Stress-strain behavior and shape memory effect in powder metallurgy TiNi alloys

1994 ◽  
Vol 42 (4) ◽  
pp. 1351-1358 ◽  
Author(s):  
H. Kato ◽  
T. Koyari ◽  
M. Tokizane ◽  
S. Miura
Keyword(s):  
Powder Metallurgy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stress Strain ◽  
Strain Behavior

scholarly journals NiMn-Based Metamagnetic Shape Memory Alloys

2009 ◽  
Vol 635 ◽  
pp. 23-31 ◽  
Author(s):  
Ryosuke Kainuma ◽  
K. Ito ◽  
W. Ito ◽  
R.Y. Umetsu ◽  
T. Kanomata ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Powder Metallurgy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Parent Phase ◽  
Martensite Phase ◽  
Ternary Alloys ◽  
Plasma Sintering ◽  
Spark Plasma

The magnetic properties of the parent and martensite phases of the Ni2Mn1+xSn1-x and Ni2Mn1+xIn1-x ternary alloys and the magnetic field-induced shape memory effect obtained in NiCoMnIn alloys are reviewed, and our recent work on powder metallurgy performed for NiCoMnSn alloys is also introduced. The concentration dependence of the total magnetic moment for the parent phase in the NiMnSn alloys is very different from that in the NiMnIn alloys, and the magnetic properties of the martensite phase with low magnetization in both NiMnSn and NiMnIn alloys has been confirmed by Mössbauer examination as being paramagnetic, but not antiferromagnetic. The ductility of NiCoMnSn alloys is drastically improved by powder metallurgy using the spark plasma sintering technique, and a certain degree of metamagnetic shape memory effect has been confirmed.

scholarly journals On the Free Recovery Bending Shape Memory Effect in Powder Metallurgy FeMnSiCrNi

2021 ◽  
Vol 44 (3) ◽  
pp. 5-11
Author(s):  
Lenuța CIURCĂ ◽  
Bogdan PRICOP ◽  
Mihai POPA ◽  
Victor Daniel APOSTOL ◽  
Leandru-Gheorghe BUJOREANU
Keyword(s):  
Powder Metallurgy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Protective Atmosphere ◽  
Training Procedure ◽  
Mechanically Alloyed ◽  
Deformation Degree ◽  
Alloy Particles ◽  
Air Gun

This paper presents the results of an original experimental study on the training capacity of a powder metallurgy (PM) FeMnSiCrNi shape memory alloy (SMA). The specimens were sintered under protective atmosphere from blended elemental powders, 50 vol.%. of alloy particles being mechanically alloyed. Lamellar specimens, hot rolled to 1 mm thickness, were bent against cylindrical calibres with five decreasing radii, to induce cold shapes with higher and higher deformation degree, as compared to the straight hot shape. During the training procedure, bent specimens were heated with a hot air gun, and developed free-recovery shape memory effect (SME) and partially deflected, by reducing their curvature. The first set of experiments involved fastening the specimens at one end, heating it and monitoring free end’s displacement by means of cinematographic analysis. Within the second set of experiments, both cold and hot shapes were recorded and digitalized and their chord’s length (b) and circle segment height (a) were measured and the radius was determined as R = a/2 + b2/8a for the cold (Rc) and hot shapes (Rh). Finally, the shape recovery degree was calculated for the nth calibre as Δrecn = (Rhn-Rrn)/(Rhn-1-Rrn) and the variation of Δrecn with calibre’s radius was discussed.

The Thermomechanical Modeling for Shape Memory Alloys

2011 ◽  
Vol 672 ◽  
pp. 195-199
Author(s):  
Diana C. Cirstea ◽  
Mariana Lucaci ◽  
Doina Raducanu ◽  
Violeta Tsakiris
Keyword(s):  
Constitutive Equation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phenomenological Models ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Recovery Stress ◽  
Stress Strain ◽  
Reasonable Approach ◽  
Thermomechanical Modeling

The shape memory alloys are materials that can change their shape by applying thermomechanical treatments. In order to design SMA materials, the stress-strain-temperature relationship is necessary. Modeling the constitute behavior of these materials supposes a few phenomenological models that can provide a quick and reasonable approach to assess the behavior of SMA. The proposed constitutive equation expresses well the properties of the shape memory effect, pseudoelasticity and recovery stress.

Tensile Failure of 55-Nitinol Wire

1975 ◽  
Vol 33 ◽  
pp. 46-47
Author(s):  
F. I. Grace
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stoichiometric Composition ◽  
Tensile Failure ◽  
Initial State ◽  
Initial Shape ◽  
Nitinol Wire ◽  
Cscl Type ◽  
Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

Sign in / Sign up

Export Citation Format

Share Document