Solid-State Phase Transformations Involving (Nb,Mo)2CrB2 Borides and (Nb,Ti)2CS Carbosulfides at the Grain Boundaries of Superalloy Inconel 718

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

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Toward a better understanding of chemical and microstructure heterogeneities inherited from solidification and solid state phase transformations in the Ti-48Al-2Cr-2Nb alloy

Matériaux & Techniques ◽

10.1051/mattech:2004005 ◽

2004 ◽

Vol 92 (1-2) ◽

pp. 39-50 ◽

Cited By ~ 5

Author(s):

M. Charpentier ◽

D. Daloz ◽

A. Hazotte ◽

E. Aeby-Gautier

Keyword(s):

Solid State ◽

Phase Transformations

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Wetting phase transition of grain boundaries and material performance of novel Inconel 718

Materials Letters ◽

10.1016/j.matlet.2021.129858 ◽

2021 ◽

pp. 129858

Author(s):

Ramkumar Thulasiram ◽

Selvakumar Mani ◽

Narayanan Ramaswamy ◽

Mohanraj Murugesan

Keyword(s):

Phase Transition ◽

Grain Boundaries ◽

Inconel 718

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Internal melt figures in ice by rapid adiabatic compression

Journal of Glaciology ◽

10.3189/s0022143000003890 ◽

1994 ◽

Vol 40 (134) ◽

pp. 132-134

Author(s):

R.E. Gagnon ◽

C. Tulk ◽

H. Kiefte

Keyword(s):

Phase Transformations ◽

Grain Boundaries ◽

Single Crystals ◽

Adiabatic Compression ◽

Air Bubbles ◽

Water Ice ◽

Deep Focus ◽

And Behavior ◽

First Time

AbstractSingle crystals and bicrystals of water ice have been adiabatically pressurized to produce, and clearly illustrate, two types of internal melt figures: (1) dendritic figures that grow from nucleation imperfections on the specimen’s surface, or from air bubbles at grain boundaries, into the ice as pressure is elevated; and (2) compression melt fractures, flat liquid-filled disks, that nucleate at imperfections in the crystal and grow with the application of pressure eventually to sprout dendritic fingers at the periphery. The transparency of the ice permitted visualization of the growth and behavior of the figures, and this could be an important tool in understanding the role of phase transformations in deep-focus earthquakes. Correlation between figure size and pressure is noted for the first time.

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