Nuggets
See the historic VG FIM100 Atom Probe at the Field Museum
NUCAPT's historic Vacuum Generator VG FIM100 atom probe field ion microscope (APFIM) is exhibited at the Field Museum of Natural History, Chicago, since April 2021. Prominently featured is the Poschenrieder lens with the slightly angled flight tube at the left top that bestowed this instrument with excellent mass resolution. We will provide more information how to best pay a visit as we gather details.
VG100 atom probe at the Field Museum.
The FIM100 APFIM had previously been exhibited at Chicago's O'Hare airport, Gate B11 (2016-2017), Chicago's Museum of Science and Industry (2015-2016) as reported in this article in the Chicago Tribune, and the Harold Washington Library of Chicago's Public Library system (2019-2021).
Atom Probe Tomography WORKSHOP
At NUCAPT's APT workshop Oct 22/23, 2019, offering training in the IVAS® APT data visualization and evaluation software, presentations of APT to a variety of materials analyses, and new techniques for correlative investigations that include APT, attendees were also invited to visit the NUCAPT laboratory and see one of the worldwide first installations of the CAMECA® AP Suite 6 in action.
Attendees at our APT workshop exploring atom probe data analysis in AP Suite 6. Photo credit: Dr. Keith Knipling
The info for our workshop, the program, and a photo, are also displayed on the atomprobe.com website.
Atom Probe Tomography WORKSHOP
All interested in APT are invited to our Workshop with IVAS training and Application Talks. Please register here by October 15, 2019.
Day 1, Tuesday Oct 22
8:30 AM - 5:00 PM
• Practical Training in APT Data Analysis using CAMECA IVAS® 3.8 software
• Location: Bodeen Design Laboratory, Room C115, Tech Institute, 2145 Sheridan Rd
Day 2, Wednesday Oct 23
8:30 AM - 12:00 PM
• New Developments in APT
• Location: Room B211 (Mechanical Engineering Conference Room, Tech Institute, 2145 Sheridan Rd
12:55 PM - 1:25 PM
• APT Open House: Come see our LEAP5000 XS, ask questions, and discuss your research applications
• Location: Cook Hall #1082-1086 (NUCAPT Laboratory, Cook Hall, 2220 Campus Drive, Evanston, IL 60208
1:30 AM - 5:00 PM
• Application Talks, and Special Topics
• Location: Mudd Hall #3514 (Computer Science Department), 2233 Tech Drive Evanston, IL 60208
Please register here by October 15, 2019.
A group of enthusiastic atom-probe tomographers took their first laps with the new LEAP5000XS today, Nov 2, 2017. Thanks for stopping by!
Photo credit: Dr. Jason Sebastian
Prof. D. Isheim demonstrated and explained the new features and GUI design elements that now can be used with the LEAP5000XS in an open-house style question and answer session. A very big thank you to the crew from the manufacturer, CAMECA, and specifically to the installation engineers Timothy Kaltenbach, Ryan Brecke and Jiwan Kim who got us up and running in an amazingly short period and ahead of schedule!
LEAP5000XS upgrade: The upgrade of NUCAPT's LEAP to the newest CAMECA LEAP5000XS configuration has been completed.
Photo credit: D. Isheim
This digital field-ion micrograph was taken on October 31, 2017, with the new CAMECA LEAP5000XS. The mircograph shows individual tungsten atoms (each bright spot is the image of a single atom) at the end of a sharp tungsten tip. Imaging conditions: 5.3 kV, 50K, 3 x 10E-8 Torr He.
LEAP5000XS upgrade: NUCAPT's LEAP is currently being upgraded with the newest CAMECA LEAP5000XS technology.
Photo credit: D. Isheim
We are very excited to very shortly have a CAMECA LEAP5000XS available to continue our atomic-scale imaging and analysis,featuring a single-atom position-sensitive time-of-flight detector with 80% detection efficiency, compared to 50% efficiency with the old LEAP4000XSi instrument we operated before
The historic VG FIM100 atom-probe field-ion microscope (APFIM) was on display in Terminal 1 at O'Hare Airport in the concourse opposite gate B12 from May 2016 through October 2017. It was moved to O'Hare Airport to spend part of its retirement days among applications of the high-performance structural and areo-space materials it helped develop.
