The Effect of Strain Rate on the Mechanical Properties of Single Crystal NiAl

1990 ◽  
Vol 213 ◽  
Author(s):  
D.F. Lahrman ◽  
R.D. Field ◽  
R. Darolia
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Single Crystal ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Deformation Mechanisms ◽  
Strain Rates ◽  
Test Results ◽  
Work Hardening Rate ◽  
Crystallographic Orientations

ABSTRACTIn this study, the strain rate sensitivity of single crystal NiAl has been investigated by performing tensile tests as a function of temperature and two strain rates. Three crystallographic orientations, [100], [110], and [111] were studied. The tensile test results investigated include yield strength, work hardening rate and plastic strain to failure. The data are discussed in terms of deformation mechanisms in NiAl.

Dynamic Strain Aging in the Fe-Mn-Cu-C TWIP Steels

2013 ◽  
Vol 668 ◽  
pp. 861-864 ◽  
Author(s):  
Hai Jun Liu ◽  
Ding Yi Zhu ◽  
Xian Peng ◽  
Zhen Ming Hu ◽  
Ming Jie Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Work Hardening Rate ◽  
Twip Steels ◽  
High Work

Strain rate jump tests were performed on the Fe-Mn-Cu-C TWIP Steels to determine the strain rate sensitivity, and serrated plastic flow was observed in the stress-strain curves during tensile tests at different constant strain rates ranging from 2.5×10-4S-1 to 2.5×10-2S-1. The Fe-Mn-Cu-C TWIP Steels exhibit high work hardening rate and outstanding mechanical properties, The excellent mechanical properties are attributed to dynamic strain aging(DSA) effect, which result from the interaction between Mn(Cu)-C atom atmosphere, C-vacancy, C-C pairs and moving dislocations.

Multiscale Material Modeling and Simulation of the Mechanical Behavior of Dual Phase Steels Under Different Strain Rates: Parametric Study and Optimization

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Tarek M. Belgasam ◽  
Hussein M. Zbib
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Volume Fraction ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dual Phase ◽  
Strain Rates ◽  
Microstructure Parameters ◽  
Dp Steels

Recent studies on developing dual phase (DP) steels showed that the combination of strength/ductility could be significantly improved when changing the volume fraction and grain size of phases in the microstructure depending on microstructure properties. Consequently, DP steel manufacturers are interested in predicting microstructure properties as well as optimizing microstructure design at different strain rate conditions. In this work, a microstructure-based approach using a multiscale material and structure model was developed. The approach examined the mechanical behavior of DP steels using virtual tensile tests with a full micro-macro multiscale material model to identify specific mechanical properties. Microstructures with varied ferrite grain sizes, martensite volume fractions, and carbon content in DP steels were also studied. The influence of these microscopic parameters at different strain rates on the mechanical properties of DP steels was examined numerically using a full micro-macro multiscale finite element method. An elasto-viscoplastic constitutive model and a response surface methodology (RSM) were used to determine the optimum microstructure parameters for a required combination of strength/ductility at different strain rates. The results from the numerical simulations were compared with experimental results found in the literature. The developed methodology proved to be a powerful tool for studying the effect and interaction of key strain rate sensitivity and microstructure parameters on mechanical behavior and thus can be used to identify optimum microstructural conditions at different strain rates.

scholarly journals New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper

2015 ◽  
Vol 60 (2) ◽  
pp. 605-614 ◽  
Author(s):  
T. Kvačkaj ◽  
A. Kováčová ◽  
J. Bidulská ◽  
R. Bidulský ◽  
R. Kočičko
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Wear Behaviour ◽  
Ofhc Copper ◽  
Strain Rates ◽  
Ultrafine Grained ◽  
Reduction Of Area ◽  
Pin On Disk

AbstractIn this study, static, dynamic and tribological properties of ultrafine-grained (UFG) oxygen-free high thermal conductivity (OFHC) copper were investigated in detail. In order to evaluate the mechanical behaviour at different strain rates, OFHC copper was tested using two devices resulting in static and dynamic regimes. Moreover, the copper was subjected to two different processing methods, which made possible to study the influence of structure. The study of strain rate and microstructure was focused on progress in the mechanical properties after tensile tests. It was found that the strain rate is an important parameter affecting mechanical properties of copper. The ultimate tensile strength increased with the strain rate increasing and this effect was more visible at high strain rates$({\dot \varepsilon} \sim 10^2 \;{\rm{s}}^{ - 1} )$. However, the reduction of area had a different progress depending on microstructural features of materials (coarse-grained vs. ultrafine-grained structure) and introduced strain rate conditions during plastic deformation (static vs. dynamic regime). The wear behaviour of copper was investigated through pin-on-disk tests. The wear tracks examination showed that the delamination and the mild oxidational wears are the main wear mechanisms.

