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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.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Tuning the temperature range of superelastic Ni-Ti alloys for elastocaloric cooling via thermal processing

Abstract Caloric cooling enlisting solid-state refrigerants is potentially a promising eco-friendly alternative to conventional cooling based on vapor compression. The most common refrigerant materials for elastocaloric cooling to date are Ni-Ti based superelastic shape memory alloys. Here, we have explored tuning the operation temperature range of Ni 50.8 Ti 49.2 for elastocaloric cooling. In particular, we have studied the effect of thermal treatments (a.k.a. aging) on the transformation temperature, superelasticity, and elastocaloric effects of Ni 50.8 Ti 49.2 shape memory alloy tubes. The isothermal compressive test revealed that the residual strain of thermally-treated Ni-Ti tubes at room temperature approaches zero as aging time is increased. Short-time aging treatment at 400 °C resulted in good superelasticity and elastocaloric cooling performance with a large tunable austenite finish ( A f ) temperature range of 24.7 °C, as determined from the A f temperature of the samples that were aged 5–120 min. The main reason of the property change is the formation of a different amount of Ni 4 Ti 3 precipitates in the NiTi matrix. Our findings show that it is possible to tailor the A f temperature range for development of cascade elastocaloric cooling systems by thermally treating a starting single composition Ni-Ti alloy.

36 MATERIALS SCIENCE↗
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↗
DOE OSTI2024

Analytically differentiable metrics for phase stability

Here, in this work, a long-established but sparsely documented method of obtaining semi-analytic derivatives of thermodynamic properties with respect to equilibrium conditions is briefly reviewed and rigorously derived. This procedure is then leveraged to construct general forms of derivatives of the residual driving force, a metric for measuring phase stability used in CALPHAD model optimization, with respect to overall system and individual phase compositions. Applied examples – calculating heat capacity in the Al-Fe system, thermodynamic factors in the Nb-V-W system, and residual driving force derivatives in the Ni-Ti system – demonstrate the versatility, accuracy, and extensibility of this method. Using the developed method, residual driving force gradients can be applied directly in CALPHAD model optimizers, as well as in materials design frameworks, to identify regions of phase stability with an efficient, gradient-based approach.

36 MATERIALS SCIENCE↗
DOE OSTI2021

A theoretical calculation of stacking fault energy of Ni alloys: The effects of temperature and composition

Combining cluster expansion (CE) method with one dimensional axial Ising model, this work investigated the effects of alloying elements and configurational variations due to temperature on the stacking fault energy (SFE) of FCC Ni binary alloys. Ensembles of large numbers of atomistic structures, each with more than ~400 atoms, were generated to consider sufficient long-range chemical disorder and temperature effects due to configurational entropy. Here, a Monte Carlo Metropolis algorithm was used to generate these structures, whose energies were then evaluated based on the effective cluster interactions obtained from CE. As a baseline, this work had shown the SFE of pure Ni and Al to be 127 mJ/m 2 and 137 mJ/m 2 , respectively, which agreed with the experimental values of 125 mJ/m 2 and 150 mJ/m 2 reported in the literature. Additions of Al, Ti, Cr and Co to pure Ni were found to decrease the SFE to different extents. Although temperature does not strongly influence the SFE of the FCC Ni-Al and Ni-Cr binary alloys, it can lead to significant changes to the SFE of the FCC Ni-Ti and Ni-Co alloys. While effects of temperature and composition on SFE observed in this work were calculated from binary Ni alloys, the general trends are nonetheless expected to be valid in the γ phase of multicomponent Ni superalloys.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Effect of post-deposition heat treatment on microstructure and mechanical properties of NASA HR-1 cold spray coatings