Photo credit: Dr. Nhon Vo
NUCAPT had originally donated the VG FIM100 APFIM to Chicago's Museum of Science and Industry where it anchored the exhibition Materials Science at MSI (press kit). The Chicago Tribune ran an article about the exhibition "Materials Science" at the MSI on March 25, 2015.
NUCAPT donated the VG FIM100 atom-probe field-ion microscope (APFIM) to Chicago's Museum of Science and Industry. It is now on display and anchoring the exhibition Materials Science at MSI (press kit):
Photo credit: Randall Mattheis
The VG FIM100 is now on display in the exhibition "Materials Science" at Chicago's MSI. The Chicago Tribune ran an article on March 25, 2015.
TEM and three-dimensional Atom-Probe reconstruction of a Si nanowire catalyzed with Aluminum. This work was featured in [Nature] http://www.nature.com/nature/journal/v496/n7443/full/nature11999.html.
Structure and three-dimensional map of Al-catalysed Si
nanowires. a, High-resolution cross-sectional TEMimage (left) displaying the
interface between the catalyst particle and the nanowire. The right panel
exhibits a close-up image of the interface (top), the fast Fourier transformof the
image (middle), and the corresponding colour-filtered image (bottom, Al and
Si regions correspond to red and blue regions, respectively) indicating that the
interface is epitaxial. b, Three-dimensional APT atom-by-atom map of a
nanowire grown at 410 uC. For the sake of clarity, only a limited number of
atoms is displayed (2.53104 atoms of each element). Inset, a cross-sectional
TEM image of an identical Si nanowire (scale bar, 40 nm). c, Si 50 at.%
isoconcentration surface of an 80-nm-long segment of a nanowire determined
by analysing a three-dimensional atom-probe tomographic reconstruction: left,
side view; right, top view.
Art fair submission: Technicolor Asteroid Belt
- (Courtesy: Liza Plotnikov)
(Courtesy: Liza Plotnikov)
Transmission Electron Microscopy (TEM) image of a Ni3Al precipitate in a Ni-rich matrix. As the alloy is aged, the precipitates will evolve from a spherical morphology to a cuboidal morphology. TEM and LEAP are used to study the temporal evolution of this alloy.
(Courtesy: Liza Plotnikov)
Three-dimensional LEAP tomographic reconstructions of Al–0.06 Sc–0.02 Tb and Al–0.06 Sc–0.02 Tm (at.%) aged for: (a) 10 minutes, and (b) 24 hours at 300 °C. Each reconstruction is divided into three sections, with Sc atoms only displayed in the leftmost section, rare earth (RE) atoms only displayed in the center section, and both Sc and RE atoms displayed in the rightmost section. After 10 minutes aging time, nanometer-sized RE-rich Al3(RE1-xScx) precipitates have formed. With continued aging to 24 hours, a core-shell structure is evident in the precipitates, with a RE-rich core surrounded by a Sc-rich shell.
(Courtesy: Matt Krug)
A proxigram obtained from a LEAP tomographic dataset of a dilute Al-Sc-Lu alloy which has been aged at 300 deg C. Nanometer-sized Al3(Sc1-xLux) precipitates are exploited as a strengthening phase. This proxigram quantifies the core/shell structure which develops in the precipitates, with Lu segregating to the center of the precipitates and Sc forming a shell around the core.