Local Investigations of the Mechanical Properties of Ultrafine Grained Metals by Nanoindentations

2006 ◽  
Vol 503-504 ◽  
pp. 31-36 ◽  
Author(s):  
Johannes Mueller ◽  
Karsten Durst ◽  
Dorothea Amberger ◽  
Matthias Göken
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Fcc Metals ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Indentation Strain

The mechanical properties of ultrafine-grained metals processed by equal channel angular pressing is investigated by nanoindentations in comparison with measurements on nanocrystalline nickel with a grain size between 20 and 400 nm produced by pulsed electrodeposition. Besides hardness and Young’s modulus measurements, the nanoindentation method allows also controlled experiments on the strain rate sensitivity, which are discussed in detail in this paper. Nanoindentation measurements can be performed at indentation strain rates between 10-3 s-1 and 0.1 s-1. Nanocrystalline and ultrafine-grained fcc metals as Al and Ni show a significant strain rate sensitivity at room temperature in comparison with conventional grain sized materials. In ultrafine-grained bcc Fe the strain rate sensitivity does not change significantly after severe plastic deformation. Inelastic effects are found during repeated unloading-loading experiments in nanoindentations.

scholarly journals Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Reinforcing Steel ◽  
Test Results ◽  
Cross Sectional ◽  
Steel Bars

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

scholarly journals Strain-Rate-Dependent Deformation Behavior and Mechanical Properties of a Multi-Phase Medium-Manganese Steel

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 344 ◽  
Author(s):  
Simon Sevsek ◽  
Christian Haase ◽  
Wolfgang Bleck
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Manganese Steel ◽  
Strain Rates ◽  
Rate Dependent ◽  
Medium Manganese Steel ◽  
Multi Phase

The strain-rate-dependent deformation behavior of an intercritically annealed X6MnAl12-3 medium-manganese steel was analyzed with respect to the mechanical properties, activation of deformation-induced martensitic phase transformation, and strain localization behavior. Intercritical annealing at 675 °C for 2 h led to an ultrafine-grained multi-phase microstructure with 45% of mostly equiaxed, recrystallized austenite and 55% ferrite or recovered, lamellar martensite. In-situ digital image correlation methods during tensile tests revealed strain localization behavior during the discontinuous elastic-plastic transition, which was due to the localization of strain in the softer austenite in the early stages of plastic deformation. The dependence of the macroscopic mechanical properties on the strain rate is due to the strain-rate sensitivity of the microscopic deformation behavior. On the one hand, the deformation-induced phase transformation of austenite to martensite showed a clear strain-rate dependency and was partially suppressed at very low and very high strain rates. On the other hand, the strain-rate-dependent relative strength of ferrite and martensite compared to austenite influenced the strain partitioning during plastic deformation, and subsequently, the work-hardening rate. As a result, the tested X6MnAl12-3 medium-manganese steel showed a negative strain-rate sensitivity at very low to medium strain rates and a positive strain-rate sensitivity at medium to high strain rates.

Effect of Hot Extrusion on the Flow Behaviour of a Nickel-Based P/M Superalloy

2019 ◽  
Vol 298 ◽  
pp. 43-51
Author(s):  
Jia Yong Si ◽  
Song Hao Liu ◽  
Long Chen
Keyword(s):  
Activation Energy ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Work Hardening ◽  
Rate Sensitivity ◽  
Hot Extrusion ◽  
Turbine Disk ◽  
Flow Behaviour ◽  
Strain Rates ◽  
Work Hardening Rate

This research investigated the effect of hot extrusion on the flow behaviour of nickel-based superalloy FGH4096 by hot compression experiments in the temperature range from 1020 to 1110 °C and strain rates ranging from 0.1 to 0.001 s-1. The influence of the hot extrusion on the initial microstructures, work hardening rate, strain rate sensitivity, and activation energy of deformation were discussed. The results show that the extruded microstructure is constituted by the fine dynamic recrystallisation of grains. The true strain-true stress curves show that the as-HIPed and as-HEXed FGH4096 superalloy present double flow stress peaks and discontinuous flow softening. The as-HEXed FGH4096 is easily dynamically softened at high temperatures and high strain rates compared with as-HIPed microstructures. As for the work hardening rate, the as-HEXed FGH4096 exhibits higher θ values than that of as-HIPed. It is beneficial to the homogenous deformation and grain refinement during subsequent turbine disk forging. Comparing to as-HIPed FGH4096, the highest strain rate sensitivity value of as-HEXed is 0.306 at 1110 °C. The isothermal superplastic forging of a P/M turbine disk may be carried out at this temperature. The deformation activation energy value of the as-HIPed FGH4096 is lower which means that dislocation sliding and climbing can be easily initiated in the as-HIPed alloy.

