bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reducing Size Effect of Grahite in Malleable iron by Prestressing before Heat Treatment
Authors: Plenard Elisabeth , Fromont Claude 
Published: March 2011

ABSTRACTThe present article aims to show that high intensity compressive prestressing applied to white iron to be malleabilized, alters the final structure of the iron after malleabilization. The graphite nodules are finer and more numerous and ferritisation is greater. The phenomenon increases, with several factors as follows: intensity, repetitionmultiaxiality of prestress and hot prestressing.Initial results of the study of correlations between finer graphite structure and certain mechanical properties show that there is little change to static properties, but some dynamic properties are improved (1).
First Stage Graphitization of Subcritically Treated White Cast Iron
Authors: Hussein A. A. , El-Menawati L. I. , Kassem M. A. , Yostos B. I. 
Published: March 2011

ABSTRACTThe kinetics of first stage graphitization was studied in white cast irons of different compositions. These irons were presubjected to various isothermal anneals at 300–500°C, after being step-quenched from the intercritical (austenite and carbide) region. As a consequence of such pretreatment, the kinetics of post first stage graphitization were substantially accelerated. Both light and scanning electron metallography hive indicated that such acceleration arises due to the creation of vast areas of austenite/carbide interfaces upon cooling to and during subcritical transformations. These interfaces act as favourable nucleation sites for graphite and additionally they provide shorter diffusion paths for carbon. The latter also allows faster growth of graphite nodules. Effects of varying Si and Hn contents of the cast iron were determined. The practical significance of such treatment in providing] faster malleabilization and uniform distribution of graphite nodules is thus evident.
Effects of Nickel substitution by Manganese in Austenitic S.G. Cast Iron for Low-Temperature Uses
Authors: Poyet P. , Couchinave P. , Dancoisne P. I. 
Published: March 2011

ABSTRACTFor an economical purpose, an austenitic spheroidal graphite cast iron grade, containinq nickel-manganese, has been developed to replace Ni-Resist cast iron, type D2M, for cryogenic applications.Several tests were carried out to produce semi-industrial. heats of 200 kg so as to cast samples with a thickness ranging between 25 and 75 mm, and a variable nickel and manganese content. The resulting grades were compared each other and with Ni-Resist cast irons, before and after heat treatment, for their metallographic structure, their hardness, their mechanical tensile properties at room temperature and their impact values at temperatures down to - 150° C.The results show that it is possible to produce cast iron grades with 7 to 10 % manganese and 9 to 11 % nickel contents, featuring, at quenched state, better mechanical tensile properties at room temperature than Ni- Resist D2M with a 22–25 % Ni content, for roughly equivalent impact values at low temperatures. For as-cast material, the properties obtained vary with material thickness, and ductility is steeply decreasing for thicknesses under 30 mm.Weldability of Ni/Mn cast iron can be compared to Ni-Resist D2M weldability; machinability however seems more difficult, especially when boring quenched material.Generally speaking, the overall properties of these new grades and their lower cost-price if compared to Ni-Resist cast iron, should lead to promising outlets for low temperature uses and/or applications requiring high-level mechanical properties.
The Spherulitic Growth of Graphite
Authors: Minkoff I. 
Published: March 2011

ABSTRACTThe spherulitic growth of graphite from the melt is described in terms of instability mechanisms. Initially a pyramidal form grows which becomes unstable on the bounding face and a stellar polyhedral form results. The number of polyhedral facets increases in growth and the polyhedral apex angle decreases with the decrease of undercooling due to recalescence. Finally a rounded spherical form is produced.The observations are taken from different experimental programmes, and from observations reported in the literature. Some comparison is also made with the behaviour of silicon under similar growth conditions.
A Study of Austempered Ductile Cast Iron
Authors: Verhoeven J. D. , Nagar A. El , Sarnagawa B. El , Cornwell D. P. , Laabs F. 
Published: March 2011

ABSTRACTExperiments were carried out on unalloyed ductile cast iron to evaluate the % retained austenite (%RY) and its lattice parameter as a function of austenitizing time and temperature for austempering temperatures ranging from 270 to 420°C. Results are related to expected carbon levels in the gamma iron matrix at the austenitizing temperature. It is shown that the rate of austenitization can be described as a two step process and experiments demonstrate that 900°C austenitizatlon is complete after 8m. An 1100°C homogenizatdon has been shown to have a small effect upon %RY and rate of austenitization.
Graphite Morphology Control in Cast Iron
Authors: Subramanian S. V. , Kay D. A. R. , Purdy G. R. 
Published: March 2011

