Journal ArticleDOI
A general mechanism of martensitic nucleation: Part I. General concepts and the FCC → HCP transformation
Gregory B. Olson,Morris Cohen +1 more
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In this paper, the stacking fault energy is shown to consist of both volume energy and surface energy contributions, and when the volume energy contribution is negative, the fault energy decreases with increasing fault thickness such that fault energy associated with the simultaneous dissociation of an appropriate group of dislocations can be zero or negative.Abstract:
Consideration of the martensitic nucleation process as a sequence of steps which take the particle from maximum to minimum coherency leads to the hypothesis that the first step in martensitic nucleation is faulting on planes of closest packing. It is further postulated that the faulting displacements are derived from an existing defect, while matrix constraints cause all subsequent processes to occur in such a way as to leave the fault plane unrotated, thus accounting for the observed general orientation relations. Using basic concepts of classical nucleation theory, the stacking fault energy is shown to consist of both volume energy and surface energy contributions. When the volume energy contribution is negative, the fault energy decreases with increasing fault thickness such that the fault energy associated with the simultaneous dissociation of an appropriate group of dislocations (e.g. a finite tilt boundary segment) can be zero or negative. This condition leads to the spontaneous formation of a martensitic embryo. For the specific case of the fcc → hcp martensitic transformation in Fe-Cr-Ni alloys, the defect necessary to account for spontaneous embryo formation at the observedM
s temperatures may consist of four or five properly spaced lattice dislocations. Such defects are considered to be consistent with the known sparseness of initial martensitic nucleation sites.read more
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Local Microstructural Stability and Hydrogen Embrittlement of Iron-Base FCC Alloys
Robert Fussik,Sebastian Weber +1 more
TL;DR: In this article, the influence of microsegregations on local properties of certain austenitic steels is investigated, which serve as a basis for calculated local properties which will be discussed in the context of hydrogen embrittlement.
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Fatigue-Crack Growth in the Superelastic Endovascular Stent Material Nitinol
A. L. Mckelvey,Robert O. Ritchie +1 more
TL;DR: In this article, a study of fatigue-crack propagation behavior in the superelastic alloy Nitinol has been conducted, where the material selected for this study has been heat treated such that it is supe-relastic at human body temperature and growth rates have been performed at 37°C on disc-shaped compact-tension samples.
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Stacking Fault Energy Based Alloy Screening for Hydrogen Compatibility
Paul J. Gibbs,P. D. Hough,Konrad Thürmer,Brian P. Somerday,C. San Marchi,Jonathan A. Zimmerman +5 more
TL;DR: In this paper, the intrinsic stacking fault energy (SFE) was used to compare the retention of tensile ductility of a range of stainless steels in the presence of hydrogen.
Journal ArticleDOI
Extraordinary stability of nano-twinned structure formed during phase transformation coupled with grain growth in electrodeposited Co–Ni alloys
TL;DR: In this paper, a hexagonal-close-packed (hcp) to face-centered-cubic (fcc) phase transformation coupled with grain growth in nanocrystalline Co-Ni alloys prepared by pulse electrodeposition was revealed.
Journal ArticleDOI
Effects of Strain Rate on the TRIP–TWIP Transition of an Austenitic Fe-18Mn-2Si-2Al Steel
Marcio Daniel Raposo,Mauro Martin,M. F. Giordana,Valeria de Los Angeles Fuster,Jorge Alberto Malarria +4 more
TL;DR: In this article, a fully austenitic Fe-18Mn-2Si-2Al transformation-induced plasticity (TRIP) steel was tensile tested from quasi-static to low-dynamic regime at three different strain rates: 4.7, 10−4, 1.3, and 8.3.
References
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The Determination of the Elastic Field of an Ellipsoidal Inclusion, and Related Problems
TL;DR: In this paper, it is shown that to answer several questions of physical or engineering interest, it is necessary to know only the relatively simple elastic field inside the ellipsoid.
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Theory of Dislocations
John Price Hirth,Jens Lothe +1 more
TL;DR: Dislocations in Isotropic Continua: Effects of Crystal Structure on Dislocations and Dislocation-Point-Defect Interactions at Finite temperatures.
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The scientific papers
TL;DR: Physical and psychosocial factors associated with psychostimulant use in a nationally representative sample of French adolescents: Specificities of cocaine, amphetamine, and ecstasy use are studied.
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The crystallography of martensite transformations II
J.S Bowles,J.K Mackenzie +1 more
TL;DR: In this paper, the total strain in a martensite transformation was derived from the orientation relationship and the component strains, together with the correspondence, and the dimensions of the initial and final structures.
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