scholarly journals Phenomenological Models and Peculiarities of Evaluating Fatigue Life of Aluminum Alloys Subjected to Dynamic Non-Equilibrium Processes

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1625
Author(s):  
Mykola Chausov ◽  
Andrii Pylypenko ◽  
Pavlo Maruschak ◽  
Abdellah Menou
Keyword(s):  
Fatigue Life ◽  
Aluminum Alloys ◽  
Structural Changes ◽  
Model Parameters ◽  
Initial State ◽  
Equilibrium Processes ◽  
Alloy Hardness ◽  
Mechanical Models ◽  
Limiting Parameters ◽  
Non Equilibrium

Physical-mechanical models for predicting the fatigue life of aluminum alloys D16ChATW and 2024-T351 are proposed and tested. Damage accumulation patterns are established for these alloys in the initial state and after dynamic non-equilibrium processes (DNP) of different intensity that occur at maximum cycle stresses σmax from 340 to 440 MPa, cycle asymmetry coefficients R = 0.1 and load frequency f = 110 Hz. The main model parameters are the initial alloy hardness HV and the limiting parameters of scatter of hardness values m. These parameters are evaluated in the process of cyclic loading with fixed maximum stresses of the cycles. Relative values me are also considered. For the alloys in the initial state, the proposed models are shown to be in good agreement with the experimental results. Conversely, structural changes taking place in alloys after DNP complicate the prediction of their fatigue life.

Specifics Deformation Aluminium Alloy D16 in Conditions Additional Load Impulse

2014 ◽  
Vol 598 ◽  
pp. 99-104 ◽  
Author(s):  
Dorota Kocańda ◽  
Volodymyr Hutsaylyuk ◽  
Mykola Czausow ◽  
Valentin Berezin ◽  
Andriy Sobchak
Keyword(s):  
Aluminium Alloy ◽  
Elastic Waves ◽  
Structural Changes ◽  
Dynamic Deformation ◽  
Deformation Field ◽  
High Plasticity ◽  
Additional Load ◽  
Equilibrium Processes ◽  
Propagation Of Elastic Waves ◽  
Non Equilibrium

The technique of recording the changes in the dynamic deformation field of non-equilibrium processes in the alloys of aluminum. It was established experimentally that the structural changes are implemented in the propagation of elastic waves in the material deformation. Qualitatively be characterized distribution of high plasticity surface of the specimen and determined its size after realization of dynamic non-equilibrium processes.

Multiplexed Laser Induced Fluorescence and Non-Equilibrium Processes in Arcjets.

1994 ◽  
Author(s):  
Dennis Keefer ◽  
Robert Rhodes ◽  
Trevor Moeller ◽  
David Burtner
Keyword(s):  
Laser Induced Fluorescence ◽  
Equilibrium Processes ◽  
Non Equilibrium

scholarly journals Modeling Northern Hemisphere Summer Heat Extreme Changes and Their Uncertainties Using a Physics Ensemble of Climate Sensitivity Experiments

2006 ◽  
Vol 19 (17) ◽  
pp. 4418-4435 ◽  
Author(s):  
Robin T. Clark ◽  
Simon J. Brown ◽  
James M. Murphy
Keyword(s):  
Structural Changes ◽  
Heat Waves ◽  
Full Range ◽  
Daily Maximum ◽  
Model Parameters ◽  
Mean Values ◽  
Summer Heat ◽  
Modeling Uncertainties ◽  
Physics Ensemble ◽  
Projected Changes

Abstract Changes in extreme daily temperature events are examined using a perturbed physics ensemble of global model simulations under present-day and doubled CO2 climates where ensemble members differ in their representation of various physical processes. Modeling uncertainties are quantified by varying poorly constrained model parameters that control atmospheric processes and feedbacks and analyzing the ensemble spread of simulated changes. In general, uncertainty is up to 50% of projected changes in extreme heat events of the type that occur only once per year. Large changes are seen in distributions of daily maximum temperatures for June, July, and August with significant shifts to warmer conditions. Changes in extremely hot days are shown to be significantly larger than changes in mean values in some regions. The intensity, duration, and frequency of summer heat waves are expected to be substantially greater over all continents. The largest changes are found over Europe, North and South America, and East Asia. Reductions in soil moisture, number of wet days, and nocturnal cooling are identified as significant factors responsible for the changes. Although uncertainty associated with the magnitude of expected changes is large in places, it does not bring into question the sign or nature of the projected changes. Even with the most conservative simulations, hot extreme events are still expected to substantially increase in intensity, duration, and frequency. This ensemble, however, does not represent the full range of uncertainty associated with future projections; for example, the effects of multiple parameter perturbations are neglected, as are the effects of structural changes to the basic nature of the parameterization schemes in the model.