ABSTRACTGraphite morphology in cast iron is analyzed in terms of the growth kinetics of graphite crystals in liquid iron. At small driving forces, i.e., low supersaturation or small kinetic undercooling, graphite growth is characterized by faceted growth, resulting in flake, compacted and spherulitic graphite morphologies. However, at large driving forces, there is a transition from facted to non-faceted growth, resulting in a dendritic growth morphology.Flake morphology is rationalized in terms of impurity dependent crystal growth mechanisms, whereas a spherulitic morphology is attributed to a defect controlled spiral growth mechanism. Compacted graphite morphology is considered as a transition between flake and spherulitic morphology.A thermodynamic approach is used to inter-relate the residual concentrations of impurities of technological interest, i.e. S and 0, as a function of the residual concentration of the reactive elements, Mg, Ca, and Ce in a typical cast iron melt at 1500'C and atmospheric pressure. Such a diagram that quantitatively relates graphite morphology in thick cast iron sections to soluble concentrations of impurities is referred to as a graphite morphology control diagram.In thin section castings that freeze at faster cooling rates and large kinetic undercoolings, the basal spiral growth mechanism dominates over the impurity controlled prism growth mechanism, leading to deviations from predictions based simply on the graphite morphology control diagram. In the ase of compacted graphite, where growth on both the prism and basal faces is involved, the degree of nodularity increases with the cooling rate, giving rise to section sensitivity.At large undercoolings, the prevention of the nucleation and growth of cementite is an essential feature of graphite morphology control. It is estimated that the mobility of the cementite interface exceeds that of the prism interface in flake graphite growth by an order of magnitude and that of the basal interface in spherulitic graphite growth by three orders of magnitude. In practice, the driving force for graphite growth is raised selectively through the addition of graphite stabilizing elements, such as silicon, which raise the temperature of the graphite eutectic and depress the temperature of the carbide eutectic. Kinetic growth undercooling can be decreased by increasing the number of heterogeneous nuclei for graphite growth through inoculation. The application of the above concepts for the control of graphite morphology in shaped automotive castings is discussed.
673K Embrittlement of Ferritic Spheroidal Graphite Cast Iron
Authors: Yanagisawa O. , Lui T. S. 
Published: March 2011

ABSTRACTIntergranular fracture had been observed in the temperature range from 573K – 673K, where the ductilit miniTum appears at 673K for the strain rate of sec−1 in ferritic spheroidal graphite cast irons.The cause of intergranular fracture at about 673K has been investigated. The following two points are emphasized. The first is the role of hydrostatic tensile stress in triaxial stress field developed in ferrite matrix among graphite nodules, relating to the effect of graphite volume fraction on the intergranular fracture. The second is the role of carbide precipitation during dynamic strain ageing, relating to the strain rate and the temperature dependence of the intergranular fracture.
Graphite Inoculants For Gray Cast Iron
Authors: Loper C. R. , Shirvani S. , Witter T. H. 
Published: March 2011

ABSTRACTThe ability of graphitic materials to serve as inoculants during the solidification of flake graphite cast irons has been examined and related to the physical structure of these materials. Carbon dissolution in cast iron melts is reviewed relative to dissolution rates and carbon recovery obtained from a variety of materials. Maximum dissolution rates and carbon recovery are shown to be attained with high purity carbon products, where the ash present does not form a network structure as carbon enters solution, and where the sulfur content of the carbon product is low.Successful inoculation requires that the carbon product be graphitic, or possess a high degree of graphiticity, and that the solution rate be controlled so that the substrate graphite is present in the molten iron at the time of graphite formation during solidification. The characteristics of inoculants whereby this controlled solution rate can be achieved are discussed.Inoculation with graphitic materials is shown to be effective in flake graphite cast irons, but is not effective in spheroidal or compacted/vermicular graphite cast irons. Factors contributing to this effect are discussed.
Time-Resolved Studies of Rapid Solidification in Highly
Undercooled Molten Silicon
Authors: Lowndes D.H. , Jellison G.E. , Wood R.F. , Pennycook S.J. , Carpenter R.W. 
Published: March 2011

