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16 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Metastable formation and disordering kinetics of body-centered orthorhombic CrNi 2 laths in a Cr-Ni binary alloy

Chromium (Cr) alloys combine low density with high-temperature strength but suffer from brittleness and rapid softening. Body-centered orthorhombic (BCO) CrNi 2 laths have been shown to improve Cr-alloy high-temperature strength retention, yet their thermal stability and transformation behavior remain unclear. CrNi 2 conventionally forms through long-range ordering from a face-centered cubic (FCC) phase. Using multiscale microscopy and neutron diffraction, we show that CrNi 2 instead nucleates from a body-centered cubic (BCC) matrix, in a binary Cr 85 Ni 15 alloy. Despite aging above the equilibrium ordering temperature, CrNi 2 persists for ∼220 h at 760 °C before fully disordering, indicating sluggish transformation kinetics. The formation and decomposition follow differing transformation pathways (BCC → CrNi 2 → FCC), revealing kinetic asymmetry not captured by equilibrium Cr-Ni phase diagrams. In conclusion, these findings redefine the transformation behavior of CrNi 2 , establish its metastable kinetic window, and suggest alloying strategies to stabilize CrNi 2 for precipitation strengthening of high-temperature Cr-alloys.

CrNi2 transformation kinetics↗
DOE OSTI2022

Theoretical antiferromagnetism of ordered face-centered cubic Cr-Ni alloys

Contrary to prior calculations, the Ni-rich ordered structures of the Cr-Ni alloy system are found to be antiferromagnetic under semilocal density-functional theory. The optimization of local magnetic moments significantly increases the driving force for the formation of CrNi 2 , the only experimentally observed intermetallic phase. This structure's ab initio magnetism appears well described by a Heisenberg Hamiltonian with longitudinal spin fluctuations; itinerant Cr moments are induced only by the strength of exchange interactions. The role of magnetism at temperature is less clear and several scenarios are considered based on a review of experimental literature, specifically a failure of the theory, the existence of an overlooked magnetic phase transition, and the coupling of antiferromagnetism to chemical ordering. In conclusion, implications for related commercial and high-entropy alloys are discussed for each case.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Analytical gradient-based optimization of CALPHAD model parameters

The calibration of CALPHAD (CALculation of PHAse Diagrams) models involves the solution of a very challenging high-dimensional multiobjective optimization problem. Traditional approaches to parameter fitting predominantly rely on gradient-free methods, which while robust, are computationally inefficient and often scale poorly with model complexity. In this work, we introduce and demonstrate a generalizable framework for analytic gradient-based optimization of the parameters of the CALPHAD model enabled by the recently formalized Jansson derivative technique. This method allows for efficient evaluation of gradients of thermodynamic properties at equilibrium with respect to model parameters, even in the presence of arbitrarily complex internal degrees of freedom. Leveraging these semi-analytic gradients, we employ the conjugate gradient (CG) method to optimize thermodynamic model parameters for four binary alloy systems: Cu-Mg, Fe-Ni, Cr-Ni, and Cr-Fe. Across all systems, CG achieves comparable or superior optimality relative to Bayesian ensemble Markov Chain Monte Carlo (MCMC) with improvements in computational efficiency ranging from one to three orders of magnitude. Furthermore, our results establish a new paradigm for CALPHAD assessments in which high fidelity data-rich model calibration becomes tractable using deterministic gradient-informed algorithms.