(Courtesy: Matt Krug)
The edge-to-edge interprecipitate distance is an important quantity for many physical properties, including the yield strength, conductivity, and coarsening behavior. Because LEAP tomography is able to analyze a large number of precipitates, it can be used to find the interprecipitate distance distribution. The precipitates in this Fe-Cu alloy are fit as ellipsoids and the distances between them are calculated, as described in Direct Measurement of 2-Dimensional and 3-Dimensional Interprecipitate Distance Distributions from Atom-Probe Tomographic Reconstructions
(Courtesy: Richard Karnesky and Dieter Isheim)
This LEAP tomography data set is from a blast resistant steel which has been aged at 550°C and 450°C. Nanosize Cu precipitates are one of the major contributors to the strength of the steel, and as such it is important to understand their nucleation, growth, and coarsening behavior. Heterogeneous nucleation, which is seen here along a grain boundary, changes the behavior from what would be predicted by models for purely homogeneous nucleation. The red represents a 5 at% Cu isoconcentration surface.(Courtesy: Mike Mulholland)
The figure displays a 3-D reconstruction of a Ni-6.24 Al-9.64 Cr at.% alloy aged at 873 K for 2 hours, which contains 72 million atoms and 1150 γ’-precipitates. The number density of precipitates is (7.15 ± 0.21) x 1023 m-3 , with an average radius of (1.11±0.26) nm and an average precipitate edge-to-edge spacing of (3.66±1.33) nm. The data was recorded employing a pulse repetition rate of 200 kHz, a pulse energy of 0.6 nJ, an effective pulse fraction of 20%, a specimen temperature of 40 K, and the target evaporation rate ranged from 0.2 to 7% over the length of the specimen. (Courtesy: Chris Booth-Morrison and Yang Zhou)
The NUCAPT LEAP tomograph is upgraded with a larger detector, faster pulser, and digital FIM. (L-to-R: Dieter Isheim, Aniruddha Biswas, Mark Levesque. Photo credit: Richard Karnesky)
Left: Best-fit ellipsoids to coagulated precipitates in 3DAP data for a Ni-Al-Cr alloy. The coagulation coarsening mechanism is discussed in a recent Nature Materials article and the best-fit ellipsoid algorithm and orientational dependence are described in another recently accepted article
Below: Inverse pole figure of ellipsoid orientation, showing a <110> preference.
Lattice kinetic Monte Carlo simulation by Dr. Zugang Mao showing coagulation and coalescense of L12 ordered precipitates in a model Ni-Al-Cr superalloy. This coarsening mechanism is discussed in The mechanism of morphogenesis in a phase separating concentrated multi-component alloy.
Al-Sc-Er alloy, with Sc atoms in purple and Er atoms in gold. The isoconcentration surfaces show that Er partitions to the core of the precipitate and Sc partitions to the precipitate shell. This is described further in Effects of Substituting Rare-Earth Elements for Scandium in a Precipitation-Strengthened Al 0.08 at.% Sc Alloy by Rick and Marsha.
NUCAPT has donated their VG100 1DAP/FIM to the Museum of Science and Industry. It will become part of a nanotechnology exhibit they are building. Photo credit: Thom Burdsall.
Heterogeneous nucleation of copper precipitates on a large carbide precipitate in a blast resistant steel. The black dots represent carbon atoms and the red surfaces are 10 at% copper isoconcentration surfaces. Knowledge of the interactions of the different kinds of precipitates in this alloy is important for determining the effects of internal structure on the mechanical properties. Note the heavily distorted nature of the precipitates that nucleated on the carbide, which indicates their nucleation mode. The box dimensions are 66 nm x 68 nm x 149 nm.
The study of the surface chemistry of high-purity Nb is extremely important for the advancement of superconducting radio-frequency (SRF) cavities. The figure displays the 3-D reconstruction of Nb oxide on the surface of Nb. The reconstruction contains 300,000 atoms in 51 x 53 x 14 nm3 box. Nb atoms are in magenta, O atoms in cyan.
γ’-Ni3(Al,Cr) precipitates such as the one imaged above are responsible for the high-temperature strength of Ni-Based Superalloys. The spheroidal γ’-precipitate of radius ca. 9 nm is delineated from the γ-matrix phase by a 10.5 at.% aluminum isoconcentration surface. {110} planes are clearly defined by aluminum (red) and chromium atoms (blue), while Ni atoms are omitted for clarity. This image was obtained using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments
A 3-D visual reconstruction of a grain boundary found in an Fe-Cu multicomponent steel alloy specimen analyzed using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments. The specimen was solution treated for 40 minutes at 900 degrees Celsius and quenched in water at 25 degrees Celsius. An enhanced view of individual C, B, P, and S ions are seen in the bottom right of the figure delineating the grain boundary.
