scholarly journals A New Method of Predicting the Structural and Mechanical Change of Materials during Extrusion by the Method of Multiple Plastic Deformations

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2594
Author(s):  
Marta Harničárová ◽  
Jan Valíček ◽  
Milena Kušnerová ◽  
Zuzana Palková ◽  
Ivan Kopal ◽  
...  
Keyword(s):  
Grain Size ◽  
Close Correlation ◽  
Ultrasonic Waves ◽  
Technological Parameters ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
New Equation ◽  
Mechanical Change ◽  
Longitudinal Ultrasonic Waves

The formulation of the Hall–Petch relationship in the early 1950s has raised immense interest in studying the influence of the grain size of solid materials on their properties. Grain refinement can be achieved through extreme deformation. In the presented study, Equal-Channel Angular Pressing (ECAP) was successfully applied to produce an ultrafine-grained microstructure in a pure commercial Cu of 99.9 wt%. Samples were processed by ECAP at 21 °C for six passes via route A. A new equation of equilibrium that allows the exact determination of the number of extrusions and other technological parameters required to achieve the desired final grain size has been developed. The presented research also deals, in a relatively detailed and comparative way, with the use of ultrasound. In this context, a very close correlation between the process functions of extrusion and the speed of longitudinal ultrasonic waves was confirmed.

Determination of the foaming parameters of polyurethane compositions from the velocity of longitudinal ultrasonic waves

1979 ◽  
Vol 15 (3) ◽  
pp. 316-317 ◽  
Author(s):  
V. M. Mel'nikov ◽  
�. A. Putnin'sh ◽  
V. O. Putninya ◽  
V. P. Karlivan
Keyword(s):  
Ultrasonic Waves ◽  
Longitudinal Ultrasonic Waves

Phase Mixture Models for Metallic Materials with Submicrometer Grain Size

2003 ◽  
Vol 791 ◽  
Author(s):  
Yuri Estrin ◽  
Hyoung Seop Kim ◽  
Mark Bush
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mixture Models ◽  
Cell Walls ◽  
Mechanical Response ◽  
Metallic Materials ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Model Predictions ◽  
Phase Mixture

ABSTRACTPhase mixture models describing the mechanical properties of submicrometer grained metals are presented. In this approach, grain boundaries or cell walls are treated as a separate phase. Two cases are considered: the mechanical response of an ultrafine grained material and the process of grain refinement by equal channel angular pressing. Model predictions with regard to the evolution of the microstructure, strength and texture are verified for Cu.

scholarly journals Ultrasonic attenuation in lead

1963 ◽  
Vol 271 (1344) ◽  
pp. 88-104 ◽  
Keyword(s):  
Magnetic Field ◽  
Ultrasonic Attenuation ◽  
Absolute Magnitude ◽  
Transverse Magnetic ◽  
Ultrasonic Waves ◽  
Acoustic Oscillations ◽  
Connected Surface ◽  
Sample Orientation ◽  
Longitudinal Ultrasonic Waves

The absorption of longitudinal ultrasonic waves has been studied as a function of transverse magnetic field in pure single crystals of lead at 1.2 °K. The results were found to be generally consistent with the Fermi surface of lead suggested by Gold. In particular a detailed study of the magneto-acoustic oscillations, as a function of sample orientation and field direction, allowed the determination of some of the dimensions of the hole surface in the second Brillouin zone and revealed a number of new electronic orbits on the multiply-connected surface in the third zone. The absolute magnitude of the attenuation and its dependence on propagation direction and on magnetic field was studied and the results interpreted in terms of the general theory of ultrasonic absorption.

Attenuation and Velocity of Ultrasonic Waves in Amorphous Selenium in the Vicinity of the Glass Transition

1977 ◽  
Vol 32 (9) ◽  
pp. 946-951
Author(s):  
Erwin Kittinger
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Ultrasonic Waves ◽  
Amorphous Selenium ◽  
Approximate Determination ◽  
Stabilization Process ◽  
Nonequilibrium States ◽  
Longitudinal Ultrasonic Waves

AbstractAttenuation and velocity of longitudinal ultrasonic waves have been measured in a-Se in the vicinity of the glass transition. Both quantities are shown to be affected significantly by the stabilization process below the glass transition temperature Tg. Equilibrium values of sound velocity are also reported for the range 25 °C to 45 °C. The decrease (increase) of attenuation (velocity) during stabilization is reversed at higher temperatures. The connection of both quantities is discussed in terms of an effective temperature which allows the approximate determination of equilibrium values of attenuation (and possibly of other structure related properties) from measurements performed in nonequilibrium states.

scholarly journals Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Rifai ◽  
Hiroyuki Miyamoto ◽  
Hiroshi Fujiwara
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Strain Energy ◽  
Early Stage ◽  
Pitting Potential ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
C And N ◽  
Cr Steels ◽  
Lower Temperature

Effect of strain energy and grain size on corrosion resistance of ultrafine grained (UFG) Fe-20%Cr steels with extremely low C and N fabricated by equal channel angular pressing (ECAP) was investigated. UFG structures of initial grain size of 144 nm exhibited the typical three-stage softening comprising recovery, recrystallization, and grain growth. Potentiodynamic polarization measurements were carried out with a conventional three-electrode cell to evaluate pitting potential. Pitting potential in 1000 mol·m−3NaCl solution was nobler in UFG state, but pitting potential started to decrease monotonously at lower temperature compared to hardness. The degradation of corrosion resistance in the early stage of annealing is attributed to stability change of passivation by recovery of dislocation structures inside grains and in nonequilibrium grain boundaries. We therefore conclude that nobler potentials of UFG states were realized by not only grain size reduction but also defective deformation-induced UFG.

