In situ Formation of Hydroxyapatite-Whisker Ceramics by Hydrothermal Hot-Pressing Method

TiC/Ti3AlC2 composites were successfully prepared by hot-pressing sintering method from the elemental powder mixtures of Ti, Al and TiC. A possible reaction mechanism was investigated by XRD. The density, Vickers hardness, flexural strength, and fracture toughness of the TiC/Ti3AlC2 composites were also measured. At 660 °C, Al melted and reacted with Ti to form TiAl3. At 900 °C, TiAl3 reacted with TiC and Ti to form Ti2AlC. At 1100 °C, Ti2AlC reacted with TiC to form Ti3AlC2. Increasing the sintering temperature, the content of Ti3AlC2 increased. The TiC/Ti3AlC2 composites had excellent performance after sintered at 1100 °C, the density, Vickers hardness, flexural strength and fracture toughness of the composite were 4.35 g/cm3, 4.72 GPa, 566 MPa and 6.18 MPa·m1/2, respectively.

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Ti2AlC/TiAl Matrix Intermetallic Compound Prepared by In Situ Hot Pressing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.515 ◽

2014 ◽

Vol 602-603 ◽

pp. 515-518

Author(s):

Tao Tao Ai ◽

Fen Wang ◽

Chen Hui Yang

Keyword(s):

Intermetallic Compound ◽

Hot Pressing ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Pressing Method ◽

Temperature Oxidation ◽

Tial Intermetallic Compound ◽

Increasing Temperature ◽

Sintered Product

As the new structural material, TiAl intermetallic compound has great potential application in aerospace engine, energy and automotive fields. But the bottleneck problems including poor room temperature ductility and high-temperature oxidation resistance limit its application. Ti2AlC possesses an unusual combination of the merits of both metals and ceramics, which is considered the best reinforcement for TiAl intermetallic compound. In the present work, Ti2AlC/TiAl matrix intermetallic compound was successfully fabricated by in situ hot pressing method from the mixture of Ti/Al/TiC. The phase transitions were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The microstructure of the product was studied by scanning electron microscopy (SEM). Ti reacted with Al liquids to form Ti-Al intermetallics below 900 °C firstly. With increasing temperature (above 900 °C), a part of TiAl intermetallics reacted with TiC to form Ti2AlC reinforcement. The as-sintered product presented dense and typical lamellar structure. The in-situ synthesized fine Ti2AlC contributed to improve the strength of TiAl matrix intermetallic compound.

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Fabrication of Nano-MgO Reinforced Fe-Cr-Ni Composites by Reactive Hot Pressing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.620-622.551 ◽

2009 ◽

Vol 620-622 ◽

pp. 551-554 ◽

Cited By ~ 2

Author(s):

Chang Chen ◽

Jian Feng Yang ◽

Ji Qiang Gao ◽

Cong Yang Chu

Keyword(s):

Hot Pressing ◽

Low Temperatures ◽

Bending Strength ◽

Exothermic Reaction ◽

X Ray ◽

Three Point Bending ◽

Fine Grained ◽

In Situ Formation ◽

Reactive Hot Pressing

The self-propagating combustion reaction 0.741Mg + 0.247Fe2O3 + 0.188Ni + 0.318Cr → 0.741MgO + Fe0.494Ni0.188Cr0.318 was applied to prepare a nano-MgO reinforced Fe-Cr-Ni composite, by reactive hot pressing (RHP) under a condition of 700°C/30MPa/2h. The densification was enabled by the low temperatures produced by the exothermic reaction. According to TG-DTA and X-ray diffractometry (XRD), the highly-exothermic thermite reaction began at about 600°C and the in-situ formation of composites comprised predominantly of (FCC) Cr0.19Fe0.7Ni0.11, (FCC) Fe-Cr, (BCC) MgO and a small quantity of (BCC) MgFe2O4. The Vickers hardness was 3.67GPa, the three-point bending strength was 112.5±10MPa, and the fracture toughness was 3.28 MPa•m1/2. The microstructure of the composite was observed via scanning electron microscopy. This indicated that the distributions of in-situ-formed (BCC) MgO phases (~800 nanometers) were homogeneous into in a matrix of a fine-grained metallic alloy phases that gather together to form agglomerates in the composite.