CALPHAD↗
DOE OSTI2020

Materials Data on CrNi2 by Materials Project

Ni2Cr crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Cr is bonded to two equivalent Cr and ten equivalent Ni atoms to form CrCr2Ni10 cuboctahedra that share corners with two equivalent CrCr2Ni10 cuboctahedra, corners with ten equivalent NiCr5Ni7 cuboctahedra, edges with twelve equivalent CrCr2Ni10 cuboctahedra, edges with twelve equivalent NiCr5Ni7 cuboctahedra, faces with four equivalent CrCr2Ni10 cuboctahedra, and faces with fourteen equivalent NiCr5Ni7 cuboctahedra. Both Cr–Cr bond lengths are 2.47 Å. There are two shorter (2.48 Å) and eight longer (2.49 Å) Cr–Ni bond lengths. Ni is bonded to five equivalent Cr and seven equivalent Ni atoms to form NiCr5Ni7 cuboctahedra that share corners with five equivalent CrCr2Ni10 cuboctahedra, corners with seven equivalent NiCr5Ni7 cuboctahedra, edges with six equivalent CrCr2Ni10 cuboctahedra, edges with eighteen equivalent NiCr5Ni7 cuboctahedra, faces with seven equivalent CrCr2Ni10 cuboctahedra, and faces with eleven equivalent NiCr5Ni7 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.46–2.50 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrNi3 by Materials Project

Ni3Cr is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cr is bonded to twelve Ni atoms to form CrNi12 cuboctahedra that share corners with four equivalent CrNi12 cuboctahedra, corners with eight equivalent NiCr4Ni8 cuboctahedra, edges with eight equivalent CrNi12 cuboctahedra, edges with sixteen equivalent NiCr4Ni8 cuboctahedra, faces with four equivalent CrNi12 cuboctahedra, and faces with fourteen NiCr4Ni8 cuboctahedra. There are four shorter (2.48 Å) and eight longer (2.50 Å) Cr–Ni bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded to four equivalent Cr and eight equivalent Ni atoms to form NiCr4Ni8 cuboctahedra that share corners with four equivalent NiCr4Ni8 cuboctahedra, corners with eight equivalent CrNi12 cuboctahedra, edges with twenty-four NiCr4Ni8 cuboctahedra, faces with six equivalent CrNi12 cuboctahedra, and faces with twelve NiCr4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.50 Å. In the second Ni site, Ni is bonded to four equivalent Cr and eight Ni atoms to form NiCr4Ni8 cuboctahedra that share corners with twelve equivalent NiCr4Ni8 cuboctahedra, edges with eight equivalent CrNi12 cuboctahedra, edges with sixteen NiCr4Ni8 cuboctahedra, faces with four equivalent CrNi12 cuboctahedra, and faces with fourteen NiCr4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrNi3 by Materials Project

Ni3Cr is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cr is bonded to twelve equivalent Ni atoms to form CrNi12 cuboctahedra that share corners with twelve equivalent CrNi12 cuboctahedra, edges with twenty-four equivalent NiCr4Ni8 cuboctahedra, faces with six equivalent CrNi12 cuboctahedra, and faces with twelve equivalent NiCr4Ni8 cuboctahedra. All Cr–Ni bond lengths are 2.51 Å. Ni is bonded to four equivalent Cr and eight equivalent Ni atoms to form NiCr4Ni8 cuboctahedra that share corners with twelve equivalent NiCr4Ni8 cuboctahedra, edges with eight equivalent CrNi12 cuboctahedra, edges with sixteen equivalent NiCr4Ni8 cuboctahedra, faces with four equivalent CrNi12 cuboctahedra, and faces with fourteen equivalent NiCr4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.51 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrNi3 by Materials Project

Ni3Cr is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cr is bonded in a distorted body-centered cubic geometry to fourteen Ni atoms. There are eight shorter (2.44 Å) and six longer (2.82 Å) Cr–Ni bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded in a distorted body-centered cubic geometry to four equivalent Cr and four equivalent Ni atoms. All Ni–Ni bond lengths are 2.44 Å. In the second Ni site, Ni is bonded in a 8-coordinate geometry to six equivalent Cr and eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr3Ni by Materials Project

Cr3Ni is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a distorted body-centered cubic geometry to four equivalent Cr and four equivalent Ni atoms. All Cr–Cr bond lengths are 2.49 Å. All Cr–Ni bond lengths are 2.49 Å. In the second Cr site, Cr is bonded in a 8-coordinate geometry to eight equivalent Cr and six equivalent Ni atoms. All Cr–Ni bond lengths are 2.88 Å. Ni is bonded in a distorted body-centered cubic geometry to fourteen Cr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr3Ni by Materials Project