The primary goal of this work was to examine the impact of heat treatment on the evolution of microstructure and mechanical properties of NASA HR-1 cold spray coatings. Coatings were produced employing a high pressure cold spray system using N2 and He process gases and the effect of process gas and deposition temperature on the microstructure and mechanical properties of the coatings was examined. Microstructural characterization was performed using optical microscopy, scanning electron microscopy, micro X-ray computed tomography, and electron backscatter diffraction. NASA HR-1 coatings produced with He process gas exhibited improved plastic deformation and resulted in the lowest porosity compared to those deposited with N2 process gas. All coatings showed brittle failure with limited ductility in the as-deposited condition. Heat treatment of the NASA HR-1 cold spray coatings was performed at 550°C and 950°C for 1 h to improve the mechanical strength of the coatings. Heat treatment improved the particle bonding and enhanced the mechanical properties of the cold spray coatings. Heat treatment performed at 550°C resulted in higher mechanical strength of coatings, whereas the heat treatment performed at 950°C resulted in recrystallized microstructure and improved ductility of the coatings. However, heat treatment at 950°C resulted in forming the Eta (η) phase and Ni-Ti intermetallics in all the NASA HR-1 cold spray coatings. Here, the overall results suggest that using He as process gas contributed to reduced porosity and enhanced mechanical properties of the cold spray coatings.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Materials Data on TiNi3 by Materials Project

Ni3Ti is Uranium Silicide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with twelve equivalent TiNi12 cuboctahedra, edges with twenty-four NiTi4Ni8 cuboctahedra, faces with six equivalent TiNi12 cuboctahedra, and faces with twelve NiTi4Ni8 cuboctahedra. All Ti–Ni bond lengths are 2.55 Å. In the second Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with six equivalent TiNi12 cuboctahedra, corners with twelve NiTi4Ni8 cuboctahedra, edges with eighteen NiTi4Ni8 cuboctahedra, faces with eight TiNi12 cuboctahedra, and faces with twelve NiTi4Ni8 cuboctahedra. There are six shorter (2.55 Å) and six longer (2.57 Å) Ti–Ni bond lengths. There are six inequivalent Ni sites. In the first Ni site, Ni is bonded to four Ti and eight Ni atoms to form NiTi4Ni8 cuboctahedra that share corners with four equivalent TiNi12 cuboctahedra, corners with fourteen NiTi4Ni8 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with twelve NiTi4Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with sixteen NiTi4Ni8 cuboctahedra. There are four shorter (2.53 Å) and four longer (2.55 Å) Ni–Ni bond lengths. In the second Ni site, Ni is bonded to four Ti and eight Ni atoms to form NiTi4Ni8 cuboctahedra that share corners with four equivalent TiNi12 cuboctahedra, corners with fourteen NiTi4Ni8 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with twelve NiTi4Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with sixteen NiTi4Ni8 cuboctahedra. There are four shorter (2.53 Å) and two longer (2.55 Å) Ni–Ni bond lengths. In the third Ni site, Ni is bonded to four Ti and eight Ni atoms to form distorted NiTi4Ni8 cuboctahedra that share corners with twelve NiTi4Ni8 cuboctahedra, edges with eight TiNi12 cuboctahedra, edges with sixteen NiTi4Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with fourteen NiTi4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.47–2.62 Å. In the fourth Ni site, Ni is bonded to four Ti and eight Ni atoms to form distorted NiTi4Ni8 cuboctahedra that share corners with twelve equivalent NiTi4Ni8 cuboctahedra, edges with eight TiNi12 cuboctahedra, edges with sixteen NiTi4Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with fourteen NiTi4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.47–2.62 Å. In the fifth Ni site, Ni is bonded to four Ti and eight Ni atoms to form distorted NiTi4Ni8 cuboctahedra that share corners with twelve NiTi4Ni8 cuboctahedra, edges with eight TiNi12 cuboctahedra, edges with sixteen NiTi4Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with fourteen NiTi4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.47–2.62 Å. In the sixth Ni site, Ni is bonded to four Ti and eight Ni atoms to form NiTi4Ni8 cuboctahedra that share corners with four equivalent TiNi12 cuboctahedra, corners with fourteen NiTi4Ni8 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with twelve NiTi4Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with sixteen NiTi4Ni8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti2Ni by Materials Project