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Synthesis of Ternary Machinable Al2O3/Ti2AlC Composites by High Energy Milling and In Situ Hot-Pressing Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.658.169 ◽

2010 ◽

Vol 658 ◽

pp. 169-172 ◽

Cited By ~ 1

Author(s):

Fen Wang ◽

Bo Bo Liu ◽

Jian Feng Zhu ◽

Ya Ling Li

Keyword(s):

Hot Pressing ◽

Raw Materials ◽

High Energy ◽

Milling Process ◽

Vacuum Furnace ◽

Composite Powders ◽

Pressing Method ◽

Fine Grained ◽

High Energy Milling

Al2O3/Ti2AlC composites were synthesized by high energy milling and hot-pressing at 1200°C in a vacuum furnace with a pressure of 4.8×10-2 Pa, using Ti, Al and C powder as raw materials. The effect of sintering temperature on the reactions, phase composition and microstructure of the synthesized products were investigated. The results show that the TiC and TiAl intermetallics composite powders were synthesized during the milling process. After the hot pressing, Ti2AlC phase was formed by the reaction between TiC and TiAl. A small amount of Al2O3 was also produced because of the oxidation of Al in the hot press process, which formed Al2O3/Ti2AlC composite together with the Ti2AlC at 1200°C. The fine grained Al2O3 particles disperse within Ti2AlC uniformly, which play a important role to strengthen Ti2AlC matrix, resulting in the increase of flexural strength and fracture toughness from 250 to 275.4MPa, 9.8 to 10.5MPa•m1/2, respectively.

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Microstructure and Mechanical Properties of Al2O3/TiAl In Situ Composites Doped with Fe2O3

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.597 ◽

2011 ◽

Vol 675-677 ◽

pp. 597-600

Author(s):

Liu Yi Xiang ◽

Fen Wang ◽

Jian Feng Zhu ◽

Xiao Feng Wang

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Flexural Strength ◽

Hot Pressing ◽

Rockwell Hardness ◽

Powder Mixtures ◽

Pressing Method ◽

Fe2o3 Content ◽

Maximum Value

Al2O3/TiAl in situ composites were successfully prepared by vacuum hot-pressing method with elemental powder mixtures of Ti, Al, TiO2 and Fe2O3. The effect of Fe2O3 addition on the microstructures and mechanical properties of Al2O3/TiAl composites has been investigated. The results show that the Rockwell hardness, flexural strength and fracture toughness of the composites increase with increasing Fe2O3 content. When the Fe2O3 content is 0.84 wt %, the flexural strength and the fracture toughness reach the maximum value of 624 MPa and 6.63 MPa·m1/2, respectively. The improvement of mechanical properties is firstly associated with a more homogeneous and finer microstructure developed by addition of Fe2O3; secondly, it is related to the increase of the ratio of α2-Ti3Al/γ- TiAl matrix phases.

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In situ formation of a cellular graphene framework in thermoplastic composites leading to superior thermal conductivity

Journal of Materials Chemistry A ◽

10.1039/c7ta00750g ◽

2017 ◽

Vol 5 (13) ◽

pp. 6164-6169 ◽

Cited By ~ 85

Author(s):

Fakhr E. Alam ◽

Wen Dai ◽

Minghui Yang ◽

Shiyu Du ◽

Xinming Li ◽

...

Keyword(s):

Thermal Conductivity ◽

Hot Pressing ◽

Single Step ◽

Thermoplastic Composites ◽

In Situ Formation

With single-step hot-pressing processes, a remarkable enhancement of the thermal conductivity of graphene/thermoplastic composites has been achieved, based on the formation of an interconnected, thermally percolating graphene framework in their matrix.

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