Structural investigation of phase segregation in Mn 2 CrGa-based alloys

X. Z. Li, W. Y. Zhang, D. J. Sellmyer

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Alloys with nominal compositions of Mn 2 CrGa 1-x Al x (x = 0.0, 0.2, 0.5, 1.0) have been studied by X-ray powder diffraction (XRD). Detailed structural investigation of the alloys with x = 0.2 and 0.5 has been further carried out using transmission electron microscopy (TEM). The alloys, in the typical Heusler composition, were prepared using rapid quenching and subsequent annealing. The XRD analysis revealed that a disordered cubic phase was present in the alloys with x = 0.0 and 1.0 while a spinodal decomposition with phase separation has been observed in the alloys with x = 0.2 and 0.5. TEM study confirms a segregation of two crystalline phases, one of them a cubic phase with the β–Mn prototype structure and the other a new crystalline phase with a tetragonal structure. Energy-dispersive X-ray spectroscopy (EDS) analysis was used to determine the compositions of the two crystalline phases. The mass ratio of the tetragonal phase and the β–Mn prototype cubic phase is derived as t/c ≈ 2.41 by fitting the average compositions of the two crystalline phases to the nominal composition. The orientational relationship of two crystalline structures has been determined by selected-area electron diffraction (SAED) and stereogram analysis. The structures of the two crystalline phases have been investigated by high-resolution transmission electron microscopy (HRTEM) and image simulation. The structural model of the tetragonal phase is proposed and compared with the experimental results in SAED and HRTEM studies.

Original languageEnglish (US)
Pages (from-to)188-195
Number of pages8
JournalActa Materialia
Volume140
DOIs
StatePublished - Nov 2017

Fingerprint

Crystalline materials
Chemical analysis
High resolution transmission electron microscopy
Electron diffraction
X ray powder diffraction
Transmission electron microscopy
Rapid quenching
Spinodal decomposition
Phase separation
Energy dispersive spectroscopy
Annealing

Keywords

  • Electron diffraction
  • HRTEM
  • Heusler alloy
  • Mn CrGa
  • Spinodal decomposition

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

Structural investigation of phase segregation in Mn 2 CrGa-based alloys . / Li, X. Z.; Zhang, W. Y.; Sellmyer, D. J.

In: Acta Materialia, Vol. 140, 11.2017, p. 188-195.

Research output: Contribution to journalArticle

@article{47001327adc1497f95e33e18e55c91e1,
title = "Structural investigation of phase segregation in Mn 2 CrGa-based alloys",
abstract = "Alloys with nominal compositions of Mn 2 CrGa 1-x Al x (x = 0.0, 0.2, 0.5, 1.0) have been studied by X-ray powder diffraction (XRD). Detailed structural investigation of the alloys with x = 0.2 and 0.5 has been further carried out using transmission electron microscopy (TEM). The alloys, in the typical Heusler composition, were prepared using rapid quenching and subsequent annealing. The XRD analysis revealed that a disordered cubic phase was present in the alloys with x = 0.0 and 1.0 while a spinodal decomposition with phase separation has been observed in the alloys with x = 0.2 and 0.5. TEM study confirms a segregation of two crystalline phases, one of them a cubic phase with the β–Mn prototype structure and the other a new crystalline phase with a tetragonal structure. Energy-dispersive X-ray spectroscopy (EDS) analysis was used to determine the compositions of the two crystalline phases. The mass ratio of the tetragonal phase and the β–Mn prototype cubic phase is derived as t/c ≈ 2.41 by fitting the average compositions of the two crystalline phases to the nominal composition. The orientational relationship of two crystalline structures has been determined by selected-area electron diffraction (SAED) and stereogram analysis. The structures of the two crystalline phases have been investigated by high-resolution transmission electron microscopy (HRTEM) and image simulation. The structural model of the tetragonal phase is proposed and compared with the experimental results in SAED and HRTEM studies.",
keywords = "Electron diffraction, HRTEM, Heusler alloy, Mn CrGa, Spinodal decomposition",
author = "Li, {X. Z.} and Zhang, {W. Y.} and Sellmyer, {D. J.}",
year = "2017",
month = "11",
doi = "10.1016/j.actamat.2017.08.040",
language = "English (US)",
volume = "140",
pages = "188--195",
journal = "Acta Materialia",
issn = "1359-6454",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Structural investigation of phase segregation in Mn 2 CrGa-based alloys

AU - Li, X. Z.