Grain Refinement of Copper Alloys by Equal Channel Angular Pressing

2004 ◽  
Vol 449-452 ◽  
pp. 177-180 ◽  
Author(s):  
Cha Yong Lim ◽  
Jae Hyuck Jung ◽  
Seung Zeon Han
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Copper Alloys ◽  
Metallic Materials ◽  
Fine Grained ◽  
Angular Pressing ◽  
Fine Grain ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Average Grain Size

The equal channel angular pressing (ECAP) is one of the methods to refine the grain size of metallic materials. This study investigates the effect of ECAP process on the formation of the fine grain size in oxygen free Cu and Cu alloys. The average grain size has been refined from 150 µm before ECAP to 300 nm. Microstructure was analyzed by transmission electron micrography (TEM). The diffraction pattern of the selected area confirmed the formation of ultrafine-grained structure with high angle grain boundaries after 8 cycles of ECAP. Mechanical properties such as microhardness and tensile properties of the ultra-fine grained copper materials have been investigated.

Structure and Fatigue Properties of the Mg Alloy AM60 Processed by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 803-808 ◽  
Author(s):  
Rinat K. Islamgaliev ◽  
Olya B. Kulyasova ◽  
Bernhard Mingler ◽  
Michael Zehetbauer ◽  
Alexander Minkow
Keyword(s):  
Grain Size ◽  
Endurance Limit ◽  
Volume Fraction ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
Fatigue Endurance ◽  
Misorientation Angles

This paper reports on the microstructures and fatigue properties of ultrafine-grained (UFG) AM60 magnesium alloy processed by equal channel angular pressing (ECAP) at various temperatures. After ECAP processing, samples exhibited an increase in fatigue endurance limit, which correlates well with a decrease in grain size. In case of lowest ECAP temperature, the mean grain size is as small as 1 2m which leads to an increase in fatigue endurance limit by 70 % in comparison to coarse-grained alloy. The temperature of ECAP not only governs the grain size and misorientation angles of grain boundaries but also the volume fraction of precipitates, thus affecting the probability of twinning and grain growth after fatigue treatment.

Microstructure and Properties of Ti Rods Produced by Multi-Step SPD

2006 ◽  
Vol 503-504 ◽  
pp. 763-768 ◽  
Author(s):  
V.V. Latysh ◽  
Irina P. Semenova ◽  
G.H. Salimgareeva ◽  
I.V. Kandarov ◽  
Yuntian T. Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Stress ◽  
Equal Channel Angular Pressing ◽  
Thermomechanical Treatment ◽  
Ultrafine Grained Structure ◽  
Annealed State ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Cp Ti

This paper studies the effect of combined SPD treatment on microstructure and mechanical properties of semi-products out of CP Ti. The combined processing, consisting of equal-channel angular pressing and further thermomechanical treatment, produced ultrafine-grained rods out of Grade 2 CP Ti with a diameter of 6.5 mm and a length of up to 1 m. It was established that the formation of homogeneous ultrafine-grained structure in Ti rod with α-grain size of about 100 nm allowed to enhance yield stress by 200% in comparison with initial annealed state.

The Mechanical Properties in the Vicinity of Grain Boundaries in Ultrafine-Grained and Polycrystalline Materials Studied by Nanoindentations

2004 ◽  
Vol 819 ◽  
Author(s):  
E. Schweitzer ◽  
K. Durst ◽  
D. Amberger ◽  
M. Göken
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Boundaries ◽  
Rate Sensitivity ◽  
Dislocation Motion ◽  
Polycrystalline Materials ◽  
Petch Relation ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Second Phases

AbstractThe strength of structural materials strongly depends on the structure and properties of grain boundaries. Interfaces usually act as barriers to dislocation motion and therefore strengthen materials with decreasing grain size, quantitatively described by the well-known Hall-Petch relation. However, interfaces in nanocrystalline materials are often covered with impurities or second phases, which may influence the mechanical properties. With nanoindentation testing it is now possible to probe the strength of interfaces like grain boundaries directly on a nanometer scale. Therefore this method was used to investigate the properties in the vicinity of grain boundaries in polycrystalline materials with conventional grain size and in ultrafine-grained metals prepared by equal channel angular pressing (ECAP), where no impurities are introduced during processing. Measurements on an austenitic steel clearly show a decreasing hardness close to the interface opposite to the general expected behavior of strengthening. In this case segregation effects strongly influence the mechanical properties near the boundaries. The nanoindentation investigations on ultrafine-grained Al and Cu show a strong strain rate sensitivity. Inelastic effects are also found between unloading-loading segments during indentations.

Effect of Deformation Structure on Strength of a Low Alloyed Cu-Cr-Zr Alloy

2016 ◽  
Vol 879 ◽  
pp. 1332-1337 ◽  
Author(s):  
A. Morozova ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Strength Properties ◽  
Deformation Structure ◽  
Initial State ◽  
Continuous Dynamic Recrystallization ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Continuous Dynamic ◽  
Zr Alloy

The microstructure evolution and strength properties of a Cu-0.096%Cr-0.057%Zr alloy subjected to equal channel angular pressing (ECAP) at a temperature of 673 K via route BC to total strains of 1 to 4 were examined. The planar low-angle boundaries with moderate misorientations form within initial grains during the first ECAP passes. Upon further processing the misorientations of these boundaries progressively increase and the formation of new ultrafine grains occurs as a result of continuous dynamic recrystallization. Partially recrystallized ultrafine grained structure evolves at strains above 4. After straining to 4 the (sub) grain size attains 0.65 μm. The large plastic straining provides significant strengthening. The ultimate tensile strength increases from 190 MPa in the initial state to 420 MPa after 4 ECAP passes. A modified Hall-Petch analysis is applied to investigate the contribution of grain refinement and dislocation density to the overall strengthening.

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