Ti2Ni crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded in a 12-coordinate geometry to six equivalent Ni atoms. All Ti–Ni bond lengths are 2.48 Å. In the second Ti site, Ti is bonded in a 2-coordinate geometry to two equivalent Ni atoms. Both Ti–Ni bond lengths are 2.59 Å. Ni is bonded in a 12-coordinate geometry to six Ti atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is alpha iridium vanadium-like structured and crystallizes in the trigonal P-3 space group. The structure is three-dimensional. there are three inequivalent Ti sites. In the first Ti site, Ti is bonded in a body-centered cubic geometry to eight Ni atoms. There are six shorter (2.50 Å) and two longer (2.66 Å) Ti–Ni bond lengths. In the second Ti site, Ti is bonded in a 8-coordinate geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.43–2.88 Å. In the third Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.51–2.73 Å. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a body-centered cubic geometry to eight Ti atoms. In the second Ni site, Ni is bonded in a 8-coordinate geometry to eight Ti and three equivalent Ni atoms. All Ni–Ni bond lengths are 2.73 Å. In the third Ni site, Ni is bonded in a distorted body-centered cubic geometry to eight Ti and one Ni atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is alpha iridium vanadium-like structured and crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are five inequivalent Ti sites. In the first Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.50–2.83 Å. In the second Ti site, Ti is bonded in a 8-coordinate geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.44–2.89 Å. In the third Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.51–2.81 Å. In the fourth Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.51–2.76 Å. In the fifth Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.50–2.71 Å. There are five inequivalent Ni sites. In the first Ni site, Ni is bonded in a 8-coordinate geometry to eight Ti atoms. In the second Ni site, Ni is bonded in a 8-coordinate geometry to eight Ti atoms. In the third Ni site, Ni is bonded in a 8-coordinate geometry to eight Ti atoms. In the fourth Ni site, Ni is bonded in a 8-coordinate geometry to eight Ti atoms. In the fifth Ni site, Ni is bonded in a distorted body-centered cubic geometry to eight Ti atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti3Ni by Materials Project

Ti3Ni is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ti is bonded to eight equivalent Ti and four equivalent Ni atoms to form TiTi8Ni4 cuboctahedra that share corners with twelve equivalent TiTi8Ni4 cuboctahedra, edges with eight equivalent NiTi12 cuboctahedra, edges with sixteen equivalent TiTi8Ni4 cuboctahedra, faces with four equivalent NiTi12 cuboctahedra, and faces with fourteen equivalent TiTi8Ni4 cuboctahedra. All Ti–Ti bond lengths are 2.78 Å. All Ti–Ni bond lengths are 2.78 Å. Ni is bonded to twelve equivalent Ti atoms to form NiTi12 cuboctahedra that share corners with twelve equivalent NiTi12 cuboctahedra, edges with twenty-four equivalent TiTi8Ni4 cuboctahedra, faces with six equivalent NiTi12 cuboctahedra, and faces with twelve equivalent TiTi8Ni4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti3Ni4 by Materials Project

