scholarly journals Mechanical properties and microstructure of Al2O3/TiAl in situ composites doped with Cr and V2O5

2012 ◽  
Vol 44 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Kun Zhang ◽  
Wang Fen ◽  
Jianfeng Zhu ◽  
Huae Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
Strengthening Mechanism ◽  
Al2o3 Content ◽  
In Situ Composites ◽  
Al2o3 Ceramic ◽  
In Situ Composite

Al2O3/TiAl in situ composites doped with Cr and V2O5 were successfully prepared from Ti, Al, TiO2, Cr and V2O5 by hot pressing. The effect of in situ formed Al2O3 content on the phase composition, microstructure and mechanical properties of Al2O3/TiAl composites were investigated. The results show that the as-synthesized composites mainly consisted of ?-TiAl/?2-Ti3Al matrix and dispersive Al2O3 reinforcing phases. The in situ formed fine Al2O3 ceramic particles mainly disperse on the grain boundaries of TiAl, resulting in refinement of TiAl matrix, which improves the mechanical properties of the Al2O3/TiAl in situ composite. The composite with 7.54 at.% Al2O3 possesses the maximum flexural strength and fracture toughness of 335.38 MPa and 5.39 MPa m1/2, respectively. The strengthening mechanism was also discussed in detail.

scholarly journals Fabrication and mechanical properties of Al2O3/TiAl in situ composites doped with Nb2O5

2015 ◽  
Vol 47 (3) ◽  
pp. 311-317 ◽  
Author(s):  
F. Wang ◽  
N. Fan ◽  
J. Zhu ◽  
H. Jiang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Press ◽  
Dispersion Method ◽  
Powder Mixtures ◽  
In Situ Composites ◽  
Microstructures And Mechanical Properties

Al2O3/TiAl composites were successfully fabricated from powder mixtures of Ti, Al, TiO2, Cr2O3 and Nb2O5 by a hot-press-assisted exothermic dispersion method. The effect of the Cr2O3 and Nb2O5 addition on the microstructures and mechanical properties of Al2O3/TiAl composites was characterized. The results showed that the specimens are mainly composed of TiAl, Ti3Al, Al2O3, NbAl3 and Cr2Al. The Vicker-hardness and density of Al2O3/TiAl composites increase gradually with the increase of Nb2O5 content. When the Nb2O5 content was 6.54 wt %, the flexural strength and fracture toughness of the composites have a maximum values of 789.79 MPa and 9.69 MPa?m1/2, respectively. The improvement of mechanical properties is discussed in detail.

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.

Microstructure and Mechanical Properties of SICP/MoSi2 Composites Manufactured by In Situ Reaction and Hot Pressing

2011 ◽  
Vol 341-342 ◽  
pp. 204-209
Author(s):  
Han Ying Wang ◽  
Gao Shan Ma ◽  
Yan Qing Yang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Glass Phase ◽  
Volume Fraction ◽  
Strengthening Mechanism ◽  
Dispersion Strengthening ◽  
Sic Particles

Pure MoSi2and MoSi2composites with different volume fraction of SiC particles were prepared by the technology of in situ reaction and hot pressing the pure powder of Mo, Si and C after alcohol mixing. The effects of in situ formed SiC particles on the microstructure, the flexural strength and fracture toughness of SiCP/MoSi2composites were studied. The research shows the relative density, flexural strength and fracture toughness of the composites are increased compared with those of the pure MoSi2material. It is found that the in–situ formed SiC particles refine the MoSi2grains and eliminate the brittle SiO2glass phase. The strengthening mechanism of the composites is of the refinement of MoSi2grains,dispersion strengthening of the in–situ formed SiC particles and elimination of the brittle SiO2glass phase.

Effect of TiC Content on the Microstructure and Mechanical Properties of Ti3AlC2/Al2O3 In Situ Composites Synthesized by Hot Pressing

2012 ◽  
Vol 724 ◽  
pp. 278-281 ◽  
Author(s):  
Lan Ye ◽  
Jian Feng Zhu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
High Temperatures ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Microstructure And Mechanical Properties ◽  
Reactive Hot Pressing

The Ti3AlC2/Al2O3 in situ composites were successfully synthesized from the system of Ti-TiC-Al-TiO2 by reactive hot pressing at 1350 °C. The effect of TiC content on the phase composition, microstructure and mechanical properties were investigated in detail. The results indicate that the fabricated products possess the highest purity as the TiC contents reduce to 90 % of its theoretical content. This deviation is mainly attributed to the decomposition of Ti3AlC2 and vaporization of Al at high temperatures. The effect of TiC content on the fracture toughness, flexural strength, Vickers hardness of Ti3AlC2/Al2O3 composites was also discussed in detail.

Mechanical properties of NiAl-Mo composites produced by specially controlled directional solidification

2012 ◽  
Vol 1516 ◽  
pp. 255-260 ◽  
Author(s):  
G. Zhang ◽  
L. Hu ◽  
W. Hu ◽  
G. Gottstein ◽  
S. Bogner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Directional Solidification ◽  
Creep Resistance ◽  
Room Temperature ◽  
Growth Direction ◽  
Nominal Composition ◽  
Potential Candidate ◽  
In Situ Composites

ABSTRACTMo fiber reinforced NiAl in-situ composites with a nominal composition Ni-43.8Al-9.5Mo (at.%) were produced by specially controlled directional solidification (DS) using a laboratory-scale Bridgman furnace equipped with a liquid metal cooling (LMC) device. In these composites, single crystalline Mo fibers were precipitated out through eutectic reaction and aligned parallel to the growth direction of the ingot. Mechanical properties, i.e. the creep resistance at high temperatures (HT, between 900 °C and 1200 °C) and the fracture toughness at room temperature (RT) of in-situ NiAl-Mo composites, were characterized by tensile creep (along the growth direction) and flexure (four-point bending, vertical to the growth direction) tests, respectively. In the current study, a steady creep rate of 10-6s-1 at 1100 °C under an initial applied tensile stress of 150MPa was measured. The flexure tests sustained a fracture toughness of 14.5 MPa·m1/2at room temperature. Compared to binary NiAl and other NiAl alloys, these properties showed a remarkably improvement in creep resistance at HT and fracture toughness at RT that makes this composite a potential candidate material for structural application at the temperatures above 1000 °C. The mechanisms responsible for the improvement of the mechanical properties in NiAl-Mo in-situ composites were discussed based on the investigation results.

