Nanoscale Precipitation in a Maraging Steel Studied by APFIM

2004 ◽  
Vol 10 (3) ◽  
pp. 342-348 ◽  
Author(s):  
Krystyna Stiller ◽  
Mats Hättestrand
Keyword(s):  
Maraging Steel ◽  
Material Properties ◽  
Three Dimensional ◽  
Atom Probe ◽  
Chemical Information ◽  
Phase Decomposition ◽  
Precipitation Sequence ◽  
Rich Phase ◽  
Complementary Methods ◽  
Prolonged Aging

This article summarizes findings from our previous investigations and recent studies concerning precipitation in a maraging steel of type 13Cr-9Ni-2Mo-2Cu (at.%) with small additions of Ti (1 at.%) and Al (0.7 at.%). The material was investigated after aging at 475°C up to 400 h using both conventional and three-dimensional atom-probe analyses. The process of phase decomposition in the steel proved to be complicated. It consisted of precipitation of several phases with different chemistry. A Cu-rich phase was first to precipitate and Mo was last in the precipitation sequence. The influence of the complex precipitation path on the material properties is discussed. The investigation clearly demonstrated the usefulness of the applied techniques for investigation of nanoscale precipitation. It is also shown that, complementary methods (such as TEM and EFTEM) giving structural and chemical information on a larger scale must be applied to explain the good properties of the steel after prolonged aging.

Nano-Scale Clusters Formed in the Early Stage of Phase Decomposition of Al-Mg-Si Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 357-360 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Tatsuo Sato
Keyword(s):  
Early Stage ◽  
Sheet Material ◽  
Three Dimensional ◽  
Natural Aging ◽  
Aging Treatment ◽  
Atom Probe ◽  
Phase Decomposition ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Nano Scale

The formation of nano-scale clusters (nanoclusters) prior to the precipitation of the strengthening b” phase significantly influences two-step aging behavior of Al-Mg-Si alloys. In this work, the existence of two kinds of nanoclusters has been verified in the early stage of phase decomposition by differential scanning calorimetry (DSC) and three-dimensional atom probe (3DAP). Pre-aging treatment at 373K before natural aging was also found to form preferentially one of the two nanoclusters, resulting in the remarkable restoration of age-hardenability at paint-bake temperatures. Such microstructural control by means of optimized heat-treatments; i.e. nanocluster assist processing (NCAP), possesses great potential for enabling Al-Mg-Si alloys to be used more widely as a body-sheet material of automobiles.

scholarly journals An atomic-scale view at the composition of amyloid-beta fibrils by atom probe tomography

2018 ◽  
Author(s):  
Kristiane A.K. Rusitzka ◽  
Leigh T. Stephenson ◽  
Agnieszka Szczepaniak ◽  
Lothar Gremer ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Atom Probe Tomography ◽  
Senile Plaques ◽  
Three Dimensional ◽  
Atom Probe ◽  
Pulse Frequency ◽  
Atomic Scale ◽  
Chemical Information ◽  
Protein Fibrils ◽  
Spectrometry Technique

ABSTRACTAmyloid-beta (Aβ) proteins play an important role in a number of neurodegenerative diseases. Aβ is found in senile plaques in brains of Alzeimer’s disease patients. The 42 residues of the monomer form dimers which stack to fibrils gaining several micrometers in length. Using Aβ fibrils with 13C and 15N marker substitution, we developed an innovative approach to obtain insights to structural and chemical information of the protein. We deposited the modified protein fibrils to pre-sharped aluminium needles with >100-nm apex diameters and, using the position-sensitive mass-to-charge spectrometry technique of atom probe tomography, we acquired the chemically-resolved three dimensional information for every detected ion evaporated in small fragments from the protein. We also discuss the influence of experimental parameters such as pulse energy and pulse frequency of the used Laser beam which lead to differences in the size of the gained fragments, developing the capability of localising metal atom within Aβ plaques.

