Consolidation of ultrafine-grained Cu powder and nanostructured Cu–(2.5–10) vol%Al2O3 composite powders by powder compact forging

2010 ◽  
Vol 45 (17) ◽  
pp. 4594-4605 ◽  
Author(s):  
A. Mukhtar ◽  
D. L. Zhang ◽  
C. Kong ◽  
P. Munroe
Keyword(s):  
Powder Compact ◽  
Composite Powders ◽  
Al2o3 Composite ◽  
Ultrafine Grained

Mechanical Behaviour of Ultrafine Grained Cu and Cu-(2.5 and 5) Vol.%Al2O3 Composites Produced by Powder Compact Forging

2011 ◽  
Vol 275 ◽  
pp. 170-173
Author(s):  
Aamir Mukhtar ◽  
De Liang Zhang
Keyword(s):  
Composite Powder ◽  
Powder Compact ◽  
High Energy ◽  
High Yield ◽  
High Yield Strength ◽  
High Fracture ◽  
Composite Powders ◽  
Al2o3 Composite ◽  
Ultrafine Grained ◽  
Powder Compacts

Nanostructured Cu-(2.5 and 5)vol.%Al2O3 composite powders were produced from a mixture of Cu powder and Al2O3 nanopowder using high energy mechanical milling, and then compacted by hot pressing. The Cu and Cu-Al2O3 composite powder compacts were then forged into disks at temperatures in the range of 500-800°C to consolidate the Cu and Cu-Al2O3 composite powders. Tensile testing of the specimens cut from the forged disks showed that the Cu forged disk had a good ductility (plastic strain to fracture: ~15%) and high yield strength of 320 MPa, and the Cu-(2.5 and 5)vol.%Al2O3 composite forged disks had a high fracture strength in range of 530-600 MPa, but low ductility.

scholarly journals Pulse Plasma Sintering of NiAl-Al2O3 Composite Powder Produced by Mechanical Alloying with Contribution of Nanometric Al2O3 Powder

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 407
Author(s):  
Katarzyna Konopka ◽  
Justyna Zygmuntowicz ◽  
Marek Krasnowski ◽  
Konrad Cymerman ◽  
Marcin Wachowski ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Composite Powder ◽  
Pulse Plasma ◽  
Alumina Powder ◽  
Composite Powders ◽  
Plasma Sintering ◽  
Al2o3 Composite ◽  
Ultrafine Grained ◽  
Pulse Plasma Sintering ◽  
Nial Matrix

NiAl-Al2O3 composites, fabricated from the prepared composite powders by mechanical alloying and then consolidated by pulse plasma sintering, were presented. The use of nanometric alumina powder for reinforcement of a synthetized intermetallic matrix was the innovative concept of this work. Moreover, this is the first reported attempt to use the Pulse Plasma Sintering (PPS) method to consolidate composite powder with the contribution of nanometric alumina powder. The composite powders consisting of the intermetallic phase NiAl and Al2O3 were prepared by mechanical alloying from powder mixtures containing Ni-50at.%Al with the contribution of 10 wt.% or 20 wt.% nanometric aluminum oxide. A nanocrystalline NiAl matrix was formed, with uniformly distributed Al2O3 inclusions as reinforcement. The PPS method successfully consolidated NiAl-Al2O3 composite powders with limited grain growth in the NiAl matrix. The appropriate sintering temperature for composite powder was selected based on analysis of the grain growth and hardness of Al2O3 subjected to PPS consolidation at various temperatures. As a result of these tests, sintering of the NiAl-Al2O3 powders was carried out at temperatures of 1200 °C, 1300 °C, and 1400 °C. The microstructure and properties of the initial powders, composite powders, and consolidated bulk composite materials were characterized by SEM, EDS, XRD, density, and hardness measurements. The hardness of the ultrafine-grained NiAl-Al2O3 composites obtained via PPS depends on the Al2O3 content in the composite, as well as the sintering temperature applied. The highest values of the hardness of the composites were obtained after sintering at the lowest temperature (1200 °C), reaching 7.2 ± 0.29 GPa and 8.4 ± 0.07 GPa for 10 wt.% Al2O3 and 20 wt.% Al2O3, respectively, and exceeding the hardness values reported in the literature. From a technological point of view, the possibility to use sintering temperatures as low as 1200 °C is crucial for the production of fully dense, ultrafine-grained composites with high hardness.