ABSTRACTA KrF (248 nm) pulsed laser was used to melt 90-, 190-, and 440-nm thick
amorphous silicon layers produced by Si ion implantation into (100)
crystalline Si substrates. Time-resolved reflectivity measurements at two
different probe wavelengths (633 nm and 1.15 μm) and post-irradiation TEM
measurements were used to study the formation of an undercooled liquid Si
phase and the subsequent solidification processes. The time-resolved
measurements provide new experimental information about the nucleation of
fine-grained Si crystallites in undercooled liquid Si, at low laser energy
densities (Eℓ), and about the growth of large-grained Si in the
near-surface region at higher Eℓ. Measurements with the infrared
probe beam reveal the presence of a buried, propagating liquid layer at low
??. Model calculations indicate that this liquid layer is generated in part
by the release of latent heat associated with the nucleation and growth
process.
Relation Between Temperature and Solidification Velocity in
Rapidly Cooled Liquid Silicon
Authors: Thompson M. O. , Bucksbaum P. H. , Bokor J. 
Published: March 2011

ABSTRACTA semi-empirical method to determine the undercooling-velocity relationship
for laser induced melting is presented. The technique uses measurements of
melt depth versus time to control numerical simulations, resulting in a map
of the interface temperature as a function of time, and consequently as a
function of the interface velocity. The results are independent of any model
for the velocity-undercooling relationship. Results of the technique on
simulated and experimental melt depth data are presented. Transient
conductance data on 28 nanosecond 694 nm laser irradiation of silicon
indicate an undercooling-velocity slope of 17±3 K/(m/sec) near the melting
point. Picosecond optical transmission data show a much smaller slope.
Laser-Induced Surface Ripples: What is Understood and What is
Not
Authors: Fauchet P.M. , Siegman A.E. 
Published: March 2011

ABSTRACTThe most predominant ripple properties can be explained by existing
perturbative theories. We present experimental results on novel types of
ripples, which suggest that theory has to go beyond first-order perturbation
and that the material's response is not well understood.
Laser Irradiation of Ge(100): An Assessment of Surface Order
with He Diffraction
Authors: Lambert W. R. , Trevor P. L. , Schulberg M. T. , Cardillo M. J. , Tully J. C. 
Published: March 2011

ABSTRACTWe investigate the effects of Nd:YAG and excimer laser irradiation on the
Ge(100) surface under UHV conditions over a temperature range 140 < T(K)
< 300 using the surface sensitive probe of He atom diffraction. We study
the effects of irradiation on surface damage and order using the apparent
(2×1) ࢐ c(2×4) transition. We monitor surface contamination in situ. The
temporal thermal response is modeled theoretically to aid in assessing the
experimental results. The capability to maintain a Ge(100) surface at low
temperatures free of contamination and well ordered is demonstrated.
Electric Conductivity of Vitreous Silica during Pulsed-Electron-Beam Irradiation
Authors: Stern Stanley H. , Fiorito Ralph B. 
Published: March 2011

ABSTRACTWe describe a measurement of the transient conductivity induced in amorphous SiO2during irradiation by an intense and energetic electron beam. Preliminary results of an experiment [1] we performed at the Pulsed High - Energy Radiographic Machine Emitting X Rays (PHERMEX) facility of Los Alamos National Laboratory indicate that a beam of electrons of energy 17.5 MeV, of current density 1 kA/cm2, and of micropulse duration 3 nsec induce in a-SiO2an electric conductivity 007E 6 × 10-3(03A9-cm)-1. This value is 15 orders of magnitude larger than the ordinary (ionic) conductivity of the material [2].
Kinetics and Mechanisms of Solid Phase Epitaxy and Competitive
Processes in Silicon
Authors: Olson G.L. 
Published: March 2011

ABSTRACTRecent progress in studies of temperature dependent kinetic competition
during solid phase crystallization of silicon is reviewed. Specific areas
which are emphasized include: the enhancement of solid phase epitaxial
growth rates by impurity-induced changes in electronic properties at the
crystal/amorphous interface, the influence of impurity diffusion and
precipitation in amorphous silicon on the kinetics of epitaxial growth, the
effects of impurities on the kinetic competition between solid phase epitaxy
and random crystallization, and the kinetics of solid phase crystallization
at very high temperatures in silicon.
Explosive Crystallization in A-Ge Films Irradiated with
Microsecond Laser Pulses
Authors: Sharma R.K. , Bansal S.K. 
Published: March 2011

