scholarly journals Influence of Volume Fraction of Long-Period Stacking Ordered Structure Phase on the Deformation Processes during Cyclic Deformation of Mg-Y-Zn Alloys

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Daria Drozdenko ◽  
Gergely Farkas ◽  
Pavol Šimko ◽  
Klaudia Fekete ◽  
Jan Čapek ◽  
...  
Keyword(s):  
Path Dependence ◽  
Volume Fraction ◽  
Deformation Mechanisms ◽  
Electron Backscattered Diffraction ◽  
Long Period ◽  
Lpso Structure ◽  
Deformation Processes ◽  
In Situ Neutron Diffraction ◽  
Zn Alloys

Deformation mechanisms in extruded Mg-Y-Zn alloys with different volume fractions of the long-period stacking ordered (LPSO) structure have been investigated during cyclic loading, i.e., compression followed by unloading and reverse tensile loading. Electron backscattered diffraction (EBSD) and in situ neutron diffraction (ND) techniques are used to determine strain path dependence of the deformation mechanisms. The twinning-detwinning mechanism operated in the α-Mg phase is of key importance for the subsequent hardening behavior of alloys with complex microstructures, consisting of α-Mg and LPSO phases. Besides the detailed analysis of the lattice strain development as a function of the applied stress, the dislocation density evolution in particular alloys is determined.

scholarly journals Deformation mechanisms of Mo alloyed FeCoCrNi high entropy alloy: In situ neutron diffraction

2017 ◽  
Vol 127 ◽  
pp. 471-480 ◽  
Author(s):  
Biao Cai ◽  
Bin Liu ◽  
Saurabh Kabra ◽  
Yiqiang Wang ◽  
Kun Yan ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Deformation Mechanisms ◽  
High Entropy Alloy ◽  
High Entropy ◽  
In Situ Neutron Diffraction

Stress-Strain-Temperature Behavior Due to B2-R-B19′ Transformation in NiTi Polycrystals

2006 ◽  
Vol 128 (3) ◽  
pp. 268-278 ◽  
Author(s):  
P. Šittner ◽  
V. Novák ◽  
P. Lukáš ◽  
M. Landa
Keyword(s):  
Micromechanical Modeling ◽  
Recovery Stress ◽  
Electric Resistance ◽  
Stress Tests ◽  
Deformation Processes ◽  
Niti Wires ◽  
In Situ Neutron Diffraction ◽  
Transformation Processes ◽  
Distortion Angle

Thermomechanical behavior of superelastic NiTi wires undergoing sequential B2-R-B19′ martensitic transformation was investigated by two recently developed in-situ experimental methods (in-situ neutron diffraction and combined ultrasonic and electric resistance measurements) capable of detecting and recognizing the activity of various deformation/transformation processes in NiTi and theoretically by micromechanical modeling. An earlier model of SMA polycrystal transformation is further developed, so it accounts for the strains due to the R-phase related deformation processes in activated NiTi. A continuous variation of the rhombohedral distortion angle α of the R-phase structure with temperature and stress is newly introduced as a legitimate deformation mechanism. Simulation results for NiTi bars and wires exposed to three types of thermomechanical tests—mechanical loading at constant temperature, cooling under constant stress, and recovery stress tests are presented and confronted with results.

Deformation mechanisms of a 20Mn TWIP steel investigated by in situ neutron diffraction and TEM

2013 ◽  
Vol 61 (16) ◽  
pp. 6093-6106 ◽  
Author(s):  
Y.F. Shen ◽  
Y.D. Wang ◽  
X.P. Liu ◽  
X. Sun ◽  
R. Lin Peng ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Twip Steel ◽  
Deformation Mechanisms ◽  
In Situ Neutron Diffraction

In Situ Synchrotron Analysis of Twinning Stresses in an Aged Mg-4.5Zn Alloy

2018 ◽  
Vol 941 ◽  
pp. 1579-1584 ◽  
Author(s):  
Mahmoud Reza Ghandehari Ferdowsi ◽  
Jun Wang ◽  
Sitarama R. Kada ◽  
Zhi Yang Wang ◽  
Peter A. Lynch ◽  
...  
Keyword(s):  
Yield Strength ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Aged Condition ◽  
X Ray ◽  
Peak Broadening ◽  
Strong Relation ◽  
Twin Volume Fraction ◽  
Zn Alloys

Aging increases the yield strength of aged Mg-Zn alloys. The effect of aging on the stress required for twinning is examined using in-situ transmission based synchrotron X-ray diffraction. The as extruded material was aged at variety of temperatures for different times. It is found that increasing sample diameter (thickness) results in peak broadening. The data are analysed to establish the evolution of twin volume fraction with stress. Results indicated an increase in twinning stress at 10% twin volume fraction in aged samples in comparison with non-aged condition. The investigation showed a strong relation between the macroscopic yield stress and the twinning stress (at 10% twin volume fraction).

In Situ Neutron Diffraction during Thermo-Mechanically Controlled Process in Low Alloy Steels

2006 ◽  
Vol 118 ◽  
pp. 419-424
Author(s):  
M.S. Koo ◽  
Ping Guang Xu ◽  
J.H. Li ◽  
Yo Tomota ◽  
O. Muransky ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Volume Fraction ◽  
Structural Evolution ◽  
Low Alloy Steels ◽  
Controlled Processing ◽  
Ferrite Transformation ◽  
Alloy Steels ◽  
Time Division ◽  
In Situ Neutron Diffraction

A challenge was made to examine the micro-structural evolution during thermomechanically controlled processing (TMCP) by in situ neutron diffraction. Since the neutron beam is too weak to achieve a time-division measurement to follow a rapid transformation in alow carbon steel, 2%Mn was added to make the austenite to ferrite transformation slower. Round bar specimens were heated up to 900°C with an electrical resistance method, then cooled down to 700°C, and compressed by 25% followed by step-by-step cooling. During the step-by-step cooling, neutron diffraction profiles were obtained and the volume fraction of ferrite, phase stresses and FWHM were analyzed. Using a similar TMCP simulator, specimens were quenched into water at several stages of the heat schedule to freeze the corresponding microstructures, which were observed with OM and SEM. As results, the ferrite volume fraction determined by neutron diffraction on cooling agrees well with that by microscopy. It is found that the austenite deformation and/or Nb addition accelerate the ferrite transformation to result in finer grain size.

Investigation of Forming Conditions on Microstructure Development and Mechanical Stability of Trip Steel

2008 ◽  
Vol 575-578 ◽  
pp. 1396-1401
Author(s):  
Jozef Zrník ◽  
O. Murnsky ◽  
Peter Horňak ◽  
Martin Fujda
Keyword(s):  
Trip Steel ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Structural Characteristics ◽  
Transformation Induced Plasticity ◽  
In Situ Neutron Diffraction ◽  
Neutron Diffraction Technique ◽  
Kinetics Of

Experimental simulations of thermomechanical processing (TM) using press forging of Si-Mn TRIP (transformation induced plasticity) steel were performed. In order to rationalize the retained austenite (RA) volume fraction, six TM schedules were employed at experiment where different austenite conditioning was considered. The various multiphase structure characteristics were obtained after of TM processing, with different volume fraction of ferrite, bainite and RA. The modification of structural characteristics influenced the mechanical properties of TRIP steel. The present work also focuses on monitoring of RA transformation during mechanical incremental straining using in situ neutron diffraction technique. This method is used to characterize the kinetics of RA transformation and its stability during the straining.

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