Microstructure and Mechanical Behaviour of Ultrafine Grained Al-4wt%Cu-(2.5-10) Vol.% SiC Metal Matrix Composites Produced by Powder Compact Forging

2011 ◽  
Vol 275 ◽  
pp. 208-213
Author(s):  
A. Gazawi ◽  
De Liang Zhang ◽  
K.L. Pickering ◽  
Aamir Mukhtar
Keyword(s):  
Metal Matrix ◽  
Powder Compact ◽  
Volume Fraction ◽  
High Energy ◽  
Matrix Composites ◽  
Plastic Yielding ◽  
Composite Powders ◽  
Ultrafine Grained ◽  
Powder Compacts ◽  
Small Plastic Strain

Ultrafine grained Al-4wt%Cu-(2.5-10) vol.% SiC metal matrix composite powders were produced from a mixture of Al, Cu and SiC powders using high energy mechanical milling (HEMM). The composite powders produced were first hot pressed at 300°C with a pressure of 240 MPa to produce cylindrical powder compacts with a relative density in the range of 80-94% which decreased with increasing the SiC volume fraction. Powder compact forging was utilized to consolidate the powder compacts into nearly fully dense forged disks. With increasing the volume fraction of SiC from 2.5% to 10%, the average microhardness of the forged disks increased from 73HV to 162HV. The fracture strength of the forged disks increased from 225 to 412 MPa with increasing the volume fraction of SiC particles from 2.5 to 10%. The Al-4wt%Cu-2.5vol.%SiC forged disk did not show any macroscopic plastic yielding, while the Al-4wt%Cu-(7.5 and 10)vol.% SiC forged disk showed macroscopic plastic yielding with a small plastic strain to fracture (~1%).

Investigation of Microstructure and Property of Fe3Al/Al2O3 Composites

2010 ◽  
Vol 150-151 ◽  
pp. 1409-1412 ◽  
Author(s):  
Tao Jiang
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Alloying ◽  
Sintering Process ◽  
Composite Powders ◽  
Al2o3 Composite ◽  
Al2o3 Phase ◽  
The Mean ◽  
Xrd Patterns ◽  
Al2o3 Matrix

The Fe3Al/Al2O3 composites were fabricated by pressureless sintering process. The Fe3Al intermetallics compounds powders were fabricated by mechanical alloying and heat treatment, then the Fe3Al powders and Al2O3 powders were mixed and the Fe3Al/Al2O3 composite powders were prepared, so the Fe3Al/Al2O3 composites were fabricated by sintering process at 1700oC for 2h. The phase composition and microstructure of Fe3Al intermetallics compounds powders produced by mechanical alloying and heat treatment were investigated. The phase composition, microstructure and mechanical properties of the Fe3Al/Al2O3 composites sintered bulks were investigated. The XRD patterns results showed that there existed Fe3Al phase and Al2O3 phase in the sintered composites. The Fe3Al/Al2O3 composites sintered bulks exhibited the homogenous and compact microstructure, the Fe3Al particles were homogenously distributed in the Al2O3 matrix, the mean particles size of Fe3Al intermetallics was about 3-5μm. The Fe3Al/Al2O3 composites exhibited more homogenous and compact microstructure with the increase of Fe3Al content in the Al2O3 matrix. The density and relative density of the Fe3Al/Al2O3 composites increased gradually with the increase of Fe3Al content. The fracture strength and fracture toughness of the Fe3Al/Al2O3 composites increased gradually with the increase of Fe3Al content. The elastic modulus and hardness (HRA) of the Fe3Al/Al2O3 composites decreased gradually with the increase of Fe3Al content.

Properties of ZrO2Al2O3 composite powders prepared from ZrAl metallo-organic compounds

1988 ◽  
Vol 100 (1-3) ◽  
pp. 413-417 ◽  
Author(s):  
Hideyuki Yoshimatsu ◽  
Tatsumi Yabuki ◽  
Hitoshi Kawasaki
Keyword(s):  
Organic Compounds ◽  
Composite Powders ◽  
Al2o3 Composite

Understanding structural evolution of nanostructured Cu-Al2O3 composite powders during thermomechanical processing

Materialia ◽  
2018 ◽  
Vol 4 ◽  
pp. 268-275 ◽  
Author(s):  
Dengshan Zhou ◽  
Zakaria Quadir ◽  
Charlie Kong ◽  
Hucheng Pan ◽  
Zhuang Liu ◽  
...  
Keyword(s):  
Thermomechanical Processing ◽  
Structural Evolution ◽  
Composite Powders ◽  
Al2o3 Composite

A novel way for fabricating ultrafine grained Cu-4.5 vol% Al2O3 composite with high strength and electrical conductivity

2019 ◽  
Vol 155 ◽  
pp. 109775 ◽  
Author(s):  
Chenguang Li ◽  
Yuehuang Xie ◽  
Dengshan Zhou ◽  
Wei Zeng ◽  
Jun Wang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Strength ◽  
Al2o3 Composite ◽  
Ultrafine Grained

