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Title: A study of microstructural evolution of Fe-18Cr-8Ni, Fe-17Cr-12Ni, and Fe-20Cr-25Ni stainless steels after mechanical alloying and annealing

Abstract

In this study, high-energy mechanical alloying technique was used to produce nanocrystalline stainless steels of three different compositions from elemental powders. The microstructural evolution (grain growth and phase transformation) as a function of alloy compositions and annealing temperatures were investigated by room and high temperature x-ray diffraction experiments, transmission electron microscopy and focused ion beam microscopy. The results revealed that stainless steels with low nickel content (i.e., Fe-18Cr-8Ni) underwent a deformation-induced martensitic transformation during room temperature mechanical alloying. Deformation-induced martensitic transformation with increasing nickel content (i.e., Fe-17Cr-12Ni and Fe-20Cr-25Ni) would not be possible by room temperature milling but was created by high strain rate cryogenic processing, the degree to which was compositional dependent. Post process annealing induced the reverse transformation from martensite-to-austenite the ratio of which was found to be a factor of alloy composition and annealing temperature. The real time in-situ x-ray studies showed that the martensite-to-austenite reverse transformation was completed at around 600 °C and 800 °C for Fe-18Cr-8Ni and Fe-20Cr-25Ni steels, respectively. Microscopy studies revealed a significant enhancement in the resistance to grain growth for Fe-17Cr-12Ni steel over other compositions at elevated temperatures as high as 1200 °C. As such, cryogenic processing following by reverse martensitic transformationmore » of high Ni containing alloys provides a pathway for developing higher heat resistant stainless steel alloys.« less

Authors:
 [1];  [2]
  1. Konya Necmettin Erbakan University, Department of Metallurgical & Materials Engineering, Konya 42090 (Turkey)
  2. U.S. Army Research Laboratory, Weapons and Materials Research Directorate, RDRL-WMM-F, Aberdeen Proving Ground, MD 21005-5069 (United States)
Publication Date:
OSTI Identifier:
22804945
Resource Type:
Journal Article
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 138; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-5803
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; AUSTENITE; CHROMIUM COMPOUNDS; CRYSTALS; DEFORMATION; GRAIN GROWTH; IRON COMPOUNDS; MARTENSITE; MICROSTRUCTURE; NANOSTRUCTURES; NICKEL COMPOUNDS; PHASE TRANSFORMATIONS; STAINLESS STEELS; TERNARY ALLOY SYSTEMS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats

Kotan, Hasan, and Darling, Kris A. A study of microstructural evolution of Fe-18Cr-8Ni, Fe-17Cr-12Ni, and Fe-20Cr-25Ni stainless steels after mechanical alloying and annealing. United States: N. p., 2018. Web. doi:10.1016/J.MATCHAR.2018.02.001.
Kotan, Hasan, & Darling, Kris A. A study of microstructural evolution of Fe-18Cr-8Ni, Fe-17Cr-12Ni, and Fe-20Cr-25Ni stainless steels after mechanical alloying and annealing. United States. doi:10.1016/J.MATCHAR.2018.02.001.
Kotan, Hasan, and Darling, Kris A. Sun . "A study of microstructural evolution of Fe-18Cr-8Ni, Fe-17Cr-12Ni, and Fe-20Cr-25Ni stainless steels after mechanical alloying and annealing". United States. doi:10.1016/J.MATCHAR.2018.02.001.
@article{osti_22804945,
title = {A study of microstructural evolution of Fe-18Cr-8Ni, Fe-17Cr-12Ni, and Fe-20Cr-25Ni stainless steels after mechanical alloying and annealing},
author = {Kotan, Hasan and Darling, Kris A.},
abstractNote = {In this study, high-energy mechanical alloying technique was used to produce nanocrystalline stainless steels of three different compositions from elemental powders. The microstructural evolution (grain growth and phase transformation) as a function of alloy compositions and annealing temperatures were investigated by room and high temperature x-ray diffraction experiments, transmission electron microscopy and focused ion beam microscopy. The results revealed that stainless steels with low nickel content (i.e., Fe-18Cr-8Ni) underwent a deformation-induced martensitic transformation during room temperature mechanical alloying. Deformation-induced martensitic transformation with increasing nickel content (i.e., Fe-17Cr-12Ni and Fe-20Cr-25Ni) would not be possible by room temperature milling but was created by high strain rate cryogenic processing, the degree to which was compositional dependent. Post process annealing induced the reverse transformation from martensite-to-austenite the ratio of which was found to be a factor of alloy composition and annealing temperature. The real time in-situ x-ray studies showed that the martensite-to-austenite reverse transformation was completed at around 600 °C and 800 °C for Fe-18Cr-8Ni and Fe-20Cr-25Ni steels, respectively. Microscopy studies revealed a significant enhancement in the resistance to grain growth for Fe-17Cr-12Ni steel over other compositions at elevated temperatures as high as 1200 °C. As such, cryogenic processing following by reverse martensitic transformation of high Ni containing alloys provides a pathway for developing higher heat resistant stainless steel alloys.},
doi = {10.1016/J.MATCHAR.2018.02.001},
journal = {Materials Characterization},
issn = {1044-5803},
number = ,
volume = 138,
place = {United States},
year = {2018},
month = {4}
}