An Investigation on Precipitation Behaviour of Cu-Rich Phase in Super304H Heat-Resistant Steel by Three Dimensional Atom Probe

2010 ◽  
Vol 654-656 ◽  
pp. 110-113
Author(s):  
Cheng Yu Chi ◽  
Jian Xin Dong ◽  
Wen Qing Liu ◽  
Xi Shan Xie
Keyword(s):  
Aging Time ◽  
Power Plants ◽  
Three Dimensional ◽  
Atom Probe ◽  
Strengthening Effect ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Rich Phase ◽  
Heat Resistant ◽  
Precipitation Behaviour

Super304H, a Cu-containing 18Cr-9Ni-3CuNbN heat-resisting steel is wildly used as an superheater/reheater tube material for ultra-super-critical (USC) power plants all over the world. It is recognized that the Cu-rich phase is an important strengthening phase for Super304H. However, the detail precipitation behaviour and its strengthening effect are still not very clear. Investigated material was taken from routine production and was aged at 650°C for different times. The precipitation of Cu-rich phase in Super304H was studied by three dimensional atom probe (3DAP) and TEM. Experimental results show that Cu-rich clusters have been formed at very early stage of 650°C aging. The Cu-rich particle images have been clearly caught just after 650°C aging for 5h. The Cu atoms gradually concentrate to Cu-rich particles and the other elements (such as Cr, Ni etc) diffuse away from Cu-rich particles to γ-matrix with the increasing of aging time. The Cu-rich particle size and its density have been determined as a function of aging time. Cu-rich particles still keep nano-size and distribute homogenously in grains even after long time (1,000h) aging, which is one of the most important reasons for keeping good strength of Super304H heat-resistant steel at high temperatures.

The role of Cu addition in the coercivity enhancement of sintered Nd-Fe-B permanent magnets

2009 ◽  
Vol 24 (2) ◽  
pp. 413-420 ◽  
Author(s):  
W.F. Li ◽  
T. Ohkubo ◽  
T. Akiya ◽  
H. Kato ◽  
K. Hono
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Permanent Magnets ◽  
Ion Beam ◽  
Three Dimensional ◽  
Atom Probe ◽  
Thin Layers ◽  
Scattered Electron ◽  
Rich Phase ◽  
Continuous Formation

To understand the mechanism of the coercivity enhancement by a trace addition of Cu in Nd-Fe-B sintered magnets, we investigated the microstructure difference between Cu-doped and Cu-free alloys using high resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), and laser assisted three dimensional atom probe (LA-3DAP). From a serial sectioning back scattered electron (BSE) images of the Nd-rich phase obtained by an integration of the focused ion beam (FIB) and HRSEM technique, it was found that Cu addition leads to a continuous formation of Nd-rich thin layers along the grain boundaries. 3DAP analysis has shown that a thin Cu-rich layer with a thickness of approximately 2 nm is present at the interface between the Nd2Fe14B and Nd-rich phase grains.

Prospects for Nanobiology with Atom-Probe Tomography

MRS Bulletin ◽  
2009 ◽  
Vol 34 (10) ◽  
pp. 744-750 ◽  
Author(s):  
Thomas F. Kelly ◽  
Osamu Nishikawa ◽  
J.A. Panitz ◽  
Ty J. Prosa
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Chemical Characterization ◽  
Atom Probe ◽  
Inorganic Materials ◽  
Mass Spectrometry Data ◽  
Chemical Information ◽  
Specimen Preparation ◽  
Flight Mass Spectrometry ◽  
Historical Developments

AbstractThe merits of atom-probe tomography (APT) of inorganic materials are well established, as described in this volume. However, one of the long-held aspirations of atom-probe scientists, structural and chemical characterization of organic and biological materials at near-atomic resolution, has yet to be fully realized. A few proof-of-concept type investigations have shown that APT of organic materials is feasible, but a number of challenges still exist with regard to specimen preparation and conversion of raw time-of-flight mass spectrometry data into a three-dimensional map of ions containing structural and chemical information at an acceptable resolution. Recent research aided by hardware improvements and specimen preparation advances has made some progress toward this goal. This article reviews the historical developments in this field, presents some recent results, and considers what life science researchers might expect from this technology.

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

scholarly journals Study on improving three-dimensional dynamic simulation model and equation of flexible fabric

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985284
Author(s):  
Meiliang Wang ◽  
Mingjun Wang ◽  
Xiaobo Li
Keyword(s):  
Simulation Model ◽  
Dynamic Simulation ◽  
Material Properties ◽  
Three Dimensional ◽  
Equation Solving ◽  
Study Results ◽  
Essential Properties ◽  
Dynamic Simulation Model ◽  
Novel Model ◽  
Simulation Equation

The use of the traditional fabric simulation model evidently shows that it cannot accurately reflect the material properties of the real fabric. This is against the background that the simulation result is artificial or an imitation, which leads to a low simulation equation. In order to solve such problems from occurring, there is need for a novel model that is designed to enhance the essential properties required for a flexible fabric, the simulation effect of the fabric, and the efficiency of simulation equation solving. Therefore, the improvement study results will offer a meaningful and practical understanding within the field of garment automation design, three-dimensional animation, virtual fitting to mention but a few.

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