ABSTRACTExplosive crystallisation has been observed in deposited a-Ge films
irradiated with pulsed Nd-glass laser beam of 400 micro second duration.
Transmission electron microscopic examination of the irradiated film shows a
polycrystalline region surrounded by radial dendrites of ~ 8-10 ;Cm size.
Analysis of the results is consistent with the duplex-melting model of the
explosive crystallisation mechanism. Heat released during the amorphous to
crystalline transformation of a localised region abruptly crystallises the
surrounding area resulting in dendritic growth. The crystallisation is
self-sustaining untill the temperature ahead of liquid/amorphous interface
drops below 775 K. These results are consistent with earlier study of
explosive crystallisation in unsupported a-Ge films and further confirm that
the heat loss to the underlying substrate governs the dynamics of the
crystallisation process.
Dynamic Annealing Phenomena and the Origin of RTA-Induced
“Hairpin” Dislocations
Authors: Maszara W. , Sadana D.K. , Rozgonyi G.A. , Sands T. , Washburn J. , Wortman J.J. 
Published: March 2011

ABSTRACTThe geometry, origin, and diffusion along hairpin defects in Si were
investigated using TEM and SIMS techniques. The defect that grows from the
amorphous-crystalline (a/c) interface following solid phase epitaxy growth
front was found to be a perfect dislocation with a/2(101) Burgers vector.
Misoriented microcrystallites within the a/c transition region are proposed
to be nucleation sites for the hairpin dislocations. The density of the
crystallites increases with an overall coarsening of the interface which
occurs during dynamic annealing processes stimulated by implantation or
post-implantation low temperature annealing. Hairpin dislocations were found
to pipe-diffuse boron at much higher rates than bulk processes significantly
shifting dopant profiles. The diffusion coefficient of boron pipe diffusion
at 1150°C was found to be about 104 times higher than the bulk
one.
A Comparison of Deep Levels Generated In InP by Proton and
Deuteron Bombardment
Authors: Macrander A. T. , Schwartz B. 
Published: March 2011

ABSTRACTA predominant deep level which has an activation energy of 0.4 eV was found
to have been formed in the region between the surface and the end-of-range
of 200 keV ions. In the fluence range 1012 −
1013cm−2 essentially no difference between the deep
level spectra for proton and deuteron bombardments was found.
Rapid Thermal Annealing in Si
Authors: Seidel T.E. , Pai C.S. , Lischner D.J. , Maher D.M. , Knoell R.V. , Williams J.S. , Penumalli B.R. , Jacobson D.C. 
Published: March 2011

ABSTRACTCertain aspects of Rapid Thermal Annealing (RTA) are reviewed. Temperature
considerations are discussed. The implant disorder removal rate is measured
(5eV removal energy for As induced damage). Shallower defect-free junctions
are obtained using RTA. Results of a ”Round Robin”-RTA annealing are
presented, transient enhanced diffusion is not prominent for As. New results
for the concentration enhanced diffusion of As are presented. Diffusion from
the channeling-tai1 region of shallow boron diffusions is noted as a
limiting factor for producing shallow p+-junctions. Other issues
are briefly discussed.
Rapid Thermal Annealing of Pre-Amorphized B and
BF2-Implanted Silicon
Authors: Calder I.D. , Naguib H.M. , Houghton D. , Shepherd F.R. 
Published: March 2011

ABSTRACTShallow p+n junctions have been formed through a combination of
pre-amorphization of the silicon surface by implantation of 28Si,
33Ar, or 73Ge, low energy implantation of boron or
BF2+, and rapid thermal annealing (RTA) in a tunqsten halogen lamp
system. Both pre-amorphization and RTA are required to form a shallow
(<0.25 μm) junction, for either boron or BF2+. Arqon pre-amorphization results in poor electrical activation
of the boron, while germanium gives the lowest sheet resistivity, but is
responsible for a deep boron tail during implantation. The residual damage
is characterized by a plane of dislocation loops centred either close to the
boron concentration peak, for B+ implantation into a crystalline
substrate, or at the original amorphous-crystalline interface, for
pre-amorphized specimens.
Light-Induced, Short-Time Annealing of Silicon-Implanted
Layers
Authors: Wouters D. , Maes H.E. 
Published: March 2011

