In Situ Deformation in the T.E.M. on the two Phase Alloy Ti-24A1-9Nb First Results at Room Temperature

1994 ◽  
Vol 364 ◽  
Author(s):  
Marc Legros ◽  
Daniel Caillard ◽  
Alain Couret
Keyword(s):  
Room Temperature ◽  
Two Phase ◽  
Dislocation Glide ◽  
First Results ◽  
In Situ Deformation

AbstractIn situ deformation experiments have been performed on a two-phase Ti-23.7Al-9.4Nb (%at) alloy at room temperature. Dislocation glide processes in each phase are studied and discussed. An exemple of dislocation transmission through an interface is analysed in detail.

scholarly journals In situ deformation of nanocrystalline Al2O3 thin films at room temperature

2016 ◽  
pp. 195-196
Author(s):  
Erkka Frankberg ◽  
Lucile Joly-Pottuz ◽  
Francisco Garcia ◽  
Turkka Salminen ◽  
Thierry Douillard ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
In Situ Deformation

Microscopic study of the room temperature deformation mechanisms in β+γ' – (70 at.% Ni −30 at.% Al) in situ composite

1992 ◽  
Vol 50 (1) ◽  
pp. 912-913
Author(s):  
A. Misra ◽  
R. Gibala
Keyword(s):  
Microscopic Study ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Nominal Composition ◽  
Second Phase ◽  
Directionally Solidified ◽  
Ductile Phase ◽  
Two Phase ◽  
Room Temperature Ductility

Ductile phase reinforcement is an attractive approach for enhancing the room temperature ductility and toughness of brittle intermetallics such as β−NiAl. For example, a directionally solidified alloy of nominal composition 70 at.% Ni −30 at.% Al, having a two-phase β (brittle matrix) and γ (ductile second phase) microstructure, exhibits up to 9% tensile ductility at room temperature [1]. In the present investigation, a microscopic study has been made to understand the mechanisms involved in the ductility enhancement of the β + γ composite.

Superplasticity in Nb3Al/Nb In Situ Composites

1999 ◽  
Vol 601 ◽  
Author(s):  
S. Hanada ◽  
W. Fang
Keyword(s):  
Superplastic Deformation ◽  
Grain Boundary Sliding ◽  
Al Alloy ◽  
Two Phase ◽  
Dislocation Glide ◽  
In Situ Composite ◽  
Al Content ◽  
Boundary Sliding ◽  
Equiaxed Grains

AbstractMicrostructures of a binary Nb-15.8at%Al alloy ingot were controlled by isothermal forging and heat treatment to produce equiaxed, fine grains of Nb3Al and Nb solid solution (Nb33). Nb3Al/Nb33 two phase alloy (in-situ composite) is found to exhibit superplasticity especially when one of the constituent phases, Nb33, is supersaturated. During superplastic deformation Nb33 transforms to Nb3Al, and Al content in Nb33 decreases. After superplastic deformation the microstructure consisting of equiaxed grains is left unchanged, although a slight grain growth is observed. It is suggested that stress induced by grain boundary sliding is effectively accommodated through dislocation glide and climb in the soft Nb33

Microstructures and Mechanical Properties of NiAl+Mo In-Situ Eutectic Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
P. R. Subramanian ◽  
M. G. Mendiratta ◽  
D. B. Miracle ◽  
D. M. Dimiduk
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Room Temperature ◽  
Composite System ◽  
Elevated Temperatures ◽  
Two Phase ◽  
Structural Applications ◽  
Temperature Fracture

AbstractThe quasibinary NiAI-Mo system exhibits a large two-phase field between NiAl and the terminal (Mo) solid solution, and offers the potential for producing in-situ eutectic composites for high-temperature structural applications. The phase stability of this composite system was experimentally evaluated, following long-term exposures at elevated temperatures. Bend strengths as a function of temperature and room-temperature fracture toughness data are presented for selected NiA1-Mo alloys, together with results from fractography observations.

