In Situ Formation of TiC Reinforced Intermetallic-Matrix Composite Layers Produced by Laser Cladding

2007 ◽  
Vol 336-338 ◽  
pp. 1380-1382 ◽  
Author(s):  
Ding Fan ◽  
Jian Bin Zhang ◽  
Yao Ning Sun ◽  
Jing Jie Dai ◽  
Rui Fu

Laser cladding technique was used to form Ni3(Si,Ti) intermetallic composite coating reinforced by in-situ formation TiC particles on Ni-based superalloy substrate. The experimental results showed that an excellent bonding between the coating and the substrate was ensured by a strong metallurgical interface. The clad coating was very well and free from cracks and pores. By means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), the effect of Ti-C addition to the microstructure and microhardness of the coating was investigated. The microstructure of the coating was mainly composed of Ni(Si), Ni3(Si,Ti) and TiC. The average microhardness of the coating was improved with increasing the Ti-C content. The microhardness was up to 780Hv when Ti-C addition was 20 wt. pct, which was much greater than that of Ni-based superalloy substrate.

Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.


2010 ◽  
Vol 663-665 ◽  
pp. 542-545 ◽  
Author(s):  
Bing Jie Zhu ◽  
Xin Wei Wang ◽  
Mei Fang Zhu ◽  
Qing Hong Zhang ◽  
Yao Gang Li ◽  
...  

The PANI/ITO conducting nanocomposites have been synthesized by in-situ polymerization. The obtained nanocomposites were characterized by X-ray diffraction pattern, scanning electron microscopy and Fourier transform infrared. Electrical conductivity measurements on the samples pressed into pellets showed that the maximum conductivity attained 2.0 ± 0.05 S/cm for PANI/ITO nanocomposites, at ITO doping concentration of 10 wt%. The results of the present work may provide a simple, rapid and efficient approach for preparing PANI/ITO nanocomposites.


Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 873
Author(s):  
Chun-Liang Yeh ◽  
Chih-Yao Ke

The fabrication of intermetallic/ceramic composites by combustion synthesis in the mode of self-propagating high-temperature synthesis (SHS) was investigated in the Al–Ni–Ti system with the addition of B4C. Two reaction systems were employed: one was used to produce the composites of xNiAl–2TiB2–TiC with x = 2–7, and the other was used to synthesize yNi3Al–2TiB2–TiC with y = 2–7. The reaction mechanism of the Al–Ni–Ti system was strongly influenced by the presence of B4C. The reaction of B4C with Ti was highly exothermic, so the reaction temperature and combustion velocity decreased due to increasing levels of Ni and Al in the reactant mixture. The activation energies of Ea = 110.6 and 172.1 kJ/mol were obtained for the fabrication of NiAl- and Ni3Al-based composites, respectively, by the SHS reaction. The XRD (X-ray diffraction) analysis showed an in situ formation of intermetallic (NiAl and Ni3Al) and ceramic phases (TiB2 and TiC) and confirmed no reactions taking place between Ti and Al or Ni. The microstructure of the product revealed large NiAl and Ni3Al grains and small TiB2 and TiC particles. With the addition of TiB2 and TiC, the hardness of NiAl and Ni3Al was considerably increased and the toughness was also improved.


2013 ◽  
Vol 457-458 ◽  
pp. 244-247
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The morphology of MMT/MgCl2/TiCl4 catalyst and PE/MMT nanocomposites was investigated by scanning electron microscopy (SEM). It can be seen that MMT/MgCl2/TiCl4 catalyst remained the original MMT sheet structures and many holes were found in MMT and the morphology of PE/MMT nanocomposites is part of the sheet in the form of existence, as most of the petal structure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were carried out to characterize all the samples. XRD results reveal that the original basal reflection peak of PEI1 and PEI2 disappears completely and that of PEI3 become very weak. MMT/MgCl2/TiCl4 catalyst was finely dispersed in the PE matrix. Instead of being individually dispersed, most layers were found in thin stacks comprising several swollen layers.


2020 ◽  
pp. 2050046
Author(s):  
TIANWEI YANG ◽  
ZHAOHUI WANG ◽  
SHIHAI TAN ◽  
FU GUO

To increase the strength and wear resistance of material surfaces, various combinations of B4C and 80TiFe powder were mixed into a Fe60 self-fluxing alloy powder; the composite coatings reinforced by TiB2–TiC were successfully prepared on Q235 steel surfaces by laser cladding. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to study the microstructure and chemical and phase composition. Microhardness and wear testers were used to investigate the mechanical properties. The results show that the interfaces of composite coatings and substrate materials are excellent for metallurgical bonding. The block-like TiB2 particles and flower-like TiC particles are uniformly distributed in the cladding coating. When the mass fraction of the mixed powder is 30%, the average microhardness of the coating is approximately 1100 HV[Formula: see text], which is 50% higher than that without the mixed powder, and demonstrates the best wear with a performance twice as better as that of the substrate.


2007 ◽  
Vol 336-338 ◽  
pp. 2200-2202 ◽  
Author(s):  
Wu Feng Jiang ◽  
Yun Han Ling ◽  
Su Ju Hao ◽  
Hong Yi Li ◽  
Xin De Bai ◽  
...  

Anodic aluminum oxide (AAO) is commonly used as a starting template for fabrication of several kinds of functional nanoscale devices due to its homogeneous nanohole structure with high aspect ratio. In this paper, high density and uniform titanium dioxide nanotube array films were prepared via liquid phase deposition method by immersing the AAO templates in an aqueous ammonium hexafluorotitanate solution. The phase and microstructure of the nanotube array films were characterized by X-ray diffraction and field-emission scanning electron microscopy. It was found that the mean inner diameters of nanotube are 40-100 nm, mainly depended on different templates and post treatment condition; the phase of as-deposited TiO2 array film was amorphous, while it became anatase at above 400°C.


2011 ◽  
Vol 52-54 ◽  
pp. 842-845 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong

TiAl/Ti2AlC in situ composite was successfully fabricated by hot-press-assisted reaction process from the mixture of Ti, Al and carbon black. The phase formation and transformation were investigated in detail by X-ray diffraction (XRD) and the morphology characteristics were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that when the mixed powders were hot pressed at 1300 °C for 1 h, full dense and highly pure TiAl/Ti2AlC composite was synthesized. The TiAl was the matrix phase and the in situ synthesized Ti2AlC was reinforcing phase. The reaction process was also discussed.


2015 ◽  
Vol 1120-1121 ◽  
pp. 572-575
Author(s):  
Hong Wei Liu ◽  
Feng Wang ◽  
Qiang Zhang ◽  
Xi Wu Li ◽  
Zhi Hui Li ◽  
...  

An innovative spray deposition technique has been applied to produce in situ TiB2/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using optical microscopy, scanning electron microscopy, and X-ray diffraction. Both theoretical and experimental results have shown that the TiB2particulates are formed in the microstructure. It was found that the TiB2particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB2particles are about 2 μm in size. Moreover, the presence of the TiB2particles was led to increasing of α’ phase with less 2 μm size in the composites which have a tendency to decompose to α+η structure.


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