HREM study of the matrix-pirecipitate interface structure and deformation mechanisms in a cobalt based superalloy

1991 ◽  
Vol 1 (6) ◽  
pp. 1015-1024 ◽  
Author(s):  
J.-M. Penisson
Keyword(s):  
Interface Structure ◽  
Deformation Mechanisms ◽  
The Matrix

scholarly journals Study of the Microstructure and Crack Evolution Behavior of Al-5Fe-1.5Er Alloy

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 172 ◽  
Author(s):  
Ming Li ◽  
Zhiming Shi ◽  
Xiufeng Wu ◽  
Huhe Wang ◽  
Yubao Liu
Keyword(s):  
Electron Microscopy ◽  
Crack Initiation ◽  
Tensile Tests ◽  
Eutectic Structure ◽  
Interface Structure ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Evolution Behavior

In this work, the microstructure of Al-5Fe-1.5Er alloy was characterized and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. The effect of microstructure on the behavior of crack initiation and propagation was investigated using in situ tensile testing. The results showed that when 1.5 wt.% Er was added in the Al-5Fe alloy, the microstructure consisted of α-Al matrix, Al3Fe, Al4Er, and Al3Fe + Al4Er eutectic phases. The twin structure of Al3Fe phase was observed, and the twin plane was {001}. Moreover, a continuous concave and convex interface structure of Al4Er was observed. Furthermore, Al3Fe was in the form of a sheet with a clear gap inside. In situ tensile tests of the alloy at room temperature showed that the crack initiation mainly occurred in the Al3Fe phase, and that the crack propagation modes included intergranular and trans-granular expansions. The crack trans-granular expansion was due to the strong binding between Al4Er phases and surrounding organization, whereas the continuous concave and convex interface structure of Al4Er provided a significant meshing effect on the matrix and the eutectic structure.

Precipitate Structure in an Alumina Dispersion-Strengthened Copper Base Composite Layer

2010 ◽  
Vol 152-153 ◽  
pp. 634-638
Author(s):  
Bao Hong Tian ◽  
Xiao Hong Chen ◽  
Yi Zhang ◽  
Yong Liu
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Composite Layer ◽  
Lattice Parameter ◽  
Interface Structure ◽  
Parameter Mismatch ◽  
Direction Parallel ◽  
Transmission Electron ◽  
The Matrix ◽  
Α Al2o3

A dilute copper alloy of Cu-0.45wt%Al -0.066wt %Y was selected to fabricate nanometer size Al2O3 particles dispersion-hardened composite layer by using aluminizing-internal oxidation technique. The structure and size of the precipitate, interface structure, lattice parameter mismatch and morphology were investigated by means of high resolution transmission electron microscope, analytical transmission electron microscope and image processing by VEC software. Results show that two different size and structure nano-alumina precipitate were identified as α-Al2O3 and γ-Al2O3 respectively during different processing. The precipitates possess semi-coherence or coherence interface structure to matrix with typical loop-loop contrast. The cubic γ-Al2O3 precipitate in certain crystal plane and direction parallel to the matrix。

The Location and Extent of Exfoliation of Clay on the Fracture Mechanisms in Nylon 66-Based Ternary Nanocomposites

2008 ◽  
Vol 8 (4) ◽  
pp. 1901-1912 ◽  
Author(s):  
Aravind Dasari ◽  
Zhong-Zhen Yu ◽  
Yiu-Wing Mai ◽  
Mingshu Yang
Keyword(s):  
Matrix Material ◽  
Deformation Mechanisms ◽  
Fracture Mechanisms ◽  
Nylon 66 ◽  
The Matrix ◽  
Negative Effect ◽  
Primary Focus ◽  
Dynamic Loading Conditions ◽  
Toughness Enhancement ◽  
Static And Dynamic Loading

The primary focus of this work is to elucidate the location and extent of exfoliation of clay on fracture (under both static and dynamic loading conditions) of melt-compounded nylon 66/clay/SEBS-g-MA ternary nanocomposites fabricated by different blending sequences. Distinct microstructures are obtained depending on the blending protocol employed. The state of exfoliation and dispersion of clay in nylon 66 matrix and SEBS-g-MA phase are quantified and the presence of clay in rubber is shown to have a negative effect on the toughness of the nanocomposites. The level of toughness enhancement of ternary nanocomposites depends on the blending protocol and the capability of different fillers to activate the plastic deformation mechanisms in the matrix. These mechanisms include: cavitation of SEBS-g-MA phase, stretching of voided matrix material, interfacial debonding of SEBS-g-MA particles, debonding of intercalated clay embedded inside the SEBS-g-MA phase, and delamination of intercalated clay platelets. Based on these results, new insights and approaches for the processing of better toughened polymer ternary nanocomposites are discussed.

Annealing simulations to determine the matrix interface structure of SiC quantum dots embedded in SiO2

2010 ◽  
Vol 7 (2) ◽  
pp. 407-410 ◽  
Author(s):  
Jan M. Knaup ◽  
Márton Vörös ◽  
Peter Déak ◽  
Adam Gali ◽  
Thomas Frauenheim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Interface Structure ◽  
Matrix Interface ◽  
The Matrix

Influences of interface structure on tribological properties of engineering polymer blends: a review

2020 ◽  
Vol 40 (8) ◽  
pp. 629-636
Author(s):  
Song Chen ◽  
Lei Wei ◽  
Bingxue Cheng ◽  
Yongliang Jin ◽  
Haitao Duan
Keyword(s):  
Polymer Blends ◽  
Tribological Properties ◽  
Interface Structure ◽  
Matrix Phase ◽  
Key Factors ◽  
Friction Process ◽  
The Matrix ◽  
Interfacial Compatibility ◽  
Recent Trends

AbstractPolymer blends have been widely used as tribological materials for replacements of traditional metals and ceramics. Polymer blends consist of the reinforced phase, the matrix phase and interfaces between reinforced and matrix phase. Although the interface structure of polymer blends is usually small in size, it is one of the key factors for deciding the physical and tribological properties of polymer blends. Thus, this review highlights the most recent trends in the field of influences of interface structure on tribological properties of engineering polymer blends. Emphasis is given to the improvement methods of interfacial compatibility of polymer blends and the behavior variation of interface structure during friction process.

