Reaction Synthesis of TiAl-Al2O3 Composites from Ti-Al-Cr2O3

2011 ◽  
Vol 211-212 ◽  
pp. 209-212
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Fang Ni Du
Keyword(s):  
Solid State ◽  
Titanium Aluminide ◽  
Reaction Synthesis ◽  
Hot Press ◽  
Prepared Material ◽  
The Matrix ◽  
Press Method ◽  
Ti Powder

Titanium aluminide composite reinforced with in situ formed submicron Al2O3 has been prepared by a reactive hot press method using Cr2O3, Al and Ti powder as starting materials. The reaction synthesis processing is particularly investigated. Results show that the matrix of the as-prepared material is a mixture of TiAl and a small amount of Ti3Al and Cr containing phase. Fine Al2O3 particles that act as reinforcing phase are dispersed along the interface of the matrix. The formation of TiAl/Al2O3 composite involves many transitional stages. Firstly, TiAl3 and Ti3Al intermediates were produced, then reducing reaction of Cr2O3 by Al formed Al2O3, and finally, the competitive solid-state diffusing reactions among Ti3Al, TiAl and TiAl3 produced the matrix phases of the TiAl/Al2O3 composite.

Reaction Synthesis of TiAl-Al2O3 Composite

2007 ◽  
Vol 336-338 ◽  
pp. 1397-1399 ◽  
Author(s):  
Jian Feng Zhu ◽  
Ji Qiang Gao ◽  
Fen Wang
Keyword(s):  
Titanium Aluminide ◽  
Reaction Synthesis ◽  
Hot Press ◽  
Prepared Material ◽  
The Matrix ◽  
Press Method ◽  
Al2o3 Particles ◽  
Ti Powder ◽  
Source Materials

Titanium aluminide composite reinforced with submicron Al2O3 has been prepared by a reactive hot press method using TiO2, Al and Ti powder as source materials. The reaction synthesis processing is particularly investigated. Results show that the matrix of the as-prepared material is a mixture of TiAl and a small amount of Ti3Al. Fine Al2O3 particles that act as reinforcing phase are dispersed along the interface of the matrix. The reduction of TiO2 involves many transitional stages, including Ti-Al reaction, TiO2-Ti reducing reaction, reaction between TiO2 and Al, etc.

Reaction Synthesis of TiAl/Ti2AlC In Situ Composites

2011 ◽  
Vol 695 ◽  
pp. 137-140
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Flexural Strength ◽  
Bending Strength ◽  
Reaction Process ◽  
Reaction Synthesis ◽  
Hot Press ◽  
Powder Mixtures ◽  
In Situ Composites ◽  
The Matrix ◽  
A Minor

Full dense and highly pure TiAl/Ti2AlC in situ composites were successfully synthesized by reactive synthesis from the powder mixtures of Ti, Al and carbon black by hot-press-assisted reaction process. The reaction process, microstructure and bending strength of the TiAl/Ti2AlC in situ composites were investigated in detail. The results show that the as fabricated composites posses three phases, namely, TiAl, Ti3Al and Ti2AlC. The matrix phases are mainly equiaxed TiAl with a minor lamellar Ti3Al phase. Ti2AlC particles with size less than 1 μm are distributed uniformly in matrix grains as a reinforcing phase. When C content is 0.44 wt %, the flexural strength reaches 426.21 MPa, which is increased by 35 %.

Effect of Si Addition on the Microstructures and Mechanical Properties of TiAl Intermetallics

2011 ◽  
Vol 239-242 ◽  
pp. 413-416 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Shao Dan Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Press ◽  
The Matrix ◽  
Press Method ◽  
Microstructures And Mechanical Properties ◽  
Si Content ◽  
Si Addition

TiAl/Ti5Si3 in situ composites were successfully fabricated by reactive hot-press method from powder mixtures of Ti, Al and Si. The influence of the Si addition on the microstructures and mechanical properties of TiAl/Ti5Si3 composites was investigated in detail. The results show that an appropriate amount of addition of Si refined the matrix structure obviously due to the in situ formed Ti5Si3, and as a result, the flexural strength and fracture toughness of the composites are modified. When the Si content is 1.82 wt %, the flexural strength and the fracture toughness reach the maximum value of 685.67 MPa and 9.02 MPa·m1/2, respectively. The enhancing mechanism was also discussed.

