Cyclic Deformation Of B2 Aluminides

1990 ◽  
Vol 213 ◽  
Author(s):  
S.E. Hartfield-Wünsch ◽  
R. Gibala
Keyword(s):  
Plastic Strain ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Tensile Ductility ◽  
Cyclic Hardening ◽  
Compression Tests ◽  
Von Mises Criterion ◽  
Thin Nickel ◽  
Von Mises ◽  
Rapidly Solidified

ABSTRACTA study has been undertaken to understand the cyclic deformation behavior of singlephase B2 aluminides. The alloys chosen for this study were rapidly solidified powder extrusions of Fe60 Al40 (at.%) and Ni50 A130 Fe20 (at.%). These alloys were chosen to compare the cyclic deformation behavior of a material that deforms by <111> slip and thus meets the von Mises criterion for slip system compatibility (Fe60Al40) with one that deforms by <100> slip and does not meet the von Mises criterion (Ni50A130Fe20). Fully reversed tension/compression tests were run in plastic strain control at room temperature. Rapid cyclic hardening was observed for the Fe60Al40 alloy. However, intergranular failure occurred before saturation was reached at all plastic strain amplitudes. The Ni50A130Fe20 alloy displays no tensile ductility , with failure occurring before completion of the first cycle. For the Ni50A130Fe20 alloy, a lower extrusion temperature during materials processing, and compressive prestrain both increase the cyclic accumulated plastic strain to failure, as well as the monotonic tensile ductility. This made cyclic deformation of the Ni50Al30Fe20 alloy possible. In this alloy, limited cyclic hardening is followed by saturation. For both the Fe60Al40 and Ni50 Al30Fe20 alloys, significant ductility enhancement was achieved by the application of thin nickel films. All cyclic deformation results are compared to similar monotonic tension results and are discussed in terms of the dislocation substructures observed.

Influence of Cyclic Deformation Induced Phase Transformation on the Fatigue Behavior of the Austenitic Steel X6CrNiNb1810

2014 ◽  
Vol 891-892 ◽  
pp. 1231-1236 ◽  
Author(s):  
Andreas Sorich ◽  
Marek Smaga ◽  
Dietmar Eifler
Keyword(s):  
Phase Transformation ◽  
Fatigue Life ◽  
Austenitic Steel ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Martensite Formation ◽  
Destructive Testing

The austenitic steel X6CrNiNb1810 (AISI 347) was investigated in isothermal total strain-controlled tests at ambient temperature and T = 300 °C in the LCF-and HCF-range. The phase transformation from paramagnetic austenite (fcc) into ferromagnetic α´-martensite ́(bcc) leads to cyclic hardening and to an increase in fatigue life. At 300 °C no α´-martensite formation was observed in the LCF-range and the cyclic deformation behavior depends basically on cyclic hardening processes due to an increase of the dislocation density, followed by cyclic saturation and softening due to changes in the dislocation structure. In the HCF-range an increase in fatigue life was observed due to ε- and α´-martensite formation. Measurements of the mechanical stress-strain-hysteresis as well as temperature and magnetic properties enable a characterization of the cyclic deformation behavior and phase transformation in detail. The changes in the physical data were interpreted via microstructural changes observed by scanning-and transmission-electron-microscopy as well as by x-ray investigations. Additionally electromagnetic acoustic transducers (EMATs) developed from the Fraunhofer Institute of Non-destructive Testing (IZFP) Saarbrücken were used for an in-situ characterization of the fatigue processes.

Flow and Fracture Behavior of NiAl in Relation to the Brittle-Toductile Transition Temperature

1990 ◽  
Vol 213 ◽  
Author(s):  
R.D. Noebe ◽  
R.R. Bowman ◽  
C.L. Cullers ◽  
S.V. Raj
Keyword(s):  
Transition Temperature ◽  
Flow Behavior ◽  
Polycrystalline Materials ◽  
Compression Tests ◽  
Dislocation Glide ◽  
Von Mises Criterion ◽  
Tension And Compression ◽  
Ductile Behavior ◽  
Von Mises ◽  
Increasing Temperature

ABSTRACTNiAl has only three independent slip systems operating at low and intermediate temperatures whereas five independent deformation mechanisms are required to satisfy the von Mises criterion for general plasticity in polycrystalline materials. Yet, it is generally recognized that polycrystalline NiAl can be deformed extensively in compression at room temperature and that limited tensile ductility can be obtained in extruded materials. In order to determine whether these results are in conflict with the von Mises criterion, tension and compression tests were conducted on powder-extruded, binary NiAl between 300 and 1300 K. The results indicate that below the brittle-to-ductile transition temperature (BDTT) the failure mechanism in NiAl involves the initiation and propagation of cracks at the grain boundaries which is consistent with the von Mises analysis. Furthermore, evaluation of the flow behavior of NiAl indicates that the transition from brittle to ductile behavior with increasing temperature coincides with the onset of recovery mechanisms such as dislocation climb. The increase in ductility above the BDTT is therefore attributed to the climb of <001> type dislocations which in combination with dislocation glide enable grain boundary compatibility to be maintained at the higher temperatures.