A 3-D visual reconstruction of two nanoscale precipitates found in an Fe-Cu multicomponent steel alloy specimen analyzed using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments. The specimen was aged for 1024-hours at 500 degrees Celsius after solution treatment for 40 minutes at 900 degrees Celsius. The isoconcentration surfaces are at 12.0 at.% Ni - 9.5 Al - 3.0 Mn. An enhanced view of individual Cu (in the precipitate cut by the surface of the reconstruction volume) and Fe atoms are displayed delineating both the precipitate core and matrix. The remaining solute atoms (Ni, Al, Si, and Mn) atoms are not shown for clarity.
A nanoscale precipitate found in an Al-Sc-Yb alloy specimen analyzed using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments. The <200> planes (spacing ~0.2nm) in the crystalline lattice of the bulk Al structure are seen in ordered rows (green points). The <100> planes (~spacing 0.4 nm) in the precipitate are also clearly visible.
This nugget was featured in Imago's 2006 Calendar.
This LEAP tomography data set is from a dilute Al-Sc-Yb alloy which has been aged at 300°C. Nanosize Al3(Sc1-xYbx) precipitates (L12 structure) improve the strength and creep resistance of Al. Yb segregates to the center of the precipitates while the Sc segregates around the Yb core. The green spheres represent Yb atoms and the blue spheres represent Sc. Blue and green surfaces represent isoconcentration surfaces of Sc and Yb. Al atoms omitted for clarity.
This nugget was featured in Imago's March newsletter.
Catalyst nanowire interface in three dimensions. (a) 1-nm-thick slices through the nanowire over the region defined by the white bar in b. The diameter of the slices is 10 nm. (b) A 14 × 14 × 23 nm3 reconstruction of an InAs nanowire tip showing Au catalyst particle at the top. (c) One-dimensional composition profile plotted along the growth axis and through the catalyst/nanowire interface. The plotted composition is a radially averaged value within a 4-nm-diameter cylinder centered in the middle of the nanowire. From Local-Electrode Atom-Probe tomography by Danny Perea which appears in Three-Dimensional Nanoscale Composition Mapping of Semiconductor Nanowires.
Nanometer-sized copper-rich precipitates are an important strengthening element in high-strength low-alloy and low-carbon steels. This 3D atom-probe tomographic reconstruction displays copper-rich precipitates in NUCu-100 steel, designed at Northwestern University to achieve a ultimate tensile strength of 100 ksi (700MPa), for more details see 'Co-precipitation of Copper and Niobium Carbide in a Low Carbon Steel', M.S. Gagliano, PhD Thesis, Northwestern University, 2002. The spatial distributions of individual Cu, Ni, Si, Al, and Mn atoms are shown in a reconstructed volume 2 nm in thickness and with a lateral cross-section of 15 x 14 nm2. It is seen qualitatively that Ni, Al, and Mn are enriched at the locations of the Cu-rich precipitates. For quantitative information on the copper-rich precipitates and the enrichment of Ni, Al, and Mn see 'Interfacial segregation at Cu-rich precipitates in a high-strength low-carbon steel studied on a sub-nanometer scale', D. Isheim, M.S. Gagliano, M.E. Fine, and D.N. Seidman, Acta Materialia Vol. 54(2006) pp. 841-849.
A challenge for castable Al alloys is that few elements exhibit appreciable solubility in Al. Hence, the volume fraction of any precipitated phases is low (typically less than 1 vol.%). This contrasts from the Ni-based alloys, in which Al and Ti exhibit high solubility in Ni, leading to large volume fractions (usually exceeding 50%).
