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

<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&#160; 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>

Download Full-text

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

Metals ◽

10.3390/met10121619 ◽

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.

Download Full-text

In-situ X-ray diffraction during tensile deformation of ultrafine-grained copper using synchrotron radiation

Philosophical Magazine Letters ◽

10.1080/09500839.2016.1218563 ◽

2016 ◽

Vol 96 (8) ◽

pp. 294-304 ◽

Cited By ~ 10

Author(s):

Yoji Miyajima ◽

Satoshi Okubo ◽

Tomotaka Miyazawa ◽

Hiroki Adachi ◽

Toshiyuki Fujii

Keyword(s):

Synchrotron Radiation ◽

Tensile Deformation ◽

X Ray Diffraction ◽

X Ray ◽

Ultrafine Grained

Download Full-text

Tensile Deformation of Ultrafine-Grained Fe-Mn-Al-Ni-C Alloy Studied by In Situ Synchrotron Radiation X-ray Diffraction

Crystals ◽

10.3390/cryst10121115 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1115

Author(s):

Si Gao ◽

Takuma Yoshimura ◽

Wenqi Mao ◽

Yu Bai ◽

Wu Gong ◽

...

Keyword(s):

Synchrotron Radiation ◽

Tensile Deformation ◽

Tensile Ductility ◽

High Strength ◽

X Ray Diffraction ◽

Premature Failure ◽

X Ray ◽

Intermetallic Particles ◽

Ultrafine Grained

Intermetallic compounds are usually considered as deleterious phase in alloy designing and processing since their brittleness leads to poor ductility and premature failure during deformation of the alloys. However, several studies recently found that some alloys containing large amounts of NiAl-type intermetallic particles exhibited not only high strength but also good tensile ductility. To clarify the role of the intermetallic particles in the excellent tensile properties of such alloys, the tensile deformation behavior of an ultrafine-grained Fe-Mn-Al-Ni-C alloy containing austenite matrix and B2 intermetallic particles was investigated by using in situ synchrotron radiation X-ray diffraction in the present study. The elastic stress partitioning behavior of two constituent phases during tensile deformation were quantitively measured, and it was suggested that B2 particles played an important role in the high strength and large tensile ductility of the material.

Download Full-text

In situsynchrotron X-ray diffraction analysis of deformation behaviour in Ti–Ni-based thin films

Journal of Synchrotron Radiation ◽

10.1107/s1600577514021031 ◽

2015 ◽

Vol 22 (1) ◽

pp. 34-41

Author(s):

Hong Wang ◽

Guangai Sun ◽

Xiaolin Wang ◽

Bo Chen ◽

Xiaotao Zu ◽

...

Keyword(s):

Thin Films ◽

Deformation Behaviour ◽

Deformation Mechanisms ◽

X Ray Diffraction ◽

X Ray ◽

Thermal Expansion Coefficients ◽

Post Annealing ◽

Expansion Coefficients ◽

Martensitic Variants

Deformation mechanisms of as-deposited and post-annealed Ti50.2Ni49.6, Ti50.3Ni46.2Cu3.5and Ti48.5Ni40.8Cu7.5thin films were investigated using thein situsynchrotron X-ray diffraction technique. Results showed that initial crystalline phases determined the deformation mechanisms of all the films during tensile loading. For the films dominated by monoclinic martensites (B19′), tensile stress induced the detwinning of 〈011〉 type-II twins and resulted in the preferred orientations of (002)B19′parallel to the loading direction (∥ LD) and (020)B19′perpendicular to the LD (⊥ LD). For the films dominated by austenite (B2), the austenite directly transformed into martensitic variants (B19′) with preferred orientations of (002)B19′ ∥ LD and (020)B19′ ⊥ LD. For the Ti50.3Ni46.2Cu3.5and Ti48.1Ni40.8Cu7.5films, martensitic transformation temperatures decreased apparently after post-annealing because of the large thermal stress generated in the films due to the large differences in thermal expansion coefficients between the film and substrate.

Download Full-text