Cyclic deformation behavior of an Fe-Ni-Cr alloy at 700 °C: microstructural evolution and cyclic hardening model

2019 ◽  
Vol 744 ◽  
pp. 94-111 ◽  
Author(s):  
Haizhou Li ◽  
Hongyang Jing ◽  
Lianyong Xu ◽  
Lei Zhao ◽  
Yongdian Han ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Cyclic Hardening ◽  
Hardening Model

scholarly journals Influence of the surface morphology on the cyclic deformation behavior of HSD® 600 steel

2018 ◽  
Vol 165 ◽  
pp. 06010 ◽  
Author(s):  
Matthias W. Klein ◽  
Marek Smaga ◽  
Tilmann Beck
Keyword(s):  
Surface Morphology ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Single Step ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Surface Morphologies

The presented research work investigates the fatigue properties in the low cycle fatigue (LCF) regime of the high manganese metastable austenitic High Strength and Ductility (HSD®) 600 TWIP steel dependent on its surface morphology. The steel features, according to its chemical composition following the alloying concept Mn-Al-Si-C and heat treatment, a fully austenitic microstructure that shows deformation induced twinning at ambient temperature. Due to this microstructural deformation mechanism, HSD® 600 steel has an outstanding combination of strength and formability. Besides monotonic deformation behavior, characterized by tensile tests, cyclic deformation behavior was investigated with varying the surface morphology of fatigue specimens. In order to create different surface morphologies, flat fatigue specimens were excised from larger sheets by waterjet-cutting. Depending on the surface morphology, further climb milling or up-climb milling in the gauge length was performed. The three investigated morphologies (asreceived with rolling skin, climb milled and up-climb milled) differed in roughness, initial residual stresses and initial phase compositions. For all variants, total strain controlled fatigue tests with stepwise increasing load amplitudes as well as total strain controlled single step tests were performed in the low cycle fatigue regime with a load ratio of Rε = -1 and a frequency of f = 0.2 Hz. Beside stress-strain hystereses, the changes in temperature ΔT and the magnetic properties ξ were measured. The magnetic properties directly correlate with the transformation from paramagnetic γ-austenite to ferromagnetic α’-martensite. The cyclic deformation behavior of the HSD® 600 steel in the LCF regime was characterized by cyclic softening until fracture at low total strain amplitudes but changed with increasing total strain amplitudes into initial cyclic hardening followed by cyclic softening. This initial cyclic hardening became more pronounced when the total strain amplitude increased. Furthermore, single step tests at lower total strain amplitudes showed a saturation state before fracture. A comparison between the monotonic and cyclic deformation behavior showed a significant difference of the stress levels at the same amounts of plastic deformation respectively. Nevertheless, the different surface morphologies led to different lifetimes at high total strain amplitudes but to similar lifetimes at lower total strain amplitudes.

Effect of strain rate induced M23C6 distribution on cyclic deformation behavior: Cyclic hardening model

2020 ◽  
Vol 127 ◽  
pp. 102634 ◽  
Author(s):  
Haizhou Li ◽  
Hongyang Jing ◽  
Lianyong Xu ◽  
Yongdian Han ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Cyclic Hardening ◽  
Hardening Model

scholarly journals An elastoplastic finite element study of cylindrical plane-strain contact for steel/steel and Inconel 617/Incoloy 800H undergoing unidirectional sliding

2019 ◽  
Vol 234 (1) ◽  
pp. 126-133
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Coefficient Of Friction ◽  
Tangential Force ◽  
Leading Edge ◽  
Effective Coefficient ◽  
Incoloy 800H ◽  
Inconel 617 ◽  
Von Mises ◽  
Sliding Distance

The current work employs a two-dimensional plane strain finite element analysis to investigate the unidirectional sliding contact between a deformable half-cylinder and a deformable flat block. The unidirectional sliding is governed by a displacement-controlled action where the materials of the two contacting bodies are first set to identical steels at 20 ℃ and then to Inconel 617 and Incoloy 800H at 800 ℃. First, a normal interference (indentation) is applied, which is followed by unidirectional sliding. The von Mises stress distribution, plastic strain distribution, junction growth, normal force, tangential force, effective coefficient of friction, and scars on the surface of the block are obtained during the sliding motion. The leading edge of the contacting area and the bulk material under the leading edge experience large von Mises stresses. The large plastic strain is found on the surface of the block, and forms a “pocket” shape under the surface. The junction growth is also investigated, showing the direction of the growth is in the same direction of the tangential force that the weaker material experiences. The forces and the effective coefficient of friction are found to stabilize after a certain sliding distance, and the effective coefficient of friction converges to the coefficient of friction used in the model. Pileup is found on the surface of the block after a sufficient unidirectional sliding distance.

On the effect of precipitates on the cyclic deformation behavior of an Al–Mg–Si alloy

2017 ◽  
Vol 32 (23) ◽  
pp. 4398-4410 ◽  
Author(s):  
Haichun Jiang ◽  
Stefanie Sandlöbes ◽  
Günter Gottstein ◽  
Sandra Korte-Kerzel
Keyword(s):  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Image Position

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