Constrained network model for predicting densification behavior of composite powders

1987 ◽  
Vol 2 (1) ◽  
pp. 59-65 ◽  
Author(s):  
F. F. Lange
Keyword(s):  
Network Model ◽  
Powder Compact ◽  
Volume Fraction ◽  
Random Network ◽  
Simple Relation ◽  
Unit Cell ◽  
Densification Behavior ◽  
Inert Particle ◽  
Composite Powders ◽  
Inert Particles

Inert particles that do not contribute to the densification of a composite powder compact are visualized as located on network sites; the network is defined by the distribution of the particles in the powder matrix. Because the distances between neighboring network sites are not identical, the strain produced by the sintering powder between all inert particle pairs cannot be the same as that for the powder compact without the inert particles. The constrained network model is based on the hypothesis that the densification of the composite will be constrained by the network and will mimic that of the network. The shrinkage of the network, and thus the densification of the composite, is estimated with a periodic network. A distance between the minimum and maximum site pairs within the unit cell defines the distance between site pairs in the random network where the powder between the particles densifies in the same manner as that for the powder without the inert particle. When the particles form a continuous touching network, composite shrinkage and densification is nil. The chosen lattice must also conform to this condition. A simple relation was developed relating the densification behavior of the composite to that of the matrix without the inert particles and the parameter associated with the chosen lattice. By choosing the lattice formed by the tetrakaidecahedron unit cell (volume fraction of particles for a touching network = 0.277), remarkable agreement was achieved for the experimental data concerning the densification behavior of the ZnO/SiC composite system reported by De Jonghe et al. [L. C. De Jonghe, M. N. Rahaman, and C. H. Hsueh, Acta Metall. 34, 1467 (1986)]. The universal nature of this lattice for other composites is discussed with respect to site percolation theory. The application of this concept to powder compacts containing either whiskers or agglomerates is briefly discussed.

Thermal Shock Properties of Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 Composite Coatings

2011 ◽  
Vol 275 ◽  
pp. 47-50
Author(s):  
Asma Salman ◽  
Brian Gabbitas ◽  
De Liang Zhang
Keyword(s):  
Thermal Shock ◽  
Tool Steel ◽  
Thermal Shock Resistance ◽  
Composite Coatings ◽  
Composite Powders ◽  
H13 Tool Steel ◽  
Al2o3 Composite ◽  
Shock Resistance ◽  
Shock Behaviour ◽  
Thermal Shock Behaviour

Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings have a potential to reduce dissolution and aluminium soldering tendency of H13 tool steel used in the aluminium processing industry. The thermal shock resistance of H13 tool steel coated with Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite powders sprayed using a high velocity oxygen fuel (HVOF) technique was studied. The thermal shock behaviour of the composite coatings was investigated by subjecting the coated coupons to a number of cycles, each cycle consisting of a holding time of 30 seconds in molten aluminium at 700 ± 10 °C followed by quenching into water. The surfaces of the coupons were examined for Al soldering and an evaluation of surface spallation. Any cracks found in the coatings were studied to explain their thermal shock behaviour. The results of this study showed that both Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings on H13 tool steel have good thermal shock resistance with a thermal shock life between 300 to 400 cycles. The composite coatings and fracture surfaces were analyzed using scanning electron microscopy.

Synthesis of high-strength W–Ta ultrafine-grain composites

2008 ◽  
Vol 23 (1) ◽  
pp. 133-139 ◽  
Author(s):  
R.T. Ott ◽  
X.Y. Yang ◽  
D.E. Guyer ◽  
S. Chauhan ◽  
D.J. Sordelet
Keyword(s):  
High Strength ◽  
High Energy ◽  
High Temperature Phase ◽  
High Yield ◽  
Ultrafine Grain ◽  
Temperature Phase ◽  
Composite Powders ◽  
Ultrafine Grained ◽  
Submicron Scale ◽  
The Individual

Bulk samples of an ultrafine-grained tungsten–tantalum composite alloy have been synthesized by consolidating mechanically milled composite powders. The grain growth during densification is limited due to the submicron-scale layering of the individual metals in the composite particles and the relatively low sintering temperature (1300 °C). The ultrafine microstructure of the high-density (∼99% theoretical density) samples leads to a high yield stress of ∼3 GPa under quasi-static uniaxial compression. A tendency for Ta-rich solid-solution formation during densification was observed, and the high-temperature phase equilibria in the composite powders were examined further using high-energy x-ray diffraction at temperatures up to 1300 °C.

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