Analogous to γ' in the Al system are the trialuminides (Al3M, where M is a transition element). In order to achieve superalloy-like performance in Al, the precipitated Al3M must be very small, of the order of nm. Rick and Marsha are addressing this with ternary and quaternary additions to Al3Sc. Keith is investigating Al3Zr-based alloys.
Transmission-electron micrograph of a 3DAP tomograph tip. The coherency contrast comes from nano-scale Al3Sc precipitates in Al (after aging at 300° C for 5 hours). These fine precipitates lead to high strength at ambient and elevated temperatures. Marsha van Dalen and Richard Karnesky are introducing ternary and quarternary alloying additions to further improve mechanical properties and coarsening resistance.
From Emmanuelle Marquis's Ph.D. Thesis.
Within a model Ni-5.2 Al-14.2 Cr at. % superalloy, γ'-precipitation is first detected with atom-probe tomography (APT) after aging for 600 s at 873 K. Each dot within this thin 12 x 5 x 2 nm3 slice from an APT reconstructed volume represents an atom, positioned with sub-nanometer sensitivity, from a specimen aged at 600 s and analyzed along the [001]-direction. The Al and Cr atoms, displayed with red and blue dots, are enlarged in the nanometer-sized γ'-precipitate (R = 0.8 nm) to emphasize the resolution of {002} superlattice planes (d200=0.356 nm) associated with the L12-ordered γ'-phase. The interface between the γ'-precipitate and γ-matrix is delineated clearly with a red 9 at. % Al isoconcentration surface. Approximately, 2/3 of the γ'-precipitate volume is imaged above, and the full precipitate contains 109 detected atoms: 78 Ni (not displayed), 21 Al, and 10 Cr.
A field-ion micrograph displaying platelet-shaped molybdenum nitride precipitates with {100}-habit planes in an internally nitrided Fe-2at.% Mo-0.5at.%Sn alloy. Each bright dot represents a single atom in the surface of the FIM tip. The lines of bright dots are the traces of nitride platelets cutting through the approximately hemispherical surface of the apex of the FIM tip, resulting in three sets of lines representing the three {100} habit plane variants. The two concentric circles below the center of the micrograph are the two atomic layers of a platelet tangential to the tip surface, at a (100) pole.
Within a model Ni-5.2 Al-14.2 Cr at. % superalloy, γ'-precipitation is first detected with atom-probe tomography (APT) after aging for 600 s at 873 K. Each dot within this thin 12 x 5 x 2 nm3 slice from an APT reconstructed volume represents an atom, positioned with sub-nanometer sensitivity, from a specimen aged at 600 s and analyzed along the [001]-direction. The Al and Cr atoms, displayed with red and blue dots, are enlarged in the nanometer-sized γ'-precipitate (R = 0.8 nm) to emphasize the resolution of {002} superlattice planes (d200=0.356 nm) associated with the L12-ordered γ'-phase. The interface between the γ'-precipitate and γ-matrix is delineated clearly with a red 9 at. % Al isoconcentration surface. Approximately, 2/3 of the γ'-precipitate volume is imaged above, and the full precipitate contains 109 detected atoms: 78 Ni (not displayed), 21 Al, and 10 Cr.
Transmission-electron micrograph of a 3DAP tomograph tip. The coherency contrast comes from nano-scale Al3Sc precipitates in Al (after aging at 300° C for 5 hours). These fine precipitates lead to high strength at ambient and elevated temperatures. Marsha van Dalen and Richard Karnesky are introducing ternary and quarternary alloying additions to further improve mechanical properties and coarsening resistance.
From Emmanuelle Marquis's Ph.D. Thesis.
A challenge for castable Al alloys is that few elements exhibit appreciable solubility in Al. Hence, the volume fraction of any precipitated phases is low (typically less than 1 vol.%). This contrasts from the Ni-based alloys, in which Al and Ti exhibit high solubility in Ni, leading to large volume fractions (usually exceeding 50%).
Analogous to γ' in the Al system are the trialuminides (Al3M, where M is a transition element). In order to achieve superalloy-like performance in Al, the precipitated Al3M must be very small, of the order of nm. Rick and Marsha are addressing this with ternary and quaternary additions to Al3Sc. Keith is investigating Al3Zr-based alloys.
