scholarly journals Microstructural Characterization of TiC–White Cast-Iron Composites Fabricated by In Situ Technique

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 209 ◽  
Author(s):  
Aida B. Moreira ◽  
Ricardo O. Sousa ◽  
Pedro Lacerda ◽  
Laura M. M. Ribeiro ◽  
Ana M. P. Pinto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cast Iron ◽  
White Cast Iron ◽  
Microstructural Characterization ◽  
Industrial Applications ◽  
Homogeneous Distribution ◽  
Matrix Composites ◽  
High Temperature Synthesis ◽  
In Situ Technique

High-chromium white cast-iron specimens locally reinforced with TiC–metal matrix composites were successfully produced via an in situ technique based on combustion synthesis. Powder mixtures of Ti, Al, and graphite were prepared and compressed to fabricate green powder compacts that were inserted into the mold cavity before the casting. The heat of the molten iron causes the ignition of the combustion reaction of the reactant powders, resulting in the formation of the TiC by self-propagating high-temperature synthesis. The microstructure of the resultant composites and the bonding interfaces was characterized by scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The microstructural results showed a good adhesion of the composite, suggesting an effective infiltration of the metal into the inserted compact, yet a non-homogeneous distribution of the TiC in the martensite matrix was observed. Based on the results, the in situ synthesis appears to be a great potential technique for industrial applications.

Synthesis of Al-Al3Ti In Situ Metal Matrix Composites by Salt Route and Evaluation of their Mechanical Properties

2014 ◽  
Vol 984-985 ◽  
pp. 280-284 ◽  
Author(s):  
S.A. Kori ◽  
S.L. Biradar ◽  
Virupaxi Auradi
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Microstructural Characterization ◽  
Homogeneous Distribution ◽  
Matrix Composites ◽  
Commercial Purity Aluminum ◽  
Microstructural Studies

Current work, aims at preparation and characterization of Al-Al3Ti in-situ metal matrix composites with varying percentage of in-situ Al3Ti (3 and 5%) reinforcement. The composites were prepared by the salt route involving reaction of commercial purity aluminum (99.7%) and potassium titanium flourate halide (K2TiF6) salt at a reaction temperature of 800°C and with 60min. holding time. The prepared composites were subjected to microstructural studies using Scanning Electron Microscope. Further, the work aims at evaluating mechanical properties of the prepared composites as per ASTM standards. Microstructural characterization using SEM revealed blocky morphology of Al3Ti intermetallics with fairly homogeneous distribution. Insitu Al-Al3Ti composites have shown better mechanical properties when compared to the unreinforced Al matrix.

scholarly journals Preparation and Microstructural Characterization of a High-Cr White Cast Iron Reinforced with WC Particles

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2596
Author(s):  
Aida B. Moreira ◽  
Laura M. M. Ribeiro ◽  
Pedro Lacerda ◽  
Ricardo O. Sousa ◽  
Ana M. P. Pinto ◽  
...  
Keyword(s):  
Cast Iron ◽  
Base Metal ◽  
White Cast Iron ◽  
Microstructural Characterization ◽  
Ex Situ ◽  
Matrix Composites ◽  
The Matrix ◽  
Eutectic Constituent ◽  
Cold Pressed

High-chromium white cast iron (WCI) specimens locally reinforced with WC–metal matrix composites were produced via an ex situ technique: powder mixtures of WC and Fe cold-pressed in a pre-form were inserted in the mold cavity before pouring the base metal. The microstructure of the resulting reinforcement is a matrix of martensite (α’) and austenite (γ) with WC particles evenly distributed and (Fe,W,Cr)6C carbides that are formed from the reaction between the molten metal and the inserted pre-form. The (Fe,W,Cr)6C precipitation leads to the hypoeutectic solidification of the matrix and the final microstructure consists of martensite, formed from primary austenite during cooling and eutectic constituent with (Fe,Cr)7C3 and (Fe,W,Cr)6C carbides. The presence of a reaction zone with 200 µm of thickness, between the base metal and the composite should guarantee a strong bonding between these two zones.

