Micropyretic synthesis of NiAl containing Ti and B

2000 ◽  
Vol 15 (1) ◽  
pp. 63-75 ◽  
Author(s):  
G. K. Dey ◽  
A. Arya ◽  
J. A. Sekhar
Keyword(s):  
Combustion Front ◽  
Microstructural Characterization ◽  
Quaternary Alloy ◽  
Combustion Reaction ◽  
Alloying Elements ◽  
Two Phase ◽  
Alloying Additions ◽  
Boride Phases ◽  
Effect Of Alloying

The effect of alloying additions of Ti and B on the process of micropyretic synthesis on NiAl and on the microstructure of the synthesized alloy was examined. It was observed that the combustibility of the quaternary alloy is good despite the presence of the alloying elements because of an additional combustion reaction between Ti and B. The microstructure of the quaternary alloy was found to consist primarily of the NiAl and Ti boride phases. The effect of preheating of the specimen prior to synthesis on the process of synthesis was also examined. It was observed that preheating not only can change the morphology of the phases but also influence the nature of the phases present in the alloy. The mechanism of the formation of the two phase microstructure during the synthesis from the elemental powders was established by stopping the combustion front and by carrying out a detailed microstructural characterization of regions around the stopped combustion front.

Microstructural Characterization of α2 + γ Titanium Aluminides

1997 ◽  
Vol 3 (S2) ◽  
pp. 701-702
Author(s):  
D. J. Larson ◽  
M. K. Miller
Keyword(s):  
Titanium Aluminides ◽  
Base Alloy ◽  
Significant Proportion ◽  
Weight Ratio ◽  
High Strength ◽  
Microstructural Characterization ◽  
Two Phase ◽  
Tial Alloys ◽  
Boron Doped

Two-phase α2+γ TiAl alloys with microalloying additions, Fig. 1, are of interest due to the high strength-to-weight ratio they can provide in automotive and aircraft applications. In boron-doped α2+γTiAl containing Cr, Nb, and W, the B levels were found to be significantly depleted below the nominal alloy content in both the α2 andγ phases. The boron solubilities in the γ and α2 phases were 0.011 ± 0.005 at. % B and 0.003 ± 0.005 at. % B, respectively in Ti-47% Al-2% Cr-1.8% Nb-0.2% W-0.15 % B that was aged for 2 h at 900°C (base alloy). The majority of the B was in a variety of borides including TiB, TiB2 and a Cr-enriched (Ti,Cr)2B precipitate. With the exception of the smaller (< 50 nm thick) Cr-enriched (Ti,Cr)2B precipitates, Fig. 2, most of the borides were larger than ∼100 nm. A significant proportion of the microalloying additions is in these borides, Table 1.

scholarly journals Microstructural characterization of Cu82.3Al8.3Mn9.4 shape memory alloy after rolling

10.30544/314 ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 281-289
Author(s):  
Mirko Gojić ◽  
Stjepan Kožuh ◽  
Ivana Ivanić ◽  
Magdalena Selanec ◽  
Tamara Holjevac Grgurić ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Microstructural Characterization ◽  
Rolling Process ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Hot And Cold Rolling

In this paper, the microstructure of Cu82.3Al8.3Mn9.4 (in wt. %) shape memory alloy after hot and cold rolling was investigated. The Cu82.3Al8.3Mn9.4 alloy was produced by a vertical continuous casting method in the form a cylinder rod of 8 mm in diameter. After the casting, hot and cold rolling was performed. By hot rolling a strip with a thickness of 1.75 mm was obtained, while by cold rolling a strip with a thickness of 1.02 mm was produced. After the rolling process, heat treatment was performed. Heat treatment was carried out by solution annealing at 900 °C held for 30 minutes and water quenched immediately after heating. The microstructure characterization of the investigated alloy was carried out by optical microscopy (OM), scanning electron microscopy (SEM) equipped with a device for energy dispersive spectroscopy (EDS). Phase transformation temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC) method. The homogenous martensite microstructure was confirmed by OM and SEM micrographs after casting. During rolling the two-phase microstructure occurred. Results of DSC analysis showed martensite start (Ms), martensite finish (Mf), austenite start (As) and austenite finish (Af) temperatures.

Microstructural Characterization of a High Copper (Nd0.75Pr0.25)2Fe14B Magnet

2014 ◽  
Vol 802 ◽  
pp. 518-523 ◽  
Author(s):  
Marcos F. de Campos ◽  
Daniel Rodrigues ◽  
Flavia P. Vitoretti ◽  
Leonardo V. Tavares ◽  
Kaio S.T. de Souza ◽  
...  
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Microstructural Characterization ◽  
Alloying Elements ◽  
Edax Analysis ◽  
High Copper ◽  
Microstructural Data ◽  
Scanning Electron

A commercial magnet following the N 48 specification was submitted to a detailed microstructural characterization. The magnet presents 10 kOe of coercivity and good 2ndquadrant squareness. The grain size is around 10 micrometers. Scanning electron microscope (SEM) EDAX analysis shows that it is a high copper NdPrFeB alloy following the 3Nd:1Pr proportion, with some aluminum. The magnet was covered by a 15 micrometers layer, with nickel and copper. The microstructural data allow a better understanding of the effect of the alloying elements.