Nanometer-sized copper-rich precipitates are an important strengthening element in high-strength low-alloy and low-carbon steels. This 3D atom-probe tomographic reconstruction displays copper-rich precipitates in NUCu-100 steel, designed at Northwestern University to achieve a ultimate tensile strength of 100 ksi (700MPa), for more details see 'Co-precipitation of Copper and Niobium Carbide in a Low Carbon Steel', M.S. Gagliano, PhD Thesis, Northwestern University, 2002. The spatial distributions of individual Cu, Ni, Si, Al, and Mn atoms are shown in a reconstructed volume 2 nm in thickness and with a lateral cross-section of 15 x 14 nm2. It is seen qualitatively that Ni, Al, and Mn are enriched at the locations of the Cu-rich precipitates. For quantitative information on the copper-rich precipitates and the enrichment of Ni, Al, and Mn see 'Interfacial segregation at Cu-rich precipitates in a high-strength low-carbon steel studied on a sub-nanometer scale', D. Isheim, M.S. Gagliano, M.E. Fine, and D.N. Seidman, Acta Materialia Vol. 54(2006) pp. 841-849.
This nugget was featured in Imago's March newsletter.
Catalyst nanowire interface in three dimensions. (a) 1-nm-thick slices through the nanowire over the region defined by the white bar in b. The diameter of the slices is 10 nm. (b) A 14 × 14 × 23 nm3 reconstruction of an InAs nanowire tip showing Au catalyst particle at the top. (c) One-dimensional composition profile plotted along the growth axis and through the catalyst/nanowire interface. The plotted composition is a radially averaged value within a 4-nm-diameter cylinder centered in the middle of the nanowire. From Local-Electrode Atom-Probe tomography by Danny Perea which appears in Three-Dimensional Nanoscale Composition Mapping of Semiconductor Nanowires.
This nugget was featured in Imago's 2006 Calendar.
This LEAP tomography data set is from a dilute Al-Sc-Yb alloy which has been aged at 300°C. Nanosize Al3(Sc1-xYbx) precipitates (L12 structure) improve the strength and creep resistance of Al. Yb segregates to the center of the precipitates while the Sc segregates around the Yb core. The green spheres represent Yb atoms and the blue spheres represent Sc. Blue and green surfaces represent isoconcentration surfaces of Sc and Yb. Al atoms omitted for clarity.
A nanoscale precipitate found in an Al-Sc-Yb alloy specimen analyzed using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments. The <200> planes (spacing ~0.2nm) in the crystalline lattice of the bulk Al structure are seen in ordered rows (green points). The <100> planes (~spacing 0.4 nm) in the precipitate are also clearly visible.
A 3-D visual reconstruction of two nanoscale precipitates found in an Fe-Cu multicomponent steel alloy specimen analyzed using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments. The specimen was aged for 1024-hours at 500 degrees Celsius after solution treatment for 40 minutes at 900 degrees Celsius. The isoconcentration surfaces are at 12.0 at.% Ni - 9.5 Al - 3.0 Mn. An enhanced view of individual Cu (in the precipitate cut by the surface of the reconstruction volume) and Fe atoms are displayed delineating both the precipitate core and matrix. The remaining solute atoms (Ni, Al, Si, and Mn) atoms are not shown for clarity.
A 3-D visual reconstruction of a grain boundary found in an Fe-Cu multicomponent steel alloy specimen analyzed using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments. The specimen was solution treated for 40 minutes at 900 degrees Celsius and quenched in water at 25 degrees Celsius. An enhanced view of individual C, B, P, and S ions are seen in the bottom right of the figure delineating the grain boundary.
