Microstructures and Interfaces in Melt-Growth Al2O3-Ln2O3 Based Eutectic Composites

2006 ◽  
Vol 45 ◽  
pp. 1377-1384 ◽  
Author(s):  
Léo Mazerolles ◽  
N. Piquet ◽  
M.F. Trichet ◽  
Michel Parlier
Keyword(s):  
Fracture Toughness ◽  
Single Crystal ◽  
Room Temperature ◽  
Eutectic Composition ◽  
High Strength ◽  
Ternary Systems ◽  
Growth Conditions ◽  
Temperature Influence ◽  
Directionally Solidified ◽  
Orientation Relationships

Directionally solidified oxide eutectic ceramics were prepared from Al2O3, Ln2O3 and ZrO2 based binary or ternary systems. Their microstructures consist of continuous networks of single-crystal Al2O3 and oxide compounds (LnAlO3, Ln3Al5O12) which interpenetrate without grain boundaries. The outstanding stability of these microstructures gives rise to a high strength and creep resistance at high temperature. Influence of growth conditions on the morphology of the as-obtained microstructures was studied. Preferred growth directions, orientation relationships between phases and single-crystal homogeneity of specimen were revealed. Low residual stresses were measured in the binary eutectics and fracture toughness at room temperature was improved by the addition of zirconia at a eutectic composition in ternary systems.

Fracture toughness of a high-strength beryllium at room temperature and 300� C

1977 ◽  
Vol 12 (8) ◽  
pp. 1519-1526 ◽  
Author(s):  
M. W. Perra ◽  
I. Finnie
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
High Strength

Strengthening Mechanisms and Tribological Properties of Ultra-Hard AlMgB14 Based Composite Reinforced with TiB2

2020 ◽  
Vol 12 (6) ◽  
pp. 866-872
Author(s):  
Wen Liu ◽  
Chun-Yan Hao ◽  
Xu-Dong Zhao ◽  
Xiang-Jun Wang ◽  
Guo-Liang Shi
Keyword(s):  
Fracture Toughness ◽  
Friction And Wear ◽  
Room Temperature ◽  
High Strength ◽  
Strengthening Mechanisms ◽  
Interface Bonding ◽  
Dispersion Strengthening ◽  
Hard Phase ◽  
Phase Dispersion ◽  
Relative Hardness

AlMgB14–TiB2 composites with ideal structures are successfully prepared by field activated and pressure assisted synthesis. The effects of different TiB2 contents on the relative hardness and toughness of the composites were investigated. The results showed adding TiB2 could both increase the hardness of AlMgB14 and improve the fracture toughness. The TiB2 contributed more to the hardness than to the toughness. The microstructure analysis shows that the main toughening mechanisms of AlMgB14–TiB2 composites are hard phase dispersion strengthening, high-strength interface bonding and the high elastic modulus of TiB2. Therefore, reducing the particle size of TiB2 to nanoscale is an efficient way to improve the toughness and hardness. The results of friction and wear experiment at room temperature have shown that the addition of TiB2 into AlMgB14 enhances the abrasion–resistant property.

Relationship between Microstructure and Tensile Strength in the Directionally Solidified (23-27) at. % Al-Ni Alloys

2006 ◽  
Vol 510-511 ◽  
pp. 458-461 ◽  
Author(s):  
Y. Lu ◽  
H.C. Kim ◽  
Je Hyun Lee ◽  
Myung Hoon Oh ◽  
Dang Moon Wee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Eutectic Composition ◽  
Volume Fraction ◽  
Solidification Rate ◽  
Transgranular Fracture ◽  
Hypoeutectic Alloy ◽  
Directionally Solidified ◽  
Dendritic Microstructure ◽  
Ni Alloys ◽  
Two Phases