ABSTRACTShort time anneal experiments were performed in a specially developed
annealing system based on a bank of Tungsten-Halogen lamps. The annealing
process during the temperature transient was studied as a function of the
illumination time with the system operating in the constant maximum power
regime. By using this procedure it was shown that electrical activation of
all elements (B, P, As) considered in this study is completed within the
transient period without noticeable diffusion. Redistribution of the
implanted profiles was only observed for longer times after the steady state
temperature was reached. Pre-amorphization with Argon is found to
significantly alter and retard the annealing behaviour.
Formation of Shallow P+ Junctions Using Two-Step
Anneals
Authors: Drowley C.I. , Adkisson J. , Peters D. , Chiang S.-Y. 
Published: March 2011

ABSTRACTShallow (0.15-0.2 μm deep) p+ junctions have been formed using boron
implanted into silicon which was pre-amorphized using a silicon implant. The
implants were annealed using a two-step process; initially the wafers were
furnace annealed at 600 °C for 100 min., followed by a rapid isothermal
anneal (RIA) at 950-1100 °C for 10 sec. For comparison, some wafers were
only given a single-step rapid isothermal anneal at 950-1100 °C for 10 sec.
The shallowest junctions were formed when the amorphous silicon layer was
deeper than the boron implant, because of the suppression of channelling.
When the amorphous/crystalline interface was shallower than the tail of the
boron implant, some channeling occurred. This channeling tail exhibited an
enhanced diffusion during the single-step RIA which was reduced
significantly by the two-step anneal. When the amorphous layer was deeper
than the boron implant, the single-step and two-step anneals gave identical
results.
Impurity Diffusion During RTA
Authors: Fair R.B. 
Published: March 2011

ABSTRACTEnhanced dopant diffusion during RTA depends upon whether the following
physical phenomena occur individually or in combination: (1) amorphization
of the Si, (2) damage-induced dislocation formation, (3) damage annealing,
(4) self-interstitial trapping, (5) solubility enhancement. RTA of B in
crystalline or preamorphized Si presents significantly different
environments for enhanced diffusion. In preamorphized Si, enhanced B
diffusion is modeled as increased B solubility following SPE. In addition, a
different intrinsic diffusivity is observed which corresponds to B diffusion
in preamorphized Si. Anomalous diffusion of B and As from high dose implants
can be modeled with the same mechanism -- self-interstitial trapping
following SPE.
Solid-Phase Epitaxial Regrowth of Ion-Implanted Silicon on
Sapphire Using Rapid Thermal Annealing
Authors: Hodge A M , Cullis A G , Chew N G 
Published: March 2011

ABSTRACTSolid phase epitaxial regrowth of silicon on sapphire is used to improve the
quality of as-received silicon films prior to conventional device
processing. It has been shown that this is necessary, especially for layers
of 0.3μm and thinner, if the full potential of this particular silicon on
insulator technology is to be realised. Si+ ions are implanted at
an energy and dose such that all but the surface of the silicon film is
rendered amorphous. In this study, the layer is regrown using a rapid
thermal annealer operated in the multi-second regime. A second shallower
implant followed by rapid thermal annealing produces a further improvement.
Characterisation of the material has been principally by cross-sectional
transmission electron microscopy. The structures observed after different
implant and regrowth treatments are discussed.
Epitaxy and Defects in Laser-Irradiated, Single-Crystal
Bismuth
Authors: Helms Aubrey L. , Draper Clifton W. , Jacobson Dale C. , Poate John M. , Bernasek Steven L. 
Published: March 2011

ABSTRACTThe (0001), (1010), and (2110) faces of Bi have been pulse laser melted at
0.5 J/cm2 with a Q-switched Ruby laser. Nomarski Interference
Contrast Microscopy, Channeling, and selective chemical etching have been
used to investigate the response to the laser irradiation. The response of
the material and the level of damage is shown to be strongly correlated to
the critical resolved shear stress characteristics in the particular
crystallographic direction studied.
Optical Furnace Annealing
Authors: Barrett Neil J. , Bartle D.C. , Todd A.G. , Grange J.D. 
Published: March 2011

ABSTRACTThe rapid annealing of Be implanted GaAs has produced electrical activations
of 70% for doses of 5 × 1014 cm−2 and hole profiles
similar to the as implanted distribution. Si implanted GaAs has also been
investigated using doses of 1 and 2 × 1014 cm−2 with
sheet resistivities of 40 Ω/square after rapid thermal annealing. GaAs has
been annealed with W-Si on the surface for the application of self aligned
gate FET technology. Temperature cycles upto 850°C are required to activate
the implanted dopant. Such cycles do not cause inter diffusion between the
W-Si and GaAs or deterioration of the metallisation surface morphology.