  
Deviation From Stoichiometry ◽  
Slip Transition ◽  
Active Slip

ABSTRACTNi-44A1, Ni-50Al and NiAl-0.3 at.% Hf single crystals have been studied in compression to understand the effects that alloying additions and deviation from stoichiometry can have on the mechanical response of NiAl-based single crystals. While all three single crystals deform through a<111> slip at lower temperatures, the active slip systems differ at higher temperatures. Climb of a<010> dislocations contributes to deformation in Ni-50AI single crystals beyond the slip transition temperature, while Ni-44Al and NiAl-0.3Hf crystals deform through a<101> glide. But several microstructural differences have been observed in the mode of deformation between Ni-44Al and NiAl-0.3Hf crystals. In addition, significant strengthening is exhibited in the Hf-doped crystals at higher temperatures. The post-deformation microstructure is also observed to be sensitive to both strain and strain rate. A possible explanation is offered for some of the observed differences in deformation behavior between the three alloys.

Effects of Temperature and Strain Rate on Tensile Deformation Behavior of 9Cr-0.5Mo-1.8W-VNb Ferritic Heat-Resistant Steel

2017 ◽  
Vol 36 (9) ◽  
pp. 913-920 ◽  
Author(s):  
Xiaofeng Guo ◽  
Xiaoxiang Weng ◽  
Yong Jiang ◽  
Jianming Gong
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Work Hardening ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Tensile Deformation Behavior ◽  
Average Work ◽  
Work Hardening Rate ◽  
Effects Of Temperature ◽  
Strength And Ductility

AbstractA series of uniaxial tensile tests were carried out at different strain rate and different temperatures to investigate the effects of temperature and strain rate on tensile deformation behavior of P92 steel. In the temperature range of 30–700 °C, the variations of flow stress, average work-hardening rate, tensile strength and ductility with temperature all show three temperature regimes. At intermediate temperature, the material exhibited the serrated flow behavior, the peak in flow stress, the maximum in average work-hardening rate, and the abnormal variations in tensile strength and ductility indicates the occurrence of DSA, whereas the sharp decrease in flow stress, average work-hardening rate as well as strength values, and the remarkable increase in ductility values with increasing temperature from 450 to 700 °C imply that dynamic recovery plays a dominant role in this regime. Additionally, for the temperature ranging from 550 to 650 °C, a significant decrease in flow stress values is observed with decreasing in strain rate. This phenomenon suggests the strain rate has a strong influence on flow stress. Based on the experimental results above, an Arrhenius-type constitutive equation is proposed to predict the flow stress.

Compressive Mechanical Property Analysis of Eva Foam: Its Buffering Effects at Different Impact Velocities

2016 ◽  
Vol 33 (4) ◽  
pp. 435-441
Author(s):  
D.-S. Liu ◽  
Z.-H. Chen ◽  
C.-Y. Tsai ◽  
R.-J. Ye ◽  
K.-T. Yu
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Mechanical Response ◽  
Numerical Models ◽  
Element Model ◽  
Strain Rates ◽  
Material Parameter Identification ◽  
Strain Rate Effects ◽  
Static Compression ◽  
Strain Behavior

AbstractEVA foams, like all other polymers, also exhibit strain-rate effects and hysteresis. However, currently available approaches for predicting the mechanical response of polymeric foam subjected to an arbitrarily imposed loading history and strain-rate effect are highly limited. Especially, the strain rates in the intermediate rate domain (between 100and 102s–1) are extremely difficult to study. The use of data generated through the drop tower technique for implementation in constitutive equations or numerical models has not been considered in past studies. In this study, an experiment including a quasi-static compression test and drop impact tests with a high speed camera was conducted. An inverse analysis technique combined with a finite element model for material parameter identification was developed to determine the stress–strain behavior of foam at different specific strain rates. It was used in this study to simulate multiple loading and unloading cycles on foam specimens, and the results were compared with experimental measurements.

scholarly journals Temperature and strain rate dependent mechanical response of METCO 601 aluminium-polyester abradable seal coating

2018 ◽  
Vol 183 ◽  
pp. 04012
Author(s):  
Antonio Pellegrino ◽  
Maria Jesus Perez-Martin ◽  
Kalin Dragnevski ◽  
Giuseppe Zumpano ◽  
Nik Petrinic
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
Compressor Blades ◽  
Rate Dependent ◽  
Dynamic Experiments ◽  
Different Temperatures ◽  
Tension And Compression ◽  
Abradable Coatings ◽  
Sacrificial Materials ◽  
Tension Compression Asymmetry

Abradable coatings are utilised as sacrificial materials in low-pressure compressor casings, and in intermediate and high pressure compressors and seals. The adoption of abradable coatings allows for the clearance between compressor blades and casing to be minimised, increasing the overall efficiency of the engine. Quasi-static and dynamic experiments at different temperatures are conducted to characterise the mechanical response of a thermally-sprayed abradable seal coating. The material is composed of an aluminium continuum matrix and fairly well-dispersed polyester particles. Stress versus strain histories are measured in uniaxial tension and compression at strain rates ranging from 10-3 to 102 s-1, via non-standard experimental techniques. The material displays sensitivity to the strain rate and to the imposed temperature. The mechanical behaviour is brittle in tension while it exhibits higher strains to failure in compression. The material is characterised by a pronounced tension/compression asymmetry.

The Effects of Rolling and Annealing on the High Speed Impact Deformation Behavior of Mg-3%Li-1%Ce Alloy

2011 ◽  
Vol 415-417 ◽  
pp. 1090-1095
Author(s):  
Teng Liu ◽  
Gui Ying Sha ◽  
He Nan Wang ◽  
Xiao Lei Wang ◽  
Yu Hong Zhu
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
High Speed ◽  
Static Recrystallization ◽  
Strain Rate Range ◽  
Softening Effect ◽  
Strain Behavior ◽  
High Speed Impact ◽  
Impact Deformation ◽  
The Impact

In this paper, the effects of rolling and annealing on the high speed impact deformation behavior of the Mg-3%Li-1%Ce alloy were investigated by using the Hopkinson compressive bar. The results showed that the microstructures of the as-rolled alloy consisted mainly of deformed grains, with some secondary Mg12Ce particles in grain interior or on grain boundary. After annealing at 350 °C for one hour, static recrystallization happened and grains were significantly refined. For the annealed alloy, the impact stress-strain behavior is non-sensitive to strain rate in the strain rate range of 1000~1750 s-1. Under the strain rate of 2250 s-1, the dynamic behavior demonstrated negative strain rate effect. The occurrence of cracking was supposed to be the main reason for the strain rate softening effect.

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