Crystal plasticity in shock-compressed hcp-iron

2021 ◽  
Author(s):  
Sébastien Merkel ◽  
Sovanndara Hok ◽  
Cynthia Bolme ◽  
Wendy Mao ◽  
Arianna Gleason
Keyword(s):  
Free Electron ◽  
Deformation Mechanisms ◽  
Free Electron Lasers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Planetary Cores ◽  
Materials Behavior ◽  
Optical Laser

<p>Iron is a key constituent of planetary core and an important technological material. Here, we combine <em>in situ</em> ultrafast X-ray diffraction at free electron lasers with optical-laser-induced shock compression experiments on polycrystalline Fe to study the plasticity of hexagonal close-packed (hcp)-Fe under extreme loading states. We identifiy the deformation mechanisms that controls the Fe microstructures and  observe a significant time-evolution of stress over the few nanoseconds of the experiments. These observations illustrate how ultrafast plasticity studies can reveal distinctive materials behavior under extreme loading states and will help constraining the pressure, temperature, and strain rate dependence of materials behavior in planetary cores.</p>

scholarly journals Footprints of deformation mechanisms during in situ x-ray diffraction: Nanocrystalline and ultrafine grained Ni

2005 ◽  
Vol 86 (23) ◽  
pp. 231910 ◽  
Author(s):  
Z. Budrovic ◽  
S. Van Petegem ◽  
P. M. Derlet ◽  
B. Schmitt ◽  
H. Van Swygenhoven ◽  
...  
Keyword(s):  
Deformation Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrafine Grained

scholarly journals In Situ Synchrotron X-ray Diffraction Investigations of the Nonlinear Deformation Behavior of a Low Modulus β-Type Ti36Nb5Zr Alloy

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1619
Author(s):  
Qingkun Meng ◽  
Huan Li ◽  
Kai Wang ◽  
Shun Guo ◽  
Fuxiang Wei ◽  
...  
Keyword(s):  
Elastic Deformation ◽  
Deformation Behavior ◽  
Nonlinear Deformation ◽  
Deformation Mechanisms ◽  
X Ray Diffraction ◽  
Recoverable Strain ◽  
X Ray ◽  
Ti Alloys ◽  
Low Modulus

The low modulus β-type Ti alloys usually have peculiar deformation behaviors due to their low phase stability. However, the study of the underlying mechanisms is challenging since some physical mechanisms are fully reversible after the release of the load. In this paper, the deformation behavior of a low modulus β-type Ti36Nb5Zr alloy was investigated with the aid of in situ synchrotron X-ray diffraction (SXRD) during tensile loading. The evolution of lattice strains and relative integrated diffraction peak intensities of both the β and α” phases were analyzed to determine the characteristics of the potential deformation mechanisms. Upon loading, the α” diffraction spots appeared at specific azimuth angles of the two-dimensional SXRD patterns due to the <110> fiber texture of original β grains and the selection of favorable martensitic variants. The nonlinear deformation behavior originated from a reversible stress-induced martensitic transformation (SIMT). However, the SIMT contributed a little to the large recoverable strain of over 2.0%, which was dominated by the elastic deformation of the β phase. Various deformation mechanisms were activated successively at different applied strains, including elastic deformation, SIMT and plastic deformation. Our investigations provide in-depth understandings of the deformation mechanisms in β-type Ti alloys with low elastic modulus.

scholarly journals Time-resolved resonant soft x-ray diffraction with free-electron lasers: Femtosecond dynamics across the Verwey transition in magnetite

2011 ◽  
Vol 98 (18) ◽  
pp. 182504 ◽  
Author(s):  
N. Pontius ◽  
T. Kachel ◽  
C. Schüßler-Langeheine ◽  
W. F. Schlotter ◽  
M. Beye ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Lasers ◽  
X Ray Diffraction ◽  
Verwey Transition ◽  
Time Resolved ◽  
X Ray ◽  
Femtosecond Dynamics

scholarly journals Formation and annihilation of stressed deformation twins in magnesium

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Karim Louca ◽  
Hamidreza Abdolvand ◽  
Charles Mareau ◽  
Marta Majkut ◽  
Jonathan Wright
Keyword(s):  
Mechanical Response ◽  
Axial Stress ◽  
Three Dimensional ◽  
Service Performance ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
Sign Reversal ◽  
X Ray ◽  
Hexagonal Close Packed

AbstractThe mechanical response of polycrystalline materials to an externally applied load and their in-service performance depend on the local load partitioning among the constituent crystals. In hexagonal close-packed polycrystals such load partitioning is significantly affected by deformation twinning. Here we report in-situ compression-tension experiments conducted on magnesium specimens to measure the evolution of grain resolved tensorial stresses and formation and annihilation of twins. More than 13000 grains and 1300 twin-parent pairs are studied individually using three-dimensional synchrotron X-ray diffraction. It is shown that at the early stages of plasticity, the axial stress in twins is higher than that of parents, yet twins relax with further loading. While a sign reversal is observed for the resolved shear stress (RSS) acting on the twin habit plane in the parent, the sign of RSS within the majority of twins stays unchanged until twin annihilation during the load reversal. The variations of measured average stresses across parents and twins are also investigated.

scholarly journals Ultrafast X-ray Diffraction Study of a Shock-Compressed Iron Meteorite above 100 GPa

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 567
Author(s):  
Sabrina Tecklenburg ◽  
Roberto Colina-Ruiz ◽  
Sovanndara Hok ◽  
Cynthia Bolme ◽  
Eric Galtier ◽  
...  
Keyword(s):  
Shock Compression ◽  
Iron Meteorite ◽  
Coarse Grained ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Natural Iron ◽  
First Time

Natural kamacite samples (Fe92.5Ni7.5) from a fragment of the Gibeon meteorite were studied as a proxy material for terrestrial cores to examine phase transition kinetics under shock compression for a range of different pressures up to 140 GPa. In situ time-resolved X-ray diffraction (XRD) data were collected of a body-centered cubic (bcc) kamacite section that transforms to the high-pressure hexagonal close-packed (hcp) phase with sub-nanosecond temporal resolution. The coarse-grained crystal of kamacite rapidly transformed to highly oriented crystallites of the hcp phase at maximum compression. The hcp phase persisted for as long as 9.5 ns following shock release. Comparing the c/a ratio with previous static and dynamic work on Fe and Fe-rich Fe-Ni alloys, it was found that some shots exhibit a larger than ideal c/a ratio, up to nearly 1.65. This work represents the first time-resolved laser shock compression structural study of a natural iron meteorite, relevant for understanding the dynamic material properties of metallic planetary bodies during impact events and Earth’s core elasticity.

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