Effect of Alloying Elements on Graphite Morphology in CGI

2010 ◽  
Vol 649 ◽  
pp. 171-176 ◽  
Author(s):  
Martin Selin ◽  
Daniel Holmgren ◽  
Ingvar L. Svensson
Keyword(s):  
Thermal Conductivity ◽  
Material Properties ◽  
Alloying Elements ◽  
Alloying Element ◽  
Cast Irons ◽  
Compacted Graphite ◽  
Alloying Additions ◽  
Graphite Morphology ◽  
Shape And Size ◽  
Effect Of Alloying

Understanding how alloying elements and amounts affect the shape and size of graphite in compacted graphite cast irons could be of great importance. Some important material properties that are affected by the graphite shape are tensile strength and thermal conductivity. Knowing the effect of alloying additions could be of assistance when trying to optimise material for a specific application. In order to determine how graphite changes depending on alloying additions the microstructure of nineteen CGI materials were investigated. All melts were based on one chemical composition and alloying elements were added to obtain melts with variation in magnesium, silicon, copper, tin, chromium and molybdenum. Some of the more important microstructure features that were analysed are the amount and size of different graphite particles. The result from this analysis should give an indication on what features each alloying element affect and how these features varies with alloying amount.

scholarly journals Microstructural Characterization Of Quenched And Plastically Deformed Two-Phase α+β Titanium Alloys

2015 ◽  
Vol 60 (3) ◽  
pp. 2033-2038 ◽  
Author(s):  
M. Motyka ◽  
J. Sieniawski ◽  
W. Ziaja ◽  
G. Mrówka-Nowotnik
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Titanium Alloys ◽  
Thermomechanical Processing ◽  
Microstructural Characterization ◽  
Two Phase ◽  
Deformation Degree ◽  
Plastic Deformation Process ◽  
Deformation Processes

Abstract Development of microstructure in two-phase α+β titanium alloys is realized by thermomechanical processing – sequence of heat treatment and plastic working operations. Analysis of achieved results indicates that hot plastic deformation – depending on deformation degree – causes significant elongation of α phase grains. Following heat treatment and plastic deformation processes lead to their fragmentation and spheroidization. Characterization of microstructure morphology changes during thermomechanical processing of quenched Ti-6Al-4V and Ti-6Al-2Mo-2Cr alloys is presented in the paper. The effect of martensitic phase α’(α”) on microstructure development in plastic deformation process was confirmed.

scholarly journals Effect of alloying elements on thermal stability of Aluminium-Cerium based alloys

2020 ◽  
Author(s):  
Dheeraj Kumar Saini ◽  
Rahul Gope ◽  
Animesh Mandal
Keyword(s):  
Thermal Stability ◽  
Quaternary Alloy ◽  
Alloying Elements ◽  
Heat Treated ◽  
Different Temperatures ◽  
Thermal Stability Of ◽  
Effect Of Alloying

Abstract The effect of alloying elements on thermal stability of five different near eutectic Al-Ce based alloys, i.e., Al-12Ce, Al-12Ce-4Si, Al-12Ce-0.4Mg, Al-12Ce-4Si-0.4Mg and Al-12Ce-4Si-0.4Mg-0.25Sr alloys were investigated. The alloys were heat treated at three different temperatures, i.e., 200 °C, 300 °C and 400 °C to establish the thermal stability. Binary Al-12Ce alloy consisting of α-Al and showed higher resistance to coarsening at all temperatures. Addition of Si decreases the thermal stability above 200 °C while combined addition of Si and Mg increases the thermal stability up to 300 °C. Addition of Sr to quaternary alloy was not beneficial to enhance the thermal stability.

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

A Comparison of Tem and Apfim to the Interpretation of Modulated Microstructures

1985 ◽  
Vol 43 ◽  
pp. 70-71
Author(s):  
M.G. Burke ◽  
M.K. Miller
Keyword(s):  
Low Temperature ◽  
Microstructural Characterization ◽  
Superlattice Reflection ◽  
High Volume ◽  
Atom Probe ◽  
Dark Field ◽  
Miscibility Gap ◽  
Second Phase ◽  
Two Phase ◽  
Probe Field

Interpretation of fine-scale microstructures containing high volume fractions of second phase is complex. In particular, microstructures developed through decomposition within low temperature miscibility gaps may be extremely fine. This paper compares the morphological interpretations of such complex microstructures by the high-resolution techniques of TEM and atom probe field-ion microscopy (APFIM).The Fe-25 at% Be alloy selected for this study was aged within the low temperature miscibility gap to form a <100> aligned two-phase microstructure. This triaxially modulated microstructure is composed of an Fe-rich ferrite phase and a B2-ordered Be-enriched phase. The microstructural characterization through conventional bright-field TEM is inadequate because of the many contributions to image contrast. The ordering reaction which accompanies spinodal decomposition in this alloy permits simplification of the image by the use of the centered dark field technique to image just one phase. A CDF image formed with a B2 superlattice reflection is shown in fig. 1. In this CDF micrograph, the the B2-ordered Be-enriched phase appears as bright regions in the darkly-imaging ferrite. By examining the specimen in a [001] orientation, the <100> nature of the modulations is evident.

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