γ’-Ni3(Al,Cr) precipitates such as the one imaged above are responsible for the high-temperature strength of Ni-Based Superalloys. The spheroidal γ’-precipitate of radius ca. 9 nm is delineated from the γ-matrix phase by a 10.5 at.% aluminum isoconcentration surface. {110} planes are clearly defined by aluminum (red) and chromium atoms (blue), while Ni atoms are omitted for clarity. This image was obtained using a Local Electrode Atom Probe (LEAP®) from Imago Scientific Instruments
The study of the surface chemistry of high-purity Nb is extremely important for the advancement of superconducting radio-frequency (SRF) cavities. The figure displays the 3-D reconstruction of Nb oxide on the surface of Nb. The reconstruction contains 300,000 atoms in 51 x 53 x 14 nm3 box. Nb atoms are in magenta, O atoms in cyan.
Heterogeneous nucleation of copper precipitates on a large carbide precipitate in a blast resistant steel. The black dots represent carbon atoms and the red surfaces are 10 at% copper isoconcentration surfaces. Knowledge of the interactions of the different kinds of precipitates in this alloy is important for determining the effects of internal structure on the mechanical properties. Note the heavily distorted nature of the precipitates that nucleated on the carbide, which indicates their nucleation mode. The box dimensions are 66 nm x 68 nm x 149 nm.
NUCAPT has donated their VG100 1DAP/FIM to the Museum of Science and Industry. It will become part of a nanotechnology exhibit they are building. Photo credit: Thom Burdsall.
Al-Sc-Er alloy, with Sc atoms in purple and Er atoms in gold. The isoconcentration surfaces show that Er partitions to the core of the precipitate and Sc partitions to the precipitate shell. This is described further in Effects of Substituting Rare-Earth Elements for Scandium in a Precipitation-Strengthened Al 0.08 at.% Sc Alloy by Rick and Marsha.
Lattice kinetic Monte Carlo simulation by Dr. Zugang Mao showing coagulation and coalescense of L12 ordered precipitates in a model Ni-Al-Cr superalloy. This coarsening mechanism is discussed in The mechanism of morphogenesis in a phase separating concentrated multi-component alloy.
Left: Best-fit ellipsoids to coagulated precipitates in 3DAP data for a Ni-Al-Cr alloy. The coagulation coarsening mechanism is discussed in a recent Nature Materials article and the best-fit ellipsoid algorithm and orientational dependence are described in another recently accepted article
Below: Inverse pole figure of ellipsoid orientation, showing a <110> preference.
The NUCAPT LEAP tomograph is upgraded with a larger detector, faster pulser, and digital FIM. (L-to-R: Dieter Isheim, Aniruddha Biswas, Mark Levesque. Photo credit: Richard Karnesky)
The figure displays a 3-D reconstruction of a Ni-6.24 Al-9.64 Cr at.% alloy aged at 873 K for 2 hours, which contains 72 million atoms and 1150 γ’-precipitates. The number density of precipitates is (7.15 ± 0.21) x 1023 m-3 , with an average radius of (1.11±0.26) nm and an average precipitate edge-to-edge spacing of (3.66±1.33) nm. The data was recorded employing a pulse repetition rate of 200 kHz, a pulse energy of 0.6 nJ, an effective pulse fraction of 20%, a specimen temperature of 40 K, and the target evaporation rate ranged from 0.2 to 7% over the length of the specimen. (Courtesy: Chris Booth-Morrison and Yang Zhou)
This LEAP tomography data set is from a blast resistant steel which has been aged at 550°C and 450°C. Nanosize Cu precipitates are one of the major contributors to the strength of the steel, and as such it is important to understand their nucleation, growth, and coarsening behavior. Heterogeneous nucleation, which is seen here along a grain boundary, changes the behavior from what would be predicted by models for purely homogeneous nucleation. The red represents a 5 at% Cu isoconcentration surface.(Courtesy: Mike Mulholland)
The edge-to-edge interprecipitate distance is an important quantity for many physical properties, including the yield strength, conductivity, and coarsening behavior. Because LEAP tomography is able to analyze a large number of precipitates, it can be used to find the interprecipitate distance distribution. The precipitates in this Fe-Cu alloy are fit as ellipsoids and the distances between them are calculated, as described in Direct Measurement of 2-Dimensional and 3-Dimensional Interprecipitate Distance Distributions from Atom-Probe Tomographic Reconstructions
(Courtesy: Richard Karnesky and Dieter Isheim)
A proxigram obtained from a LEAP tomographic dataset of a dilute Al-Sc-Lu alloy which has been aged at 300 deg C. Nanometer-sized Al3(Sc1-xLux) precipitates are exploited as a strengthening phase. This proxigram quantifies the core/shell structure which develops in the precipitates, with Lu segregating to the center of the precipitates and Sc forming a shell around the core.