In Situ Produced MMC Layer by Laser Melt Injection

2010 ◽  
Vol 649 ◽  
pp. 61-66
Author(s):  
Zoltán Kálazi ◽  
Viktória Janó ◽  
Gábor Buza
Keyword(s):  
Carbon Content ◽  
Composite Layer ◽  
Pure Titanium ◽  
Base Material ◽  
Titanium Content ◽  
Steel Sample ◽  
Low Carbon ◽  
The Matrix ◽  
Ti Powder

Tungsten (W) based alloy composite layer reinforced with TiC particles has been successfully prepared on unalloyed steel sample by LMI technology. In order to obtain in situ produced TiC reinforcement, pure titanium has been introduced to the melt pool. WC powder was added for increasing the carbon content of the layer in order to avoid the softening of the matrix (with low carbon content) during TiC formation. The present study aims to investigate the optimum amount of injected WC and Ti powder to improve wear resistance and hardness of the layer. Samples were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The maximum hardness of the layer has been reached ~900HV in case of 2-4wt% of titanium content. Ti has been collected all of the carbon from the matrix when titanium content was 9,6wt%, which resulted that the austenite and (Fe,W)6C phases have been disappeared. Only α-Fe and TiC phases were presented in the layer. The hardness of the layer reduced to the hardness of the base material.

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.

Fabrication of TiAl/Ti2AlC Composite by Reaction Hot Pressing

2011 ◽  
Vol 52-54 ◽  
pp. 842-845 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Electron Microscopy ◽  
Reaction Process ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Composite ◽  
The Matrix ◽  
Morphology Characteristics ◽  
Scanning Electron

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.

Microstructure and Mechanical Properties of Al2O3/NiAl In Situ Composites by Hot-Press-Aided Reaction Synthesis

2012 ◽  
Vol 581-582 ◽  
pp. 548-551 ◽  
Author(s):  
Guo Quan Qi ◽  
Feng Shou Shangguan ◽  
Li Neng Yang ◽  
Qiang Bai ◽  
Gang Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Elemental Powder ◽  
Reaction Synthesis ◽  
Hot Press ◽  
Dispersion Method ◽  
Powder Mixtures

Al2O3/NiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with elemental powder mixtures of Ni, Al, NiO. The content of Al2O3 on the microstructures and mechanical properties of Al2O3/NiAl composites has been characterized. The results show that the Vickers hardness, flexural strength and fracture toughness of the composites increase with increasing Al2O3 content. When the Al2O3 content is 15 wt %, the flexural strength and the fracture toughness peaked at 765 MPa and 9.67 MPa•m 1/2, respectively. The improvement of mechanical properties is associated with a more homogeneous and finer microstructure developed by addition of Al2O3.

Effect of Ti Particle Size on Reaction Synthesis of Ti Aluminide

2012 ◽  
Vol 710 ◽  
pp. 314-319 ◽  
Author(s):  
Rohit Kumar Gupta ◽  
Bhanu Pant ◽  
Vijaya Agarwala ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Titanium Aluminide ◽  
Reaction Synthesis ◽  
Particle Sizes ◽  
Minor Phase ◽  
Chemical Homogeneity ◽  
Major Phase ◽  
Ti Powder

Titanium aluminide intermetallic was made through reaction synthesis (RS) process using elemental powders. Pressure assisted synthesis was carried out at high temperature under vacuum. Ti powder with two different particle sizes (200μm and 30μm average) were used in RS. Synthesized blocks were homogenized and characterized for chemical homogeneity, density, phase formation and microstructure evolution. Products near to theoretical density have been obtained with uniform chemistry after homogenization. Al3Ti as a major phase along with TiAl as minor phase was confirmed after RS and TiAl along with Ti3Al was observed after homogenization. Homogenization cycle was found to be different for the alloys made through different Ti particle sizes. Significant role of Ti particle size has been observed in this pressure assisted RS process.

Influence of Cr2O3 Addition on the Properties of TiAl Composites

2011 ◽  
Vol 230-232 ◽  
pp. 789-792
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Fang Ni Du
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Synthesis Method ◽  
Strengthening Mechanism ◽  
Reaction Synthesis ◽  
The Matrix ◽  
Method Effects ◽  
Particulate Reinforced

Using Ti, Al and Cr2O3 as starting materials, Al2O3 particulate reinforced TiAl composites have been fabricated by in-situ reaction synthesis method. Effects of the Cr2O3 addition on the microstructures and mechanical properties of the TiAl/Al2O3 composites were investigated in detail. The results show that the composites have a matrix of TiAl, Ti3Al, and minor Cr containing phases, and a second reinforcement Al2O3. The addition of Cr2O3 effectively refined the structure of the matrix, and as a result, the mechanical properties of TiAl composites are improved. At Cr2O3 7.36 wt%, the flexural strength and fracture toughness reach the maximum values of 634.62 MPa and 9.79 MPa·m1/2, which are increased by 80% and 30%, respectively. The strengthening mechanism is also discussed.

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