Directional or single crystal technique was applied to enhance the ductility, and two phases of γ (Ni) phase or β (NiAl) phase in γ‘(Ni3Al) matrix were also considered to increase the strength and ductility. In this study, directionally solidified rods were prepared at the solidification rate of 50µm/s in 23-27 at.% Al-Ni alloys, and tensile strengths of these rods were analyzed at room temperature. Directionally solidified samples showed the γ dendrite fibers formed in the Ni3Al matrix in the hypo eutectic composition of 23 at.% Al, the γ‘ single phase in the eutectic composition of 24.5 at. % Al, and the β dendrite fibers in the γ‘ matrix in the hyper eutectic compositions of 25, 26, 27 at.% Al. The hypoeutectic alloy including γ dendrites with γ‘ matrix exhibited a large elongation of over 70% with ductile transgranular fracture at room temperature. With increasing Al contents, the γ dendritic microstructure changed to the β dendrite in the γ‘ matrix, which resulted in decreasing the elongation by increasing the volume fraction of the brittle β dendrites in the ductile γ’ matrix.

Investigation of NiAl–TiB2in situcomposites

1997 ◽  
Vol 12 (4) ◽  
pp. 1083-1090 ◽  
Author(s):  
J. T. Guo ◽  
Z. P. Xing
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Tensile Yield Strength ◽  
Matrix Composites ◽  
Orientation Relationships ◽  
The Matrix ◽  
Atomically Flat ◽  
Nial Matrix

A hot-pressing aided exothermic synthesis (HPES) technique to fabricate NiAl matrix composites containing 0 and 20 vol.% TiB2 particles was developed. The conversion of mixtures of elements to the product was complete after processing, and TiB2 particles in the matrix were uniformly dispersed. The microstructure and interfaces were very thermally stable. The interfaces between NiAl and TiB2 were atomically flat, sharp, and generally free from interfacial phases. In some cases, however, thin amorphous layers existed at NiAl/TiB2 interfaces. At least three kinds of orientation relationships between TiB2 and NiAl were observed. The compressive yield strengths at room temperature and at 1000 °C of the composite were approximately three times as strong as those of the unreinforced NiAl. The tensile yield strength at 980 °C of the composite was about three times stronger than that of NiAl. The ambient fracture toughness of the composite was slightly greater than that of the monolithic NiAl.

Processing and Mechanical Properties of RuAl-Based Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 1469-1474 ◽  
Author(s):  
T.D. Reynolds ◽  
M. Acosta ◽  
David R. Johnson
Keyword(s):  
Fracture Toughness ◽  
Cyclic Oxidation ◽  
Room Temperature ◽  
Single Phase ◽  
Tensile Ductility ◽  
Tensile Behavior ◽  
Directionally Solidified ◽  
Two Phase ◽  
Heat Treated ◽  
Temperature Fracture

Alloys of Ru-Al-Cr with compositions between Ru-10Al-35Cr and Ru-3Al-39Cr (at.%) were directionally solidified and heat treated to produce single phase hcp-Ru(Cr,Al) and two phase B2-hcp microstructures. The room temperature fracture toughness, tensile behavior, and cyclic oxidation behavior at 1100°C were investigated and compared to previous results measured from RuAl and Ru-Al-Mo alloys. For microstructures consisting of a Ru(Cr,Al) matrix with fine RuAl precipitate, a good room temperature fracture toughness, tensile ductility, and oxidation resistance at 1100°C were measured.

ALUMINUM 712.0

Alloy Digest ◽  
1984 ◽  
Vol 33 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Room Temperature ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Aluminum Casting ◽  
Good Resistance ◽  
Aluminum Casting Alloy ◽  
Temperature Performance

Abstract ALUMINUM 712.0 is a high-strength aluminum casting alloy that is self aging at room temperature. It has good machinability, good dimensional stability and good resistance to corrosion and shock. Among its applications are marine castings, high-strength pressure-tight castings, aircraft components and cylinder heads. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness and fatigue. It also includes information on low and high temperature performance as well as casting, heat treating, machining, and joining. Filing Code: Al-249. Producer or source: Various aluminum companies.

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