Study of Micromechanical Behaviour of Two Phase Polycrystalline Materials Using Diffraction and Self Consistent Model

2014 ◽  
Vol 783-786 ◽  
pp. 2059-2064
Author(s):  
Andrzej Baczmański ◽  
Elżbieta Gadalińska ◽  
Chedly Braham ◽  
Sebastian Wroński ◽  
Lea le Joncour ◽  
...  
Keyword(s):  
Lattice Strain ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Consistent Model ◽  
Self Consistent ◽  
In Situ Deformation ◽  
Specific Orientation

Diffraction methods for lattice strain measurement provide useful information concerning the nature of grains behaviour during elastoplastic deformation. The main advantage of the diffraction methods is the possibility of studying mechanical properties of polycrystalline materials separately in each phase and in groups of grains with a specific orientation. In this work we present application of the neutron and X-ray diffraction to study “in situ” deformation of two phase stainless steels during tensile loading. The experimental results are compared with self-consistent model.

Microstructures and Mechanical Behavior of Two-Phase Niobium Silicide-Niobium Alloys

1988 ◽  
Vol 133 ◽  
Author(s):  
M. G. Mendiratta ◽  
D. M. Dimiduk
Keyword(s):  
Mechanical Behavior ◽  
Phase Transformations ◽  
Room Temperature ◽  
Volume Fraction ◽  
Two Phase ◽  
Niobium Alloys ◽  
Intermetallic Matrix ◽  
Two Phases ◽  
The Individual

ABSTRACTIn the Nb-Si system, it is possible to produce in-situ composites consisting of a brittle Nb5Si3 intermetallic matrix and ductile Nb particles. The two phases are thermochemically stable up to ∼ 1500∼C and are amenable to wide microstructural variations including morphology, volume fraction, and the size of the individual microconstituents. This paper presents microstructures and phase transformations in these composites as a function of composition and heat treatments and bend properties from room-temperature to 1400°C.

In-situ observation of Nb/Nb5Si3 two-phase alloys during bending at various temperatures

2011 ◽  
Vol 1295 ◽  
Author(s):  
Seiji Miura ◽  
Yukiyoshi Tsutsumi ◽  
Tetsuo Mohri
Keyword(s):  
Plastic Deformation ◽  
Laser Scanning ◽  
Room Temperature ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
In Situ Observation ◽  
Two Phase ◽  
Crack Propagation Velocity ◽  
Deformation And Fracture

ABSTRACTIn order to understand the deformation and fracture behavior of Nb-Si alloys, in-situ observation was conducted during bending of small specimens at room and high temperatures. Nb-Si alloy ingots containing 18.1 at.%Si, 1.5 at.%Zr and 100 ppmMg were prepared by arc melting, followed by uni-axial solidification in an optical floating zone apparatus and a heat-treatment to obtain Nb/Nb5Si3 two-phase microstructure. Chevron-notched specimens with a dimension of 1x2x10mm were used for in-situ observation of bending tests under a confocal laser scanning microscope (CLSM) at room temperature and at 1140 °C. At room temperature the Nb-Si alloy shows a fracture toughness of 8 MPa m1/2 and the crack propagation velocity seems to be not uniform, presumably due to the ductile Nb. At 1140 °C the toughness of the alloy was about 20 MPa m1/2 and slower plastic deformation prior to the cracking was observed. The SEM observation of crack surfaces revealed that plastic deformation of Nb enhances the toughness of the alloy.

Thermally Activated Processes and Dislocation Mobilities in Two-Phase γ-Titanium Aluminides

1994 ◽  
Vol 364 ◽  
Author(s):  
Fritz Appel ◽  
Ulf Sparka ◽  
Richard Wagner
Keyword(s):  
Room Temperature ◽  
Titanium Aluminides ◽  
Dislocation Climb ◽  
Ductile Material ◽  
Material Behaviour ◽  
Two Phase ◽  
Dislocation Glide ◽  
Thermally Activated ◽  
Deformation Tests ◽  
Lattice Friction

AbstractThe processes controlling the dislocation mobility in two-phase γ-titanium aluminides have been investigated over a wide temperature range by determining the activation volumes and activation energies of thermally activated dislocation glide processes. The deformation tests are supplemented by electron microscope observations. Accordingly, at room temperature the mobility of ordinary dislocations is determined by a combination of localized pinning and lattice friction. Additional glide resistance arises from dislocation dipoles and debris defects, which are trailed and terminated at jogs in 1/2 <110] screw dislocations. Dislocation climb processes start above 900 K and seem to initiate the transition from brittle to ductile material behaviour.

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