Microstructural Characterization of In Situ TiB Whiskers in Ti MMCs Fabricated by SPS

2007 ◽  
Vol 336-338 ◽  
pp. 1310-1312
Author(s):  
Hai Bo Feng ◽  
De Chang Jia ◽  
Yu Zhou ◽  
Qing Chang Meng
Keyword(s):  
Electron Microscopy ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Microstructural Characterization ◽  
Average Diameter ◽  
Matrix Composites ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

The in situ TiB whisker reinforced titanium matrix composites were prepared by mechanical alloying followed by spark plasma sintering. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to characterize the microstructure of the TiB whiskers. The effect of sintering temperature on morphologies of in situ TiB whiskers was evaluated. With the increase of spark plasma sintering temperature, the average diameter of in situ TiB whiskers increased. The in situ TiB whiskers exhibited a hexagonal shape with (100), (101) and (10 1 ) planes at the transverse section and a growth orientation of [010]TiB direction.

Synthesis and Forming of Titanium Matrix Composites by Casting Route

2007 ◽  
Vol 334-335 ◽  
pp. 297-300
Author(s):  
Si Young Sung ◽  
Bong Jae Choi ◽  
Young Jig Kim
Keyword(s):  
Electron Microscopy ◽  
Melting Furnace ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron

The aim of this study is to evaluated the possibility of the in-situ synthesized (TiC+TiB) reinforced titanium matrix composites (TMCs) for the application of structural materials. In-situ synthesis and casting of TMCs were carried out in a vacuum induction melting furnace with Ti and B4C. The synthesized TMCs were characterized using scanning electron microscopy, an electron probe micro-analyzer and transmission electron microscopy, and evaluated through thermodynamic calculations. The spherical TiC plus needle-like and large, many-angled facet TiB reinforced TMCs can be synthesized with Ti and B4C by a melting route.

The influence of titanium addition on wettability of high-chromium white cast iron-matrix composites

2018 ◽  
Vol 53 (11) ◽  
pp. 1567-1576 ◽  
Author(s):  
Takalani Madzivhandila ◽  
Shepherd Bhero ◽  
Farouk Varachia
Keyword(s):  
Cast Iron ◽  
White Cast Iron ◽  
Mining Industry ◽  
Titanium Content ◽  
High Wear Resistance ◽  
Matrix Composites ◽  
Ferrous Alloys ◽  
Titanium Addition ◽  
High Chromium ◽  
Wetting Properties

The mining industry exerts ever increasing demand for components with high wear resistance to the extent that plain ferrous alloys are falling short. Innovative metal-matrix composites non-ferrous metals have been widely researched and used. Casting composites based on ferrous alloys pose monumental challenges in casting. First, the density differential results in large buoyant forces on the ceramic such that unless a rigid structure is configured, the less dense ceramic floats on the metal stream. Second, the poor wetting properties between metal and ceramic will result in inferior bonding of the matrix, hence separation of solids in service. The paper attempts to improve the bonding characteristics of zirconia and alumina through wettability studies. High-chromium white cast iron was used as a substrate. The wetting behavior of molten iron on the substrates of zirconia and alumina was investigated. The study shows that alumina is poorly wetted with copper and nickel; the wetting angles were higher than 90°. Thus, the envisaged coating of alumina with copper or nickel prior to casting of ferrous melts will not significantly alter or improve wettability of alumina. Between copper and nickel, nickel has better bonding with alumina than copper. Titanium in high-chromium white cast iron was found to improve the wetting characteristics on alumina. The wetting angle decreased with increased titanium content.

Solution-Based Synthesis of Magnesium Oxide Nanorods

1999 ◽  
Vol 581 ◽  
Author(s):  
Q. Wei ◽  
C.M. Lieber
Keyword(s):  
Electron Microscopy ◽  
Magnesium Oxide ◽  
Magnesium Chloride ◽  
Low Cost ◽  
Industrial Applications ◽  
Transformation Process ◽  
Matrix Composites ◽  
X Ray ◽  
Transmission Electron ◽  
Oxide Nanorods

ABSTRACTA solution-based synthesis route was developed to produce large quantities of MgO nanorods. Hydrated basic magnesium chloride, which has needle-like crystal structure, was used as a precursor. A subsequent two-step transformation process with magnesium hydroxide as an intermediate product was used to preserve the morphology of the precursor to yield magnesium oxide nanorods. Scanning electron microscopy, powder X-ray diffraction and energy dispersive X-ray spectroscopy show that the products are very pure (>95%) crystalline MgO nanorods with diameters from 40 nm to 200 nm and lengths 10 microns or longer. High-resolution transmission electron microscopy and electron diffraction further reveal that these MgO nanorods are single crystals and that the rod axis is along the <110> crystal direction. A model for the structural transformation from hydrated basic magnesium chloride to magnesium oxide has been developed and compared to our experimental results. This solution-based process can be easily scaled-up, and is a low-cost source of pure magnesium oxide nanorods needed in many industrial applications, for example, as reinforcing agents in matrix composites and as flux-pinning centers in high-TC superconductors.