Cr3Ni is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cr is bonded to eight equivalent Cr and four equivalent Ni atoms to form CrCr8Ni4 cuboctahedra that share corners with twelve equivalent CrCr8Ni4 cuboctahedra, edges with eight equivalent NiCr12 cuboctahedra, edges with sixteen equivalent CrCr8Ni4 cuboctahedra, faces with four equivalent NiCr12 cuboctahedra, and faces with fourteen equivalent CrCr8Ni4 cuboctahedra. All Cr–Cr bond lengths are 2.52 Å. All Cr–Ni bond lengths are 2.52 Å. Ni is bonded to twelve equivalent Cr atoms to form NiCr12 cuboctahedra that share corners with twelve equivalent NiCr12 cuboctahedra, edges with twenty-four equivalent CrCr8Ni4 cuboctahedra, faces with six equivalent NiCr12 cuboctahedra, and faces with twelve equivalent CrCr8Ni4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr3Ni by Materials Project

Cr3Ni is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Cr sites. In the first Cr site, Cr is bonded to eight equivalent Cr and four equivalent Ni atoms to form CrCr8Ni4 cuboctahedra that share corners with four equivalent CrCr8Ni4 cuboctahedra, corners with eight equivalent NiCr12 cuboctahedra, edges with twenty-four CrCr8Ni4 cuboctahedra, faces with six equivalent NiCr12 cuboctahedra, and faces with twelve CrCr8Ni4 cuboctahedra. All Cr–Cr bond lengths are 2.53 Å. All Cr–Ni bond lengths are 2.54 Å. In the second Cr site, Cr is bonded to eight Cr and four equivalent Ni atoms to form CrCr8Ni4 cuboctahedra that share corners with twelve equivalent CrCr8Ni4 cuboctahedra, edges with eight equivalent NiCr12 cuboctahedra, edges with sixteen CrCr8Ni4 cuboctahedra, faces with four equivalent NiCr12 cuboctahedra, and faces with fourteen CrCr8Ni4 cuboctahedra. All Cr–Cr bond lengths are 2.54 Å. All Cr–Ni bond lengths are 2.53 Å. Ni is bonded to twelve Cr atoms to form NiCr12 cuboctahedra that share corners with four equivalent NiCr12 cuboctahedra, corners with eight equivalent CrCr8Ni4 cuboctahedra, edges with eight equivalent NiCr12 cuboctahedra, edges with sixteen equivalent CrCr8Ni4 cuboctahedra, faces with four equivalent NiCr12 cuboctahedra, and faces with fourteen CrCr8Ni4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr4Ni by Materials Project

Cr4Ni crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. there are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a 8-coordinate geometry to two equivalent Cr and two equivalent Ni atoms. Both Cr–Cr bond lengths are 2.48 Å. Both Cr–Ni bond lengths are 2.46 Å. In the second Cr site, Cr is bonded in a distorted body-centered cubic geometry to eight Cr atoms. There are four shorter (2.44 Å) and two longer (2.50 Å) Cr–Cr bond lengths. Ni is bonded in a 12-coordinate geometry to four equivalent Cr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrNi3 by Materials Project

