Influence of Rare Earth on Shape Memory and Martensitic Transformation Behaviors of a FeMnSiCr Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 1995-1998
Author(s):  
Xing Huang ◽  
Shipu Chen ◽  
T.Y. Hsu
Keyword(s):  
Rare Earth ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Stacking Faults ◽  
The Other ◽  
Strengthening Effect ◽  
Shape Memory Property ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Shockley Dislocation

Proper amount of blend rare earth (RE), e.g. less than 0.2 wt%, was added into a Fe25Mn6Si5Cr alloy and showed beneficial effect on its shape memory property. On the other hand, measurements of internal friction revealed that RE-addition reduces the Ms temperature and the amount of thermal-induced martensite. Higher La-content in thin hcp (e) plates than that in fcc (g) matrix was observed by analytical TEM. Thermodynamic calculations also indicated a relatively high equilibrated concentration in e and a strong interaction between La atom and 1/6<112> Shockley dislocation. Except for the grain refinement and solid-solution strengthening effect, the influence of RE on the g ® e martensitic transformation is discussed in taking into account both the Suzuki Effect and Suzuki Lock. The former results in a reduced stacking fault energy, while the Suzuki Lock hinders the movement of Shockley partials and thus the extension of stacking faults.

Characterization of the Superelasticity and the Martensitic Transformation from Ti-Nb-(O,N) Biomedical Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 1244-1249 ◽  
Author(s):  
Thierry Gloriant ◽  
Philippe Castany ◽  
Andry Ramarolahy ◽  
Pascal Laheute ◽  
Frédéric Prima ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Strong Influence ◽  
Tensile Tests ◽  
Strengthening Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

In this paper, results concerning newly developed Ti-Nb based superelastic alloys containing interstitial O or N element are presented. These elements were added because of their strong influence on the alpha” martensitic transformation and also because of their solid-solution strengthening effect. Microstructures and mechanical behavior of the alloys were investigated by different methods and compared with a binary Ti-Nb alloy taken as reference. On the other hand, in-situ synchrotron X-ray diffraction analyses during tensile tests have been specifically performed to characterize precisely the stress-induced martensitic transformation in such alloys.

scholarly journals Effect of Nd Addition on the Microstructure and Martensitic Transformation of Ni-Ti Shape Memory Alloys

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
M. Dovchinvanchig ◽  
C. W. Zhao ◽  
S. L. Zhao ◽  
X. K. Meng ◽  
Y. J. Jin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Earth Element ◽  
Transformation Behavior ◽  
Nd Addition ◽  
One Step ◽  
Niti Matrix ◽  
Start Temperature

The effect of rare earth element Nd addition on the microstructure and martensitic transformation behavior of Ni50Ti50−xNdx(x=0, 1, 3, 7, 20) shape memory alloy was investigated experimentally. The results showed that the microstructure of Ni-Ti-Nd ternary alloy consists of the NiNd phase and the NiTi matrix. One-step martensitic transformation was observed in all alloys. The martensitic transformation start temperatureMsincreased gradually with increasing Nd content for Ni-Ti-Nd alloys.

Mechanical Properties of Ga1–xInxAs

1985 ◽  
Vol 53 ◽  
Author(s):  
S. Guruswamy ◽  
J.P. Hirth ◽  
K.T. Faber
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Temperature ◽  
Strengthening Effect ◽  
Plateau Stress ◽  
Solid Solution Strengthening ◽  
Stress Region ◽  
Solution Strengthening ◽  
Concentration Levels ◽  
Undoped Gaas

ABSTRACTSubstantial solid solution strengthening of GaAs by In acting as InAs4 units has recently been predicted. This strengthening could account for the reduction of dislocation density in GaAs single crystals grown from the melt. High temperature hardness measurements up to 700ºC have been carried out on (100) GaAs and Ga0.9975 In0.0025 As wafers. Results show a significant strengthening effect in In—doped GaAs even at concentration levels of about 0.2 wt%. A temperature independent flow stress region is observed for both these alloys. The In—doped GaAs shows ahigher plateau stress level compared to the undoped GaAs. The results are consistent with the solid solution strengthening model.