In Situ Production of (Fe,Cr)7C3 Particulate Bundles Reinforced Iron Matrix Composites

2012 ◽  
Vol 602-604 ◽  
pp. 456-459
Author(s):  
Jing Lai Tian ◽  
Fang Xia Ye ◽  
Li Sheng Zhong ◽  
Yun Hua Xu
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
White Cast Iron ◽  
Treatment Time ◽  
Reference Sample ◽  
Chemical Compositions ◽  
Matrix Composites ◽  
Iron Matrix ◽  
Pin On Disc

In-situ production of (Fe,Cr)7C3 particulate bundles -reinforced iron matrix composite was prepared by infiltration casting between Cr wires and white cast iron at 1200°C plus subsequent heat treatment. The composites under different heat treatment times were comparatively characterized by scanning electron microscopy (SEM) and pin-on-disc wear resistance tests. The results show that the area of the particle bundles gradually increases with the heat treatment time increasing, and the chemical compositions change from eutectic to hypoeutectic, the morphologies of the reinforcements present chrysanthemum-shaped, granular and intercrystalline eutectics. Under 5 N loads, the composites appear excellent wear resistance, which is 36 times for the reference sample.

Infiltration Casting and In Situ Fabrication of (Fe,Cr)7C3 Particulates Bundle – Reinforced Iron Matrix Composites

2011 ◽  
Vol 284-286 ◽  
pp. 273-276
Author(s):  
Li Sheng Zhong ◽  
Yun Hua Xu ◽  
Xin Cheng Liu ◽  
Fang Xia Ye ◽  
Jing Lai Tian ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
Phase Analysis ◽  
Matrix Composite ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Matrix Composites ◽  
Iron Matrix

The method of infiltration casting plus heat treatment process employing chromium wires and cast iron applied to in-situ synthesized (Fe,Cr)7C3 particulates bundle reinforced iron matrix composites. The phase analysis, microstructure, microhardness and wear-resistance of composite were observed and measured. The results show that it is possible to fabricate (Fe,Cr)7C3 particulates bundle reinforced iron matrix composite produced by this technology, and a special structure which called particulates bundle was fabricated. (Fe,Cr)7C3 particulates bundle were distributed in the forms of granular, lath-shaped and hexagon-shaped in the particulates bundle. The macrohardness of particulates bundle was 52 HRC, and the relative wear resistance of the composites is 2.3—23 times higher than that of the cast iron.

Microstructural Characterization of Consolidant Products for Historical Renders: An Innovative Nanostructured Lime Dispersion and a More Traditional Ethyl Silicate Limewater Solution

2012 ◽  
Vol 18 (5) ◽  
pp. 1181-1189 ◽  
Author(s):  
Giovanni Borsoi ◽  
Martha Tavares ◽  
Rosário Veiga ◽  
Antonio Santos Silva
Keyword(s):  
Electron Microscopy ◽  
Microstructural Characterization ◽  
Silica Gels ◽  
Ethyl Silicate ◽  
Homogeneous Distribution ◽  
X Ray ◽  
Agglomeration Process ◽  
Surface Consolidation ◽  
Scanning Electron

AbstractThe conservation and durability of historical renders must be carried out through compatible techniques and materials. An important operation is the restitution of historical renders cohesion, turned friable by the loss of binder, usually due to physical and/or chemical actions. Surface consolidation is based on the use of materials with aggregating properties. This operation is reached usually through the application of organic or mineral consolidants, but inorganic consolidants are becoming preferred due to better compatibility and durability. In this article two mineral compatible consolidation products were studied: a commercial suspension of calcium hydroxide nanoparticles in propanol and a limewater dispersion of ethyl silicate. Microscopy (optical and scanning electron microscopy) and X-ray microanalyses of the consolidation products and of the consolidated mortar specimens were carried out. To assess the mechanical properties and product's efficacy, analyses of the compression, flexural strength, and superficial hardness were performed. Microscopy results show that limewater dispersion of ethyl silicate forms platelike silica gels, which can interfere in product penetration. Otherwise, nanolime particles permit homogeneous distribution and optimum penetration on the treated substrate, improving cementing action and the agglomeration process.

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