AU - Zhang, W. Y.

AU - Sellmyer, D. J.

PY - 2017/11

Y1 - 2017/11

N2 - Alloys with nominal compositions of Mn 2 CrGa 1-x Al x (x = 0.0, 0.2, 0.5, 1.0) have been studied by X-ray powder diffraction (XRD). Detailed structural investigation of the alloys with x = 0.2 and 0.5 has been further carried out using transmission electron microscopy (TEM). The alloys, in the typical Heusler composition, were prepared using rapid quenching and subsequent annealing. The XRD analysis revealed that a disordered cubic phase was present in the alloys with x = 0.0 and 1.0 while a spinodal decomposition with phase separation has been observed in the alloys with x = 0.2 and 0.5. TEM study confirms a segregation of two crystalline phases, one of them a cubic phase with the β–Mn prototype structure and the other a new crystalline phase with a tetragonal structure. Energy-dispersive X-ray spectroscopy (EDS) analysis was used to determine the compositions of the two crystalline phases. The mass ratio of the tetragonal phase and the β–Mn prototype cubic phase is derived as t/c ≈ 2.41 by fitting the average compositions of the two crystalline phases to the nominal composition. The orientational relationship of two crystalline structures has been determined by selected-area electron diffraction (SAED) and stereogram analysis. The structures of the two crystalline phases have been investigated by high-resolution transmission electron microscopy (HRTEM) and image simulation. The structural model of the tetragonal phase is proposed and compared with the experimental results in SAED and HRTEM studies.

AB - Alloys with nominal compositions of Mn 2 CrGa 1-x Al x (x = 0.0, 0.2, 0.5, 1.0) have been studied by X-ray powder diffraction (XRD). Detailed structural investigation of the alloys with x = 0.2 and 0.5 has been further carried out using transmission electron microscopy (TEM). The alloys, in the typical Heusler composition, were prepared using rapid quenching and subsequent annealing. The XRD analysis revealed that a disordered cubic phase was present in the alloys with x = 0.0 and 1.0 while a spinodal decomposition with phase separation has been observed in the alloys with x = 0.2 and 0.5. TEM study confirms a segregation of two crystalline phases, one of them a cubic phase with the β–Mn prototype structure and the other a new crystalline phase with a tetragonal structure. Energy-dispersive X-ray spectroscopy (EDS) analysis was used to determine the compositions of the two crystalline phases. The mass ratio of the tetragonal phase and the β–Mn prototype cubic phase is derived as t/c ≈ 2.41 by fitting the average compositions of the two crystalline phases to the nominal composition. The orientational relationship of two crystalline structures has been determined by selected-area electron diffraction (SAED) and stereogram analysis. The structures of the two crystalline phases have been investigated by high-resolution transmission electron microscopy (HRTEM) and image simulation. The structural model of the tetragonal phase is proposed and compared with the experimental results in SAED and HRTEM studies.

KW - Electron diffraction

KW - HRTEM

KW - Heusler alloy

KW - Mn CrGa

KW - Spinodal decomposition

UR - http://www.scopus.com/inward/record.url?scp=85028300260&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85028300260&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2017.08.040

DO - 10.1016/j.actamat.2017.08.040

M3 - Article

AN - SCOPUS:85028300260

VL - 140

SP - 188

EP - 195

JO - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

ER -