Damage of T300 Carbon Fiber during Precursor Pyrolysis

2008 ◽  
Vol 368-372 ◽  
pp. 1019-1021
Author(s):  
Song Wang ◽  
Zhao Hui Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Phenolic Resin ◽  
Poor Performance ◽  
Precursor Polymers

C/SiC, C/Si-O-C and C/C composites reinforced with T300 carbon fiber were fabricated via polycarbosilane (PCS), polysiloxane (PSO), and phenolic resin precursor polymers infiltration/pyrolysis, respectively. Flexural strength and fracture toughness of the composites were evaluated. The results showed that all the composites had poor mechanical properties, less than 160 MPa in flexural strength and 5 MPa•m1/2 in fracture toughness. Deep investigation illuminated that the fiber was damaged severely during the preparation of the composites, especially in the first cycle of precursor pyrolysis. Great degradation of the fiber has relationship with coarsening of the microstructure. Bad in-situ strength of the fiber resulted in poor performance of the composites.

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.

The Effects of MgO Content on the Mechanical Properties and Microstructures of Al2O3-TiN-TiC Ceramic Materials

2012 ◽  
Vol 500 ◽  
pp. 623-628 ◽  
Author(s):  
Yu Huan Fei ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
Crack Path ◽  
Ceramic Materials ◽  
Optical Microscope ◽  
Volume Percent ◽  
Sintered Ceramic ◽  
Microstructure Morphology

Al2O3-TiN-TiC ceramic materials with different MgO content were fabricated by hot-pressing technique. The MgO volume percent was varied from 0vol% to 5vol%. The mechanical properties such as flexural strength, Vickers hardness and fracture toughness were tested. The phase composition of the sintered body was analyzed by XRD while the microstures of the sintering body were observed by OM (Optical Microscope) and SEM. The effects of MgO content on the mechanical properties and microstructures of Al2O3-TiN-TiC were investigated. The results shows that the addition of MgO can change the phase composition of the sintered ceramic materials which displayed with diverse solid solutions and intermetallic compounds. Meanwhile the new sintering products changed the the microstructure morphology which made the crack path complex and affected the mechanical properties.

Microstructure and Mechanical Properties of Hot-Pressed and Pressureless Sintered WC-Al2O3 Ceramic Composites

1993 ◽  
Vol 327 ◽  
Author(s):  
Hidehiro Endo ◽  
Masanori Ueki
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Composite System ◽  
Ceramic Composites ◽  
Pressureless Sintering ◽  
Sintering Aid ◽  
Al2o3 Ceramic ◽  
Remarkable Improvement

AbstractFully densified WC-A12O3 composites were successfully consolidated by both hot-pressing and pressureless sintering. The optimum hot-pressing condition for the composites was 1700°C for 2h under a pressure of 40MPa. A remarkable improvement in mechanical properties was achieved in the composite system, especially in WC-30 and -70vol%A12O3, compared to the monolithic WC and A12O3 ceramics. The addition of MgO as a sintering aid had a great effect on the properties of the composites. WC-30vol%A12O3 composite with 1.Owt% MgO addition exhibited flexural strength higher than 1000MPa up to 1200°C, fracture toughness; KIC≥7MPa√m, and hardness; HV ≥2450. In pressureless sintering with the addition of MgO as a sintering aid and subsequent HIP treatment, the WC-30vol%A12O3 composite exhibited the flexural strength higher than 900MPa up to 1200°C.

A Study on Mechanical Properties and Strengthening Mechanisms of AA5052/ZrB2 In Situ Composites

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Narendra Kumar ◽  
Gaurav Gautam ◽  
Rakesh Kumar Gautam ◽  
Anita Mohan ◽  
Sunil Mohan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Strengthening Mechanisms ◽  
In Situ Composites ◽  
Solid Solution Strengthening ◽  
Theoretical Yield ◽  
The Matrix

In the present study, in situ reaction technique has been employed to prepare AA5052 matrix composites reinforced with different vol. % of ZrB2 particles (i.e., 0, 4.5, and 9 vol. %). Composites have been characterized by X-ray diffraction (XRD) to confirm the in situ formation of ZrB2 particles in the matrix. Optical Microscopy (OM) studies reveal the refinement of aluminum-rich phase due to the presence of ZrB2 particles. Scanning electron microscopy (SEM) studies reveal size and distribution of ZrB2 particles while transmission electron microscopy (TEM) reveals the presence of dislocations in the matrix around ZrB2 particles. Hardness and tensile testing of composites have been carried out at room temperature to evaluate the mechanical properties. The results reveal the improvement in hardness and strength with increased amount of ZrB2 particles. Strength of AA5052/ZrB2 in situ composites has been analyzed by various strengthening mechanism models. The analysis revealed that Orowan and Solid solution strengthening mechanisms are the predominant mechanism for high strength composites. Theoretical yield strength is about 6–10% higher than the experimental values due to clustering tendency of ZrB2 particles.

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