scholarly journals Extra-high oxygen addition as a new strengthening strategy to overcome strength/ductility trade-off in fully biocompatible hexagonal titanium alloys

2020 ◽  
Vol 321 ◽  
pp. 05012
Author(s):  
Régis Poulain ◽  
Stéphanie Delannoy ◽  
Jean-Philippe Couzinié ◽  
Ivan Guillot ◽  
Emmanuel Clouet ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
High Oxygen ◽  
Dislocation Network ◽  
Strengthening Effect ◽  
Trade Off ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Oxygen Addition ◽  
Underlying Mechanisms ◽  
The One

A new titanium alloy family was developed aiming at creating a fully biocompatible alternative to titanium alloys currently on the dental implants market. Despite their hexagonal closepacked (HCP) single-phase structure, these Ti-Zr-O materials display an extremely interesting combination of properties. Zirconium is shown to be involved through a double contribution: on the one hand, a moderate but noticeable solid solution strengthening effect and on the other hand, a strong grain refinement. Therefore, the combination of both effects results in a beneficial strengthening of Ti-Zr-O alloys. However, the main remarkable aspect remains the outstanding hardening generated by extra high oxygen addition, occurring without any drop of ductility. The evolution of the dislocation network according to the oxygen content has been investigated to understand the underlying mechanisms in these Ti-Zr-O alloys, allowing to overcome the classical strength/ductility trade-off in commercial titanium alloys. Finally, the different perspectives of these findings in the field of biomedical and more generally in the field of titanium alloys are discussed.

The Influence of Secondary Phase on Impact Toughness of Alloyed Iron Aluminides

2020 ◽  
Vol 405 ◽  
pp. 145-150
Author(s):  
Martin Švec ◽  
Adam Hotař ◽  
Věra Vodičková ◽  
Vojtěch Keller
Keyword(s):  
Impact Toughness ◽  
Room Temperature ◽  
Volume Fraction ◽  
Fracture Behaviour ◽  
Secondary Phase ◽  
Iron Aluminides ◽  
The Other ◽  
Secondary Phases ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

The microstructure and fracture surfaces were investigated for five Fe3Al – based iron aluminides doped by different alloying elements (Nb, Zr + C, Cr) or without addition. Generally, iron aluminides are considered as brittle material at room temperature, therefore the type and distribution of secondary phases affect the fracture behaviour. The influence of present secondary phase particles on impact toughness at room temperature was evaluated in comparison to binary alloy. The type and the volume fraction of particles affect the value of impact toughness significantly – these values decrease with increasing volume fraction of precipitates. On the other hand, the solid solution strengthening improves impact toughness.

Martensitic Transformation and Microstructural Characteristics in Copper Based Shape Memory Alloys

2012 ◽  
Vol 510-511 ◽  
pp. 105-110 ◽  
Author(s):  
Osman Adiguzel
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Martensitic Transformations ◽  
Microstructural Characteristics ◽  
Shape Memory Property ◽  
Martensite Variant ◽  
Cooperative Movement ◽  
Β Phase

Martensitic transformations are first order solid state phase transitions and occur in the materials on cooling from high temperature. Shape memory effect is an unusual property exhibited by certain alloy systems, and based on martensitic transformation. The shape memory property is characterized by the recoverability of previously defined shape or dimension when they are subjected to variation of temperature. The shape memory effect is facilitated by martensitic transformation, and shape memory properties are intimately related to the microstructures of the materials. Martensitic transformations occur as martensite variant with the cooperative movement of atoms on {110}β - type plane of austenite matrix. Martensitic transformations have diffusionless character, and the atomic movement is confined to interatomic lengths in the materials. The basic factors which govern the martensitic transformation are Bain distortion and homogeneous shears. Copper based alloys exhibit this property in metastable β-phase field.

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