scholarly journals Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering

2018 ◽  
Vol 16 (1) ◽  
pp. 869-875
Author(s):  
Mediha İpek ◽  
Tuba Yener ◽  
Gözde Ç. Efe ◽  
Ibrahim Altınsoy ◽  
Cuma Bindal ◽  
...  
Keyword(s):  
High Hardness ◽  
Processing Technique ◽  
Metallic Phase ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
One Step ◽  
Intermetallic Matrix Composites ◽  
Hardness Values ◽  
A Current

AbstractIntermetallics are known as a group of materials that draws attention with their features such as ordered structure, high temperature resistance, high hardness and low density. In this paper, it is aimed to obtain intermetallic matrix composites and also to maintain some ductile Nb and Ti metallic phase by using 99.5% purity, 35-44 μm particle size titanium, niobium and aluminium powders in one step via recently developed powder metallurgy processing technique - Electric current activated/assisted sintering system (ECAS). In this way, metallic reinforced intermetallic matrix composites were produced. Dominant phases of TiAl3 and NbAl3 which were the first compounds formed between peritectic reaction of solid titanium, niobium and molten aluminum in Ti-Al-Nb system during 10, 30 and 90 s for 2000 A current and 1.5-2.0 voltage were detected by XRD and SEM-EDS analysis. Hardness values of the test samples were measured by Vickers indentation technique and it was detected that the hardnesses of intermetallic phases as 411 HVN whereas ductile metallic phase as 120 HVN.

Microstruciture and Properties of Intermetallic Matrix Composites Produced by Reaction Synthesis

1994 ◽  
Vol 350 ◽  
Author(s):  
D. E. Alman ◽  
J. A. Hawk ◽  
C. P. Dogan ◽  
M. Ziomek-Moroz ◽  
A. V. Petty
Keyword(s):  
Alkaline Solutions ◽  
Reaction Synthesis ◽  
Matrix Composites ◽  
Reaction Products ◽  
Hot Press ◽  
Press Temperature ◽  
Intermetallic Matrix ◽  
Microstructural Evaluation ◽  
Intermetallic Matrix Composites

AbstractIn this US Bureau of Mines study, a variety of TiAl based composites were produced in situ by reaction synthesis. Mixtures of elemental Ti, Al and B and Ti, Al, and Si powders were reactive hot-pressed to form TiAl reinforced with 10, 20, 25 or 60 vol. pct. TiB2 or Ti5Si3. Microstructural evaluation of the resultant composites confirmed that the reaction products were primarily TiAl and TiB2 or Ti5S3, with a small amount of Ti3Al. The hot-press temperature and pressure had a significant effect on the density of the composites. In general, higher temperatures and initiating the reaction under pressure promoted dense composites. Room temperature biaxial flexure strength tests indicated that the addition of the reinforcing phases can improve the strength of TiAl. Potentiodynamic experiments revealed that TiAl, TiAl+TiB2 and TiAl+Ti5Si3 composites display active-passive corrosion behavior in both acidic and alkaline solutions.

Microstructure of intermetallic-matrix composites produced in situ by self-propagating high-temperature synthesis

1994 ◽  
Vol 52 ◽  
pp. 708-709
Author(s):  
C. P. Doğan ◽  
D. E. Alman
Keyword(s):  
High Temperature ◽  
Exothermic Reaction ◽  
Ceramic Composites ◽  
Matrix Composites ◽  
Temperature Synthesis ◽  
Intermetallic Matrix ◽  
High Temperature Synthesis ◽  
Wide Range ◽  
Intermetallic Matrix Composites

Self-propagating, high-temperature synthesis (SHS) is one method of material production in which elemental constituents are ignited, initiating a self-sustaining, exothermic reaction that results in their transformation into intermetallic and ceramic compounds. In addition, several reactions can be initiated within a single body to form intermetallic-intermetallic, intermetallic-ceramic, or ceramic-ceramic composites in situ. The driving force for the reactions is the negative heats of mixing of the forming compounds, which results in the liberation of heat. The obvious advantages of SHS processing are that it presents an opportunity to produce near net-shape advanced materials and composites with a high level of purity in a relatively low-cost and energy efficient manner.At the U.S. Bureau of Mines, we are actively involved in the SHS processing of a wide range of singlephase intermetallic and intermetallic-matrix composites: TiAl, TiAl+TiB2, TiAl+TiC, TiAl+Ti5Si3, MoSi2+SiC. One key element of our study is a thorough understanding of the effect of processing variables, such as composition, temperature, pressure, time, powder morphology, etc., on the microstructure, and hence the properties, of these materials.

The Formation Process of the Microstructure of Al2O3-Al3Ti-Al In-Situ Composite

1997 ◽  
Vol 3 (S2) ◽  
pp. 727-728
Author(s):  
H.H. Luo ◽  
D.Z. Wang ◽  
H.X. Peng ◽  
Cheng Liu ◽  
C.K. Yao
Keyword(s):  
Squeeze Casting ◽  
Volume Fraction ◽  
Average Diameter ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Al Composite ◽  
Heat Treated ◽  
Intermetallic Matrix Composites ◽  
Processing Techniques

In the last decade, new in-situ processing techniques, such as DIMOX™, XD™, VLS and SHS, for fabricating metal and intermetallic matrix composites have emerged. It is expected that the in-situ formed composites may reveal not only excellent dispersion of fine reinforcing particles, but high thermodynamical stability and high temperature performance. The fully dense Al2O3-Al3Ti-57Vol%Al composite was in-situ processed by combing combustion synthesis with squeeze casting utilizing the reaction between TiO2 powder (with average diameter of 0.6μm and volume fraction of 14%) and pure Al (99.5%). First, the 14Vol%TiO2/Al bulk materials were fabricated via squeeze casting method, subsequently, the TiO2/Al materials were heat treated to form final in-situ composites. Using XRD, SEM, TEM and HRTEM techniques, the microstructure and its evolution were investigated.The X-ray diffraction pattern of the composite is shown in Fig.1 which indicates that the composite is composed of A12O3, Al3Ti and Al. According to the reaction formula between TiO2 and Al the volume fraction of Al in the composite is about 57%. Fig.2 is a typical scanning electron micrograph of the composite.

