The projection geometry of the field-ion image

Southworth, H.N.; Walls, John M.

doi:10.1016/0039-6028(78)90057-2

Cited by 24 publications

(9 citation statements)

References 7 publications

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“…For the emitter shapes considered in this study the closest standard projection was found to be the stereographic one. These results correlate closely with some recent measurements made by Southworth and Walls (1978), but are at variance with the widely quoted results obtained by Brandon (1964) who suggested that the use of the N = 2 projection would be more accurate. It has been shown analytically that not only are the ion trajectories independent of q and m, but they are also independent of the potential difference V between tip and screen.…”

Section: Discussionsupporting

confidence: 91%

Ion trajectories in the field-ion microscope

Smith¹,

Walls²

1978

J. Phys. D: Appl. Phys.

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The trajectories of the imaging ions in the field-ion microscope have been determined for hyperboloidal and paraboloidal emitter shapes. The shape of the trajectories has been shown to be independent of the potential difference between the emitter and the microscope screen and the charge-to-mass ratio of the ion. It has also been found to vary little with tip-to-screen distance and nose curvature. The stereographic projection is found to be in good agreement with the calculated results.

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Section: Discussionsupporting

confidence: 91%

Ion trajectories in the field-ion microscope

Smith¹,

Walls²

1978

J. Phys. D: Appl. Phys.

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“…[327][328][329][330] The geometry of the specimen provides the projection with a magnification in the range of 10 6 , so interatomic distances can in principle be resolved. [331] Time-control over the field evaporation process is gained by either superimposing high-voltage pulses [332] of short laser pulses [333][334][335] onto a direct current (DC) voltage. Knowing when the ion is generated and when it strikes the detector allows for performing time-of-flight mass spectrometry, thereby enabling the identification of the elemental nature of each collected ion.…”

Section: B Atom Probe Tomography For the Investigation Of Advanced Smentioning

confidence: 99%

Current Challenges and Opportunities in Microstructure-Related Properties of Advanced High-Strength Steels

Raabe

Sun

Silva

et al. 2020

Metall Mater Trans A

137

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This is a viewpoint paper on recent progress in the understanding of the microstructure–property relations of advanced high-strength steels (AHSS). These alloys constitute a class of high-strength, formable steels that are designed mainly as sheet products for the transportation sector. AHSS have often very complex and hierarchical microstructures consisting of ferrite, austenite, bainite, or martensite matrix or of duplex or even multiphase mixtures of these constituents, sometimes enriched with precipitates. This complexity makes it challenging to establish reliable and mechanism-based microstructure–property relationships. A number of excellent studies already exist about the different types of AHSS (such as dual-phase steels, complex phase steels, transformation-induced plasticity steels, twinning-induced plasticity steels, bainitic steels, quenching and partitioning steels, press hardening steels, etc.) and several overviews appeared in which their engineering features related to mechanical properties and forming were discussed. This article reviews recent progress in the understanding of microstructures and alloy design in this field, placing particular attention on the deformation and strain hardening mechanisms of Mn-containing steels that utilize complex dislocation substructures, nanoscale precipitation patterns, deformation-driven transformation, and twinning effects. Recent developments on microalloyed nanoprecipitation hardened and press hardening steels are also reviewed. Besides providing a critical discussion of their microstructures and properties, vital features such as their resistance to hydrogen embrittlement and damage formation are also evaluated. We also present latest progress in advanced characterization and modeling techniques applied to AHSS. Finally, emerging topics such as machine learning, through-process simulation, and additive manufacturing of AHSS are discussed. The aim of this viewpoint is to identify similarities in the deformation and damage mechanisms among these various types of advanced steels and to use these observations for their further development and maturation.

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“…Then, the position of the surface of the sample ( x , y ) are deduced from the ion's impact on the detector ( X , Y ), thanks to a projection law (Southworth & Walls, 1978), equation (12):…”

Section: Simulation Results and Discussionmentioning

confidence: 99%