Ni3Cr crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cr is bonded to six equivalent Cr and six equivalent Ni atoms to form CrCr6Ni6 cuboctahedra that share corners with six equivalent CrCr6Ni6 cuboctahedra, corners with six equivalent NiNi12 cuboctahedra, edges with six equivalent CrCr6Ni6 cuboctahedra, edges with eighteen NiCr3Ni9 cuboctahedra, faces with six equivalent CrCr6Ni6 cuboctahedra, and faces with twelve equivalent NiCr3Ni9 cuboctahedra. All Cr–Cr bond lengths are 2.50 Å. All Cr–Ni bond lengths are 2.49 Å. There are five inequivalent Ni sites. In the first Ni site, Ni is bonded to three equivalent Cr and nine Ni atoms to form NiCr3Ni9 cuboctahedra that share corners with twelve equivalent NiCr3Ni9 cuboctahedra, edges with six equivalent CrCr6Ni6 cuboctahedra, edges with eighteen NiCr3Ni9 cuboctahedra, faces with six equivalent CrCr6Ni6 cuboctahedra, and faces with twelve NiCr3Ni9 cuboctahedra. There are six shorter (2.50 Å) and three longer (2.52 Å) Ni–Ni bond lengths. In the second Ni site, Ni is bonded to twelve Ni atoms to form NiNi12 cuboctahedra that share corners with six equivalent CrCr6Ni6 cuboctahedra, corners with six equivalent NiNi12 cuboctahedra, edges with six equivalent CrCr6Ni6 cuboctahedra, edges with eighteen NiCr3Ni9 cuboctahedra, and faces with eighteen NiCr3Ni9 cuboctahedra. All Ni–Ni bond lengths are 2.50 Å. In the third Ni site, Ni is bonded to three equivalent Cr and nine Ni atoms to form NiCr3Ni9 cuboctahedra that share corners with seventeen NiCr3Ni9 cuboctahedra, edges with six equivalent CrCr6Ni6 cuboctahedra, edges with sixteen NiCr3Ni9 cuboctahedra, faces with six equivalent CrCr6Ni6 cuboctahedra, and faces with fifteen NiCr3Ni9 cuboctahedra. All Ni–Cr bond lengths are 2.49 Å. There are six shorter (2.50 Å) and three longer (2.52 Å) Ni–Ni bond lengths. In the fourth Ni site, Ni is bonded to sixteen Ni atoms to form NiNi16 cuboctahedra that share corners with six equivalent CrCr6Ni6 cuboctahedra, corners with sixteen NiCr3Ni9 cuboctahedra, edges with six equivalent CrCr6Ni6 cuboctahedra, edges with eighteen NiCr3Ni9 cuboctahedra, and faces with thirty-four NiCr3Ni9 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.50–5.00 Å. In the fifth Ni site, Ni is bonded to three equivalent Cr and nine Ni atoms to form NiCr3Ni9 cuboctahedra that share corners with seventeen NiCr3Ni9 cuboctahedra, edges with six equivalent CrCr6Ni6 cuboctahedra, edges with sixteen NiCr3Ni9 cuboctahedra, faces with six equivalent CrCr6Ni6 cuboctahedra, and faces with fifteen NiNi16 cuboctahedra. All Ni–Cr bond lengths are 2.49 Å. All Ni–Ni bond lengths are 2.50 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr2Ni by Materials Project

Cr2Ni is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Cr is bonded to six equivalent Cr and six equivalent Ni atoms to form a mixture of edge, corner, and face-sharing CrCr6Ni6 cuboctahedra. All Cr–Cr bond lengths are 2.32 Å. All Cr–Ni bond lengths are 2.72 Å. Ni is bonded in a 12-coordinate geometry to twelve equivalent Cr and four equivalent Ni atoms. All Ni–Ni bond lengths are 2.84 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrNi by Materials Project

NiCr is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cr is bonded in a body-centered cubic geometry to eight equivalent Ni atoms. All Cr–Ni bond lengths are 2.51 Å. Ni is bonded in a body-centered cubic geometry to eight equivalent Cr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrNi2 by Materials Project

Ni2Cr is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Cr is bonded in a 12-coordinate geometry to four equivalent Cr and twelve equivalent Ni atoms. All Cr–Cr bond lengths are 2.87 Å. All Cr–Ni bond lengths are 2.75 Å. Ni is bonded to six equivalent Cr and six equivalent Ni atoms to form a mixture of face, edge, and corner-sharing NiCr6Ni6 cuboctahedra. All Ni–Ni bond lengths are 2.34 Å.

36 MATERIALS SCIENCE↗