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

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.

2011 ◽  
Vol 194-196 ◽  
pp. 1736-1739
Author(s):  
Fen Wang ◽  
Liu Yi Xiang ◽  
Jian Feng Zhu ◽  
Dong Li ◽  
Xiao Feng Wang

Al2O3/TiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with elemental powder mixtures of Ti, Al, TiO2and Cr2O3. The effect of Cr2O3addition on the microstructures and mechanical properties of Al2O3/TiAl composites has been characterized. The results show that the Rockwell hardness, flexural strength and fracture toughness of the composites increase with increasing Cr2O3content. When the Cr2O3content is 3.5 wt %, the flexural strength and the fracture toughness reach the maximum value of 658.7 MPa and 7.2 MPa•m1/2, respectively. The improvement of mechanical properties is firstly associated with a more homogeneous and finer microstructure developed by addition of Cr2O3; secondly, it is related to the increase of the ratio of α2-Ti3Al/γ- TiAl matrix phases.


2015 ◽  
Vol 47 (3) ◽  
pp. 311-317 ◽  
Author(s):  
F. Wang ◽  
N. Fan ◽  
J. Zhu ◽  
H. Jiang

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.


2011 ◽  
Vol 217-218 ◽  
pp. 680-683
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong

TiAl/Ti2AlC composites were successfully fabricated by hot-press-assisted reactive synthesis method from elemental powder mixtures of Ti, Al and C. The effect of C addition on the microstructures and mechanical properties of TiAl/Ti2AlC composites was investigated in detail. The results show that the Rockwell hardness, flexural strength and fracture toughness of the composites are modified by incorporation of in situ formed Ti2AlC. When the C content was 0.44 wt %, the flexural strength and the fracture toughness reach the maximum values of 658.7 MPa and 10.03 MPa•m1/2, respectively. The reinforcing mechanism was also discussed.


2011 ◽  
Vol 695 ◽  
pp. 227-230
Author(s):  
Liu Yi Xiang ◽  
Fen Wang ◽  
Jian Feng Zhu ◽  
Xiao Feng Wang

Al2O3/TiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with powder mixtures of Ti, Al, TiO2and Cr2O3as raw materials. The effect of sintering temperature on the microstructures and mechanical properties of Al2O3/TiAl composites has been investigated. The results show that the Rockwell hardness and density of the composites increased with increasing sintering temperature. But the flexural strength and fracture toughness peaked at 825 MPa and 7.29 MPa·m1/2, respectively, when the sintering temperature reached to1300 °C.


2015 ◽  
Vol 816 ◽  
pp. 200-204 ◽  
Author(s):  
Miao Miao Ruan ◽  
Xiao Ming Feng ◽  
Tao Tao Ai ◽  
Ning Yu ◽  
Kui Hua

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.


2011 ◽  
Vol 230-232 ◽  
pp. 789-792
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Fang Ni Du

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.


2011 ◽  
Vol 675-677 ◽  
pp. 597-600
Author(s):  
Liu Yi Xiang ◽  
Fen Wang ◽  
Jian Feng Zhu ◽  
Xiao Feng Wang

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.


2011 ◽  
Vol 695 ◽  
pp. 137-140
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong

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 %.


2011 ◽  
Vol 239-242 ◽  
pp. 413-416 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Shao Dan Li

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.


2012 ◽  
Vol 724 ◽  
pp. 278-281 ◽  
Author(s):  
Lan Ye ◽  
Jian Feng Zhu

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.


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