Deformation Mechanisms in TiAl-Based Alloys Containing Low Oxygen

1990 ◽  
Vol 213 ◽  
Author(s):  
S. Sriram ◽  
Vijay K. Vasudevan ◽  
Dennis M. Dimiduk
Keyword(s):  
Analytical Electron Microscopy ◽  
Deformation Mechanisms ◽  
Low Oxygen ◽  
Weak Beam ◽  
Transmission Electron ◽  
Heat Treated ◽  
Analytical Electron ◽  
The Matrix ◽  
Recent Developments ◽  
High Purity Alloy

ABSTRACTThe effects of oxygen on the deformation behavior of Ti-(48-52)Al alloys is reported. Two types of studies were conducted. In the first, high purity alloy buttons containing low oxygen (~250 ppm) were prepared, whereas in the second, alloys with additions of 1 at.% Er to scavenge the oxygen from the matrix were prepared. The alloys were heat treated to produce large grains and the microstructures characterized by analytical electron microscopy. Samples prepared from the heat treated alloys were electropolished and deformed in compression to a plastic strain of 1.0-1.5% at temperatures between 25 and 800°C and the yield stress measured. The morphology of deformation, that is, slip lines and the presence of twinning, was studied by optical microscopy and the dislocation structures were characterized by weak-beam imaging in the transmission electron microscope. The results of these various studies are presented and discussed in terms of recent developments regarding the factors that appear to control the dislocation structure and the mobility of dislocations.

Interface structure and deformation mechanisms of AlN/GaN multilayers

2020 ◽  
Vol 46 (8) ◽  
pp. 11556-11562 ◽  
Author(s):  
Haitao Li ◽  
Henggao Xiang ◽  
Hongzhi Huang ◽  
Ziwen Zeng ◽  
Xianghe Peng
Keyword(s):  
Interface Structure ◽  
Deformation Mechanisms

scholarly journals Interface Structure and Mechanical Properties of 7075Al Hybrid Composite Reinforced with Micron Ti Metal Particles Using Pressure Infiltration

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 763 ◽  
Author(s):  
Yixiong Liu ◽  
Zhenxing Zheng ◽  
Genghua Cao ◽  
Dezhi Zhu ◽  
Chao Yang ◽  
...  
Keyword(s):  
Interface Structure ◽  
Mutual Diffusion ◽  
Metal Particles ◽  
Misfit Stress ◽  
Pressure Infiltration ◽  
Molten Aluminum Alloy ◽  
The Matrix ◽  
Solidification Processes ◽  
Strength And Plasticity ◽  
Reaction Activation Energy

Micron Ti metal particles were incorporated into SiCp/7075Al composites using pressure infiltration. The interface structure between the Ti metal particles and the matrix during the casting processes were investigated. Results show that the dispersed unreacted Ti particles form mutual diffusion layer at the interface without the formation of low-temperature intermetallic phases during the solidification processes. The interaction between the micron Ti and the molten aluminum alloy is subject to the mutual diffusion coefficient of Ti–Al rather than the reaction activation energy. The tensile strength and plasticity of the composite were improved simultaneously due to the high interfacial bonding strength and released thermal misfit stress cause by the incorporated Ti metal particles.

scholarly journals Co-introduction of precipitate hardening and TRIP in a TWIP high-entropy alloy using friction stir alloying

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tianhao Wang ◽  
Shivakant Shukla ◽  
Bharat Gwalani ◽  
Subhasis Sinha ◽  
Saket Thapliyal ◽  
...  
Keyword(s):  
Current Approach ◽  
Deformation Mechanisms ◽  
Engineering Properties ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Friction Stir ◽  
The Matrix ◽  
Face Centered ◽  
Multiple Deformation

AbstractTuning deformation mechanisms is imperative to overcome the well-known strength-ductility paradigm. Twinning-induced plasticity (TWIP), transformation-induced plasticity (TRIP) and precipitate hardening have been investigated separately and have been altered to achieve exceptional strength or ductility in several alloy systems. In this study, we use a novel solid-state alloying method—friction stir alloying (FSA)—to tune the microstructure, and a composition of a TWIP high-entropy alloy by adding Ti, and thus activating site-specific deformation mechanisms that occur concomitantly in a single alloy. During the FSA process, grains of the as-cast face-centered cubic matrix were refined by high-temperature severe plastic deformation and, subsequently, a new alloy composition was obtained by dissolving Ti into the matrix. After annealing the FSA specimen at 900 °C, hard Ni–Ti rich precipitates formed to strengthen the alloy. An additional result was a Ni-depleted region in the vicinity of newly-formed precipitates. The reduction in Ni locally reduced the stacking fault energy, thus inducing TRIP-based deformation while the remaining matrix still deformed as a result of TWIP. Our current approach presents a novel microstructural architecture to design alloys, an approach that combines and optimizes local compositions such that multiple deformation mechanisms can be activated to enhance engineering properties.

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