skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy

Authors:
; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1398633
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 132; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-07 09:19:43; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Miao, J., Slone, C. E., Smith, T. M., Niu, C., Bei, H., Ghazisaeidi, M., Pharr, G. M., and Mills, M. J. The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy. United States: N. p., 2017. Web. doi:10.1016/j.actamat.2017.04.033.
Miao, J., Slone, C. E., Smith, T. M., Niu, C., Bei, H., Ghazisaeidi, M., Pharr, G. M., & Mills, M. J. The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy. United States. doi:10.1016/j.actamat.2017.04.033.
Miao, J., Slone, C. E., Smith, T. M., Niu, C., Bei, H., Ghazisaeidi, M., Pharr, G. M., and Mills, M. J. Thu . "The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy". United States. doi:10.1016/j.actamat.2017.04.033.
@article{osti_1398633,
title = {The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy},
author = {Miao, J. and Slone, C. E. and Smith, T. M. and Niu, C. and Bei, H. and Ghazisaeidi, M. and Pharr, G. M. and Mills, M. J.},
abstractNote = {},
doi = {10.1016/j.actamat.2017.04.033},
journal = {Acta Materialia},
number = C,
volume = 132,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.actamat.2017.04.033

Citation Metrics:
Cited by: 6works
Citation information provided by
Web of Science

Save / Share:
  • The distribution of migration energies of vacancies and interstitials in Ni 0.5Fe 0.5has a region of overlap, an indication of their comparable mobility compared to pure Ni (indicated by dotted line), which will greatly facilitate the recombination of Frenkel pairs.
  • It has been shown that concentrated solid solution alloys possess unusual electronic, magnetic, transport, mechanical and radiation-resistant properties that are directly related to underlying chemical complexity. Because every atom experiences a different local atomic environment, the formation and migration energies of vacancies and interstitials in these alloys exhibit a distribution, rather than a single value as in a pure metal or dilute alloy. In this study, using ab initio calculations based on density functional theory and special quasirandom structure, we have characterized the distribution of defect formation energy and migration barrier in four Ni-based solid-solution alloys: Ni 0.5Co 0.5, Nimore » 0.5Fe 0.5, Ni 0.8Fe 0.2 and Ni 0.8Cr 0.2. As defect formation energies in finite-size models depend sensitively on the elemental chemical potential, we have developed a computationally efficient method for determining it which takes into account the global composition and the local short-range order. In addition we have compared the results of our ab initio calculations to those obtained from available embedded atom method (EAM) potentials. Our results indicate that the defect formation and migration energies are closely related to the specific atomic size in the structure, which further determines the elemental diffusion properties. In conclusion, different EAM potentials yield different features of defect energetics in concentrated alloys, pointing to the need for additional potential development efforts in order to allow spatial and temporal scale-up of defect and simulations, beyond those accessible to ab initio methods.« less
  • Coatings for superalloys for extended service in atmospheres at high temperature are of great interest at present. The addition of reactive elements (RE's) such as Hf to these coatings has a pronounced effect on their high-temperature oxidation resistance. A laser cladding technique was used to produce Ni-Al-Cr-Hf alloys with an extended solid solution of Hf in a near-stoichiometric Ni{sub 3}Al matrix. A 10 kW CO{sub 2} laser with mixed powder feed was used for the cladding process. Scanning electron microscope (SEM), transmission electron microscope (TEM), and scanning transmission electron microscope (STEM) were employed for studies of microstructural evolution of alloysmore » produced during the processes. Microstructural studies reveal the formation of dendrites with a solid solubility of about 11 to 14 wt pct Hf and also a eutectic structure. Convergent-beam techniques and x-ray spectroscopy have been applied to characterize the phases formed during cladding.« less
  • The welding characteristics of a commercial wrought alloy with a nominal composition of Ni-29Co-28Cr-2.75Si were investigated. Gas tungsten arc weldments with filler metal matching the chemistry of the alloy were found to have limited room-temperature ductility in the as-welded condition. Since welding is the main fabrication method of this alloy, the welding and postweld heat treatment (PWHT) characteristics were examined to provide guidelines for fabrication in the field. Metallographic evaluation revealed that the weld metal was characterized by the distribution of a continuous eutectic phase consisting primarily of (Si, Ti){sub x}Ni{sub y}. The continuous eutectic phase in the as-welded deposit,more » which caused poor ductility of the welds, was successfully reduced or removed with proper PWHT. The PWHT is necessary if cold forming of a weldment is required after welding or if adequate joint ductility is a design requirement. The recommended PWHT temperature is 1,050 C.« less
  • A systematic study of the effects of up to 1.1 at. % carbon on the mechanical properties and evolution of the dislocation substructure in a series of a high entropy alloys (HEA) based on Fe40.4Ni11.3Mn34.8Al7.5Cr6 is presented. Transmission electron microscopy (TEM), synchrotron X-ray diffraction (XRD) and atom probe tomography (APT) were used to show that all the alloys are single-phase f.c.c. random solid solutions. The lattice constant, determined from synchrotron XRD measurements, increases linearly with increasing carbon concentration, which leads to a linear relationship between the yield strength and the carbon concentration. The dislocation substructures, as determined by a TEM,more » show a transition from wavy slip to planar slip and, at higher strains, and from cell-forming structure (dislocations cells, cell blocks and dense dislocation walls) to non-cell forming structure (Taylor lattice, microbands and domain boundaries) with the addition of carbon, features related to the increase in lattice friction stress. The stacking fault energy (measured via weak-beam imaging of the separation of dislocation partials) decreases with increasing carbon content, which also contributes to the transition from wavy slip to planar slip. The formation of non-cell forming structure induced by carbon leads to a high degree of strain hardening and a substantial increase in the ultimate tensile strength. The consequent postponement of necking due to the high strain hardening, along with the plasticity accommodation arising from the formation of microbands and domain boundaries, result in an increase of ductility due to the carbon addition. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.« less