Search NASA⌕ Search

SEARCH · Search NASA

Results for “Shape memory alloys”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Magnetic shape memory alloy Ni45Co5Mn36.6In13.4 measured on ARCS at 300 K and 450 K

These sqw files were generated by combining all of the individual crystal angles scans using the HORACE software package (https://pace-neutrons.github.io/Horace/unstable/user_guide/Getting_started.html). The neutron incident energy for both temperatures was 50 meV. The file labeled 50meV_450K_All.sqw is the 450 K data and the file labeled 50meV_RT_All.sqw is for the 300 K data. The crystal was oriented such that HHL is in the scattering plane.

excitations↗
DOE OSTI2024

Strain glass state of magnetic shape memory alloy Ni45Co5Mn36.6In13.4 measured on ARCS at 300 K

Combined inelastic neutron scattering data from ARCS on the strain glass state of Ni45Co5Mn36.6In13.4 measured at 300 K. Crystal was oriented with HHL in the scattering plane. To obtain a large Q-E volume the crystal was rotated in the beam and the individual angles were combined using the HORACE software package (https://pace-neutrons.github.io/Horace/unstable/user_guide/Getting_started.html).

excitations↗
DOE OSTI2024

Strain glass state of magnetic shape memory alloy Ni45Co5Mn36.6In13.4 measured on SEQUOIA at 5 K

Combined inelastic neutron scattering data from SEQUOIA on the strain glass state of Ni45Co5Mn36.6In13.4 measured at 5 K. Crystal was oriented with HHL in the scattering plane. To obtain a large Q-E volume the crystal was rotated in the beam and the individual angles were combined using the HORACE software package (https://pace-neutrons.github.io/Horace/unstable/user_guide/Getting_started.html).

excitations↗
DOE OSTI2024

Additively Manufacturing Nitinol Shape Memory Alloys for Advanced Actuator Designs

The objective of this research was to understand the role of feedstock production in the phase transformation behavior of additively manufactured Ni-Ti alloys for advanced actuator design. Industrial adoption of additively manufactured Ni-Ti alloys depends on the ability to produce repeatable phase transformation behavior, quantified here by the austenite to martensite transformation on heating. Small variations in the alloy composition may have a significant effect on the temperature at which this transformation occurs. This project showed that the powder characteristics play an important role in determining this behavior. Increases in the surface area per unit volume of the powder, either as a function of size distribution or morphology, have the effect of reducing the Ti content in the alloy through the formation of Ti-rich oxides on the powder surface, which has the effect of depressing the transformation temperature. Preferential Ni vaporization during additive manufacturing can partially offset this effect. To achieve repeatable results, it is important to understand the effect of powder oxidation, and to control the powder characteristics.

36 MATERIALS SCIENCE↗
NASA NTRS2010

Experiment and Modeling of Simultaneous Creep, Plasticity and Transformation of High Temperature Shape Memory Alloys During Cyclic Actuation

The present work is focused on studying the cycling actuation behavior of HTSMAs undergoing simultaneous creep and transformation. For the thermomechanical testing, a high temperature test setup was assembled on a MTS frame with the capability to test up to temperatures of 600 C. Constant stress thermal cycling tests were conducted to establish the actuation characteristics and the phase diagram for the chosen HTSMA. Additionally, creep tests were conducted at constant stress levels at different test temperatures to characterize the creep behavior of the alloy over the operational range. A thermodynamic constitutive model is developed and extended to take into account a) the effect of multiple thermal cycling on the generation of plastic strains due to transformation (TRIP strains) and b) both primary and secondary creep effects. The model calibration is based on the test results. The creep tests and the uniaxial tests are used to identify the viscoplastic behavior of the material. The parameters for the SMA properties, regarding the transformation and transformation induced plastic strain evolutions, are obtained from the material phase diagram and the thermomechanical tests. The model is validated by predicting the material behavior at different thermomechanical test conditions.

Kumar, Parikshith K.↗