Ni4Ti3 is delta Molybdenum Boride-like structured and crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Ti is bonded in a 9-coordinate geometry to nine Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.44–2.72 Å. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a 6-coordinate geometry to six equivalent Ti and eight Ni atoms. There are two shorter (2.52 Å) and six longer (2.92 Å) Ni–Ni bond lengths. In the second Ni site, Ni is bonded in a 8-coordinate geometry to six equivalent Ti and two equivalent Ni atoms. In the third Ni site, Ni is bonded in a 7-coordinate geometry to seven equivalent Ti and one Ni atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ti is bonded in a body-centered cubic geometry to eight equivalent Ni atoms. All Ti–Ni bond lengths are 2.59 Å. Ni is bonded in a body-centered cubic geometry to eight equivalent Ti atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is beta-prime cadmium gold structured and crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. Ti is bonded in a 8-coordinate geometry to eight equivalent Ni atoms. There are six shorter (2.56 Å) and two longer (2.78 Å) Ti–Ni bond lengths. Ni is bonded in a 12-coordinate geometry to eight equivalent Ti atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is beta-prime cadmium gold structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Ti sites. In the first Ti site, Ti is bonded in a 12-coordinate geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.52–3.05 Å. In the second Ti site, Ti is bonded in a 12-coordinate geometry to seven Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.56–2.67 Å. In the third Ti site, Ti is bonded in a 12-coordinate geometry to eight Ni atoms. There are a spread of Ti–Ni bond distances ranging from 2.51–3.06 Å. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a 12-coordinate geometry to eight Ti and four Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.68–2.74 Å. In the second Ni site, Ni is bonded in a 12-coordinate geometry to eight Ti and four Ni atoms. There are one shorter (2.62 Å) and three longer (2.74 Å) Ni–Ni bond lengths. In the third Ni site, Ni is bonded in a 12-coordinate geometry to seven Ti and two Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is Tetraauricupride structured and crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. Ti is bonded to eight equivalent Ni atoms to form a mixture of distorted corner, edge, and face-sharing TiNi8 cuboctahedra. There are a spread of Ti–Ni bond distances ranging from 2.61–2.65 Å. Ni is bonded to eight equivalent Ti atoms to form a mixture of distorted corner, edge, and face-sharing NiTi8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is Tetraauricupride structured and crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. Ti is bonded to four equivalent Ti and eight equivalent Ni atoms to form distorted TiTi4Ni8 cuboctahedra that share corners with twelve equivalent TiTi4Ni8 cuboctahedra, edges with eight equivalent TiTi4Ni8 cuboctahedra, edges with sixteen equivalent NiTi8Ni4 cuboctahedra, faces with eight equivalent NiTi8Ni4 cuboctahedra, and faces with ten equivalent TiTi4Ni8 cuboctahedra. All Ti–Ti bond lengths are 2.71 Å. There are a spread of Ti–Ni bond distances ranging from 2.59–2.71 Å. Ni is bonded to eight equivalent Ti and four equivalent Ni atoms to form distorted NiTi8Ni4 cuboctahedra that share corners with twelve equivalent NiTi8Ni4 cuboctahedra, edges with eight equivalent NiTi8Ni4 cuboctahedra, edges with sixteen equivalent TiTi4Ni8 cuboctahedra, faces with eight equivalent TiTi4Ni8 cuboctahedra, and faces with ten equivalent NiTi8Ni4 cuboctahedra. All Ni–Ni bond lengths are 2.70 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi is alpha iridium vanadium-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are nine inequivalent Ti sites. In the first Ti site, Ti is bonded in a 8-coordinate geometry to one Ti and eight equivalent Ni atoms. The Ti–Ti bond length is 2.63 Å. There are four shorter (2.55 Å) and four longer (2.65 Å) Ti–Ni bond lengths. In the second Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight equivalent Ni atoms. All Ti–Ni bond lengths are 2.59 Å. In the third Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight equivalent Ni atoms. All Ti–Ni bond lengths are 2.65 Å. In the fourth Ti site, Ti is bonded in a 10-coordinate geometry to two Ti and eight equivalent Ni atoms. The Ti–Ti bond length is 2.63 Å. All Ti–Ni bond lengths are 2.83 Å. In the fifth Ti site, Ti is bonded in a body-centered cubic geometry to eight equivalent Ni atoms. All Ti–Ni bond lengths are 2.46 Å. In the sixth Ti site, Ti is bonded in a 8-coordinate geometry to one Ti and eight equivalent Ni atoms. The Ti–Ti bond length is 2.63 Å. There are four shorter (2.55 Å) and four longer (2.65 Å) Ti–Ni bond lengths. In the seventh Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight equivalent Ni atoms. All Ti–Ni bond lengths are 2.59 Å. In the eighth Ti site, Ti is bonded in a 10-coordinate geometry to two Ti and eight equivalent Ni atoms. The Ti–Ti bond length is 2.63 Å. All Ti–Ni bond lengths are 2.83 Å. In the ninth Ti site, Ti is bonded in a body-centered cubic geometry to eight equivalent Ni atoms. All Ti–Ni bond lengths are 2.46 Å. Ni is bonded in a 8-coordinate geometry to eight Ti atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiNi by Materials Project

NiTi crystallizes in the hexagonal P6mm space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded to eight Ni atoms to form a mixture of distorted edge and corner-sharing TiNi8 hexagonal bipyramids. There are a spread of Ti–Ni bond distances ranging from 2.33–2.62 Å. In the second Ti site, Ti is bonded in a 8-coordinate geometry to three equivalent Ti and five Ni atoms. All Ti–Ti bond lengths are 2.60 Å. There are a spread of Ti–Ni bond distances ranging from 2.35–2.62 Å. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded to eight Ti atoms to form a mixture of edge and corner-sharing NiTi8 hexagonal bipyramids. In the second Ni site, Ni is bonded in a 8-coordinate geometry to five Ti and three equivalent Ni atoms. All Ni–Ni bond lengths are 2.60 Å.

36 MATERIALS SCIENCE↗