Effect of Si Content on Fracture Behaviour Change by Strain Rate in Si Steels

2010 ◽  
Vol 654-656 ◽  
pp. 1303-1306 ◽  
Author(s):  
Takashi Mizuguchi ◽  
Ryota Oouchi ◽  
Rintaro Ueji ◽  
Yasuhiro Tanaka ◽  
Kazunari Shinagawa
Keyword(s):  
Strain Rate ◽  
Fracture Behaviour ◽  
Tensile Tests ◽  
Strain Rates ◽  
Wide Range ◽  
Work Hardening Rate ◽  
Brittle Fractures ◽  
Mechanism Transition ◽  
Si Content ◽  
Si Addition

Fracture behaviour transitions due to change in the strain rate in steels with various Si content ranging from 2% to 5 wt% were studied. Room-temperature tensile tests were conducted over wide range of strain rates ranging from 10-3 s-1 to 103 s-1. Concerning of the steels with low Si content (no more than 3%), the nominal stress - nominal strain curves represented both uniform and local elongations at all strain rates. On the other hand, in 4% Si steel at a strain rate higher than 101 s-1, the tensile sample broke down without local elongation (necking). The stress at breaking was found to be nearly equal to its work hardening rate. The strain rate at which fracture behaviour transition took place in 5% Si steel (10-1s-1) was lower than that in 4% Si steel. TEM observations clarified the existence of deformation twins in the sample that fractured without necking. These results indicated that Si addition is subject to the brittle fractures and that the fracture mechanism transition is closely related with the deformation twinning behaviour.

scholarly journals The Temperature and Strain Rate Dependence of the Flow Stress of Single Crystal Nial Deformed Along

1994 ◽  
Vol 364 ◽  
Author(s):  
Stuart A Maloy ◽  
George T Gray
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Single Crystal ◽  
Work Hardening ◽  
Rate Dependence ◽  
Temperature Sensitive ◽  
Strain Rates ◽  
Slip Bands ◽  
Work Hardening Rate ◽  
Slip Traces

AbstractSingle crystal NiAl and Ni-49.75Al-0.25Fe have been deformed along <110> at temperatures of 77, 298 and 773K and strain rates of 0.001/s, 0.1/s and 2000/s. The flow stress of <110> NiAl is rate and temperature sensitive. A significant decrease in the work hardening rate is observed after deformation at 77K and a strain rate of 2000/s. Coarse {110} slip traces are observed after deformation at a strain rate of 2000/s at 77K, while no slip traces were observed after deformation under all other conditions. TEM observations reveal distinct {110} slip bands after deformation at 77K and a strain rate of 2000/s.

Superplasticity of an AA2519 Aluminum Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 278-284
Author(s):  
Ivan Zuiko ◽  
Marat Gazizov ◽  
Rustam Kaibyshev
Keyword(s):  
Strain Rate ◽  
Thermomechanical Processing ◽  
Rate Sensitivity ◽  
Initial Strain Rate ◽  
Tensile Tests ◽  
Sensitivity Coefficient ◽  
Initial Strain ◽  
Strain Rates ◽  
Average Grain Size ◽  
Elongation To Failure

A commercial AA2519 alloy with a chemical composition of Al-5.64Cu-0.33Mn-0.23Mg-0.15Zr (in wt. %) was subjected to two-step thermomechanical processing (TMP) providing the formation of fully recrystallized structure with an average grain size of ~7 mm in 3 mm thin sheets. Superplastic tensile tests were performed in the temperature interval 450-535°C and initial strain rates ranging from ~2.8 x 10-4 to ~6.0 x 10-1 s-1. The highest elongation-to-failure of ~750% appears at a temperature of ~525°C and an initial strain rate of ~1.4 × 10-4 s-1 with the corresponding strain rate sensitivity coefficient of ~0.46.

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