(Courtesy: Matt Krug)
Three-dimensional LEAP tomographic reconstructions of Al–0.06 Sc–0.02 Tb and Al–0.06 Sc–0.02 Tm (at.%) aged for: (a) 10 minutes, and (b) 24 hours at 300 °C. Each reconstruction is divided into three sections, with Sc atoms only displayed in the leftmost section, rare earth (RE) atoms only displayed in the center section, and both Sc and RE atoms displayed in the rightmost section. After 10 minutes aging time, nanometer-sized RE-rich Al3(RE1-xScx) precipitates have formed. With continued aging to 24 hours, a core-shell structure is evident in the precipitates, with a RE-rich core surrounded by a Sc-rich shell.
(Courtesy: Matt Krug)
(Courtesy: Liza Plotnikov)
Art fair submission: Technicolor Asteroid Belt
- (Courtesy: Liza Plotnikov)
TEM and three-dimensional Atom-Probe reconstruction of a Si nanowire catalyzed with Aluminum. This work was featured in [Nature] http://www.nature.com/nature/journal/v496/n7443/full/nature11999.html.
Structure and three-dimensional map of Al-catalysed Si
nanowires. a, High-resolution cross-sectional TEMimage (left) displaying the
interface between the catalyst particle and the nanowire. The right panel
exhibits a close-up image of the interface (top), the fast Fourier transformof the
image (middle), and the corresponding colour-filtered image (bottom, Al and
Si regions correspond to red and blue regions, respectively) indicating that the
interface is epitaxial. b, Three-dimensional APT atom-by-atom map of a
nanowire grown at 410 uC. For the sake of clarity, only a limited number of
atoms is displayed (2.53104 atoms of each element). Inset, a cross-sectional
TEM image of an identical Si nanowire (scale bar, 40 nm). c, Si 50 at.%
isoconcentration surface of an 80-nm-long segment of a nanowire determined
by analysing a three-dimensional atom-probe tomographic reconstruction: left,
side view; right, top view.
NUCAPT donated the VG FIM100 atom-probe field-ion microscope (APFIM) to Chicago's Museum of Science and Industry. It is now on display and anchoring the exhibition Materials Science at MSI (press kit):
Photo credit: Randall Mattheis
The VG FIM100 is now on display in the exhibition "Materials Science" at Chicago's MSI. The Chicago Tribune ran an article on March 25, 2015.
The historic VG FIM100 atom-probe field-ion microscope (APFIM) was on display in Terminal 1 at O'Hare Airport in the concourse opposite gate B12 from May 2016 through October 2017. It was moved to O'Hare Airport to spend part of its retirement days among applications of the high-performance structural and areo-space materials it helped develop.
Photo credit: Dr. Nhon Vo
NUCAPT had originally donated the VG FIM100 APFIM to Chicago's Museum of Science and Industry where it anchored the exhibition Materials Science at MSI (press kit). The Chicago Tribune ran an article about the exhibition "Materials Science" at the MSI on March 25, 2015.
LEAP5000XS upgrade: NUCAPT's LEAP is currently being upgraded with the newest CAMECA LEAP5000XS technology.
Photo credit: D. Isheim
We are very excited to very shortly have a CAMECA LEAP5000XS available to continue our atomic-scale imaging and analysis,featuring a single-atom position-sensitive time-of-flight detector with 80% detection efficiency, compared to 50% efficiency with the old LEAP4000XSi instrument we operated before