Additional Non Equilibrium Processes in the Dynamic Interaction between Flux Quanta and Defects

2006 ◽  
Author(s):  
S. Pace ◽  
G. Filatrella ◽  
G. Grimaldi ◽  
A. Nigro ◽  
M. G. Adesso
Keyword(s):  
Dynamic Interaction ◽  
Equilibrium Processes ◽  
Non Equilibrium

Self-Organisation of the Heat Resistant Steel Structure Following Dynamic Non-Equilibrium Processes

2015 ◽  
Vol 220-221 ◽  
pp. 917-921 ◽  
Author(s):  
Mykola Chausov ◽  
Pavlo Maruschak ◽  
Olegas Prentkovskis ◽  
Andriy Pylypenko ◽  
Valentyn Berezin ◽  
...  
Keyword(s):  
Dissipative Structure ◽  
Steel Structure ◽  
Image Correlation ◽  
Experimental Methodology ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Equilibrium Processes ◽  
Equilibrium Process ◽  
Non Equilibrium

Using an original experimental methodology and software for contactless investigation into strains applying the method of digital image correlation, conditions for DNP realization in the test setup with pre-set rigidity have been found. Strain velocities have been determined to be equal to 2...10 s–1 in the processes of forming and developing a dissipative structure of heat resistant steel under the DNP (dynamic non-equilibrium process).

scholarly journals A study into the structure and physical properties of the Cr18Ni9-grade steel following long-term irradiation as part of the BN-600 reactor internals

2020 ◽  
Vol 6 (1) ◽  
pp. 1-6
Author(s):  
Irina A. Portnykh ◽  
Aleksandr V. Kozlov ◽  
Valery L. Panchenko ◽  
Vyacheslav S. Shikhalev
Keyword(s):  
Physical Properties ◽  
Young’S Modulus ◽  
Structural Changes ◽  
Young's Modulus ◽  
Void Size ◽  
Initial State ◽  
Porosity Distribution ◽  
Grade Steel ◽  
Reactor Internals

The microstructures and physical properties of the austenitic Cr18Ni9-grade steel after 22 and 33 years of operation as part of the reactor internals were tested for assessing the conditions of the BN-600 reactor non-replaceable components (internals) and the potential of their subsequent use in predicting the reactor ultimate life. The paper presents histograms of the porosity distribution depending on the void size, in samples taken from portions that were subjected to neutron irradiation with displacement rates ranging from 1.0×10–9 to 4.3×10–8 dpa/s at temperatures from 370 to 440 °C. The elasticity characteristics were measured by resonance-type ultrasonic technique for the samples taken from the same portions of material. It was demonstrated that swelling calculated using the histograms of the porosity distribution depending on the void size has the maximum value at ~415 °C and after 33 years of irradiation reaches values of ~3%. Long-term variations of Young’s modulus demonstrate non-monotonous dependence on the damage dose. The maximum relative variation of Young’s modulus after 22 and 33 years of operation does not exceed 2% and 6%, respectively, of the values corresponding to the initial state. It was shown that along with the irradiation-induced swelling the changes in the physical properties are also affected in the process of irradiation by other structural changes and, in particular, by the formation of secondary phases. As shown by the results of the studies, operation of the BN-600 reactor internals made of Cr18Ni9-grade steel can be extended beyond 33 years of service. The comparison of the results obtained for the material after 22 and 33 years of operation contains information required for describing subsequent changes of the structure and properties of the Cr18Ni9 internals. The obtained results can be used for forecasting the reactor ultimate life within the framework of existing and developed models.

scholarly journals Influence of the energy electron beam exposure regimes on the structure and mechanical properties of composite coatings

2020 ◽  
pp. 23-27
Author(s):  
T.A. Krylova ◽  
◽  
Y.A. Chumakov ◽  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Electron Beam ◽  
Structural Changes ◽  
Composite Coatings ◽  
Initial State ◽  
Austenitic Structure ◽  
Solid Carbide ◽  
Soft Ferrite

The effect of heat treatment on the structure and properties of composite coatings based on chromium carbide with titanium carbide fabricated by non-vacuum electron beam cladding without has been studied. It was shown that tempering leads to a decrease in microhardness and wear resistance, which is associated with the decomposition of the austenitic structure with the formation of a soft ferrite-carbide structure. The post heat treatment tempering was showed to decrease of microhardness and wear resistance, which leads to the decomposition of the austenitic structure with the formation of a soft ferrite-carbide structure. The bulk quenching of coatings after tempering leads to an increase in microhardness comparable to the values of microhardness in the initial state after electron beam cladding, due to the formation of high hard martensite. The wear resistance of composite coatings after tempering is lower than after cladding due to brittle martensite, which is not able to hold solid carbide particles. The composite coatings obtained at the optimal processing conditions have a combination of improved properties and do not require additional heat treatment, resulting in structural changes, causing a decrease in mechanical properties.

Sign in / Sign up

Export Citation Format

Share Document