The Application of Reactive Hot Compaction and In-Situ Coating Techniques to Intermetallic Matrix Composites

1993 ◽  
Vol 322 ◽  
Author(s):  
H. Doty ◽  
M. Somerday ◽  
R. Abbaschian
Keyword(s):  
Refractory Metal ◽  
Elevated Temperatures ◽  
Matrix Composites ◽  
Reaction Sequence ◽  
Intermetallic Matrix ◽  
Hot Compaction ◽  
Intermetallic Matrix Composites ◽  
In Situ Coating

AbstractAn overview of the application of the reactive hot compaction (RHC) process to fabricate various intermetallics such as silicides and aluminides is presented. Specific examples with the in-situ formation of diffusion barrier coatings on refractory metal reinforcements during RHC are also given. The processing involves blending the elemental powders with pre-treated refractory metal filaments and reactively synthesizing the mixture at elevated temperatures. During this process, the treated surfaces of the filaments react with one of the components (e.g. Al for aluminides or Si for silicides) to form in-situ a protective surface coating. The important influence of the RHC reaction sequence and rate on the consolidation of the composite are discussed. Finally, the fracture toughness of the composites are related to the various toughening mechanisms, with special emphasis on the role of the interfacial layer.

Particulate Intermetallic Matrix Composite Made by One-Step Pulsed Laser Deposition

1992 ◽  
Vol 273 ◽  
Author(s):  
Li-Chyong Chen ◽  
Ernest L. Hall ◽  
Karen A. Lou
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Optical Films ◽  
The Matrix ◽  
One Step ◽  
Intermetallic Matrix Composites

ABSTRACTA novel way of producing particulate intermetallic matrix composites based on Nb-Al in one step using pulsed laser deposition (PLD) has been investigated. One unique characteristic, inherent to laser ablation, is the generation of particulates. These particulates condense on the substrate and become part of the film. In some cases, such as in high Tc superconducting or optical films applications, it is believed that the presence of particulates diminishes the quality of the films. In this work, we demonstrate that it can be advantageous in some applications to incorporate these particulates into the films.Nb-Al films were prepared by laser ablation from a Nb3Al target using a 248nm KrF excimer laser at various fluences and substrate temperatures. Transmission (TEM) and scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Auger electron spectroscopy (AES) were used to characterize the samples. The resultant films consist of a homogeneous matrix with uniformly distributed inclusions. The size of the particles generated by PLD is in the range of a few tens of nanometers to a few microns. EDX shows that the matrix has a composition of Nb7A13 and the particulates contain barely detectable Al. The mechanism of the depletion of Al in the particulates will be discussed. The merit of having a ductile Nb phase embedded in the intermetallic matrix is evident as the cracks generated during TEM sample thinning process propagate in the brittle matrix and finally are arrested at the ductile inclusions.

Wear Behavior of SHS Intermetallic Matrix Composites

1994 ◽  
Vol 350 ◽  
Author(s):  
J. A. Hawk ◽  
D. E. Alman
Keyword(s):  
Wear Resistance ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Matrix Composites ◽  
Temperature Synthesis ◽  
Intermetallic Matrix ◽  
High Temperature Synthesis ◽  
Abrasive Wear Behavior ◽  
Intermetallic Matrix Composites

AbstractA number of discontinuously reinforced, intermetallic matrix composites (i.e., TiAl/TiC, TiAl/TiB2, TiAl/Ti5Si3) were formed in situ through self-propagating, high-temperature synthesis (SHS) between elemental powders. This Bureau of Mines study characterizes the abrasive wear behavior of these composites. Wear behavior is discussed with respect to process history, and type and volume fraction of reinforcement. Generally, higher process temperatures lead to dense composites, resulting in better wear resistance. The wear behavior of the SHS intermetallic composites is compared to other intermetallics, produced by conventional techniques.

MECHANICAL PROPERTIES OF IN-SITUFeAl-TiB2 INTERMETALLIC MATRIX COMPOSITES

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1479-1484 ◽  
Author(s):  
JONGHOON KIM ◽  
BONGGYU PARK ◽  
YONGHO PARK ◽  
IKMIN PARK ◽  
HEESOO LEE
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Arc Melting ◽  
The Matrix ◽  
Matrix Reinforcement ◽  
Intermetallic Matrix Composites ◽  
Properties Of Composites

Intermetallic matrix composites reinforced with ceramic particles have received a great deal of attention. Iron aluminide is known to be a good material for the matrix in such composites. Two processes were used to fabricate FeAl - TiB 2 intermetallic matrix composites. One was liquid melt in-situ mixing, and the other was arc melting and suction casting processes. FeAl - TiB 2 IMCs obtained by two different methods were investigated to elucidate the influence of TiB 2 content. In both methods, the grain size in the FeAl alloy decreased with the presence of titanium diboride. The grain size of in-situ FeAl - TiB 2 IMCs became smaller than that of arc FeAl - TiB 2 IMCs. Significant increase in fracture stress and hardness was achieved in the composites. The in-situ process gives clean, contamination-free matrix/reinforcement interface which maintained good bonding causing high load bearing capability. This contributed to the increase in the mechanical properties of composites.

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