Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation

The cracking initiation mechanism of high Cu-bearing nitrogen-alloyed austenitic stainless steel was systematically investigated by using a Gleeble-1500D simulator under different strains and deformation temperatures in the hot deformation process. The cracking initiation process and microstructure...

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Main Authors: Xiao-Yang Fu, Pu-Cun Bai, Ji-Chun Yang
Format: Article
Language:English
Published: MDPI AG 2018-10-01
Series:Metals
Subjects:
Online Access:http://www.mdpi.com/2075-4701/8/10/816
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spelling doaj-82454729d0894a27997045346fbf3d692020-11-25T01:27:06ZengMDPI AGMetals2075-47012018-10-0181081610.3390/met8100816met8100816Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot DeformationXiao-Yang Fu0Pu-Cun Bai1Ji-Chun Yang2School of Material Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaSchool of Material Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaSchool of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, ChinaThe cracking initiation mechanism of high Cu-bearing nitrogen-alloyed austenitic stainless steel was systematically investigated by using a Gleeble-1500D simulator under different strains and deformation temperatures in the hot deformation process. The cracking initiation process and microstructure variations were characterized by optical microscopy (OM), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). In the deformation process, Cu-rich and Cr-rich phases were found around the microscopic crack at the strain of 0.5. Cu content was found to be higher at the grain boundary than inside the grain. The equilibrium phase diagram calculated by Thermo-calc shows that Cu precipitates out in the form of an elementary substance below 1022 °C, when the Cu mass fraction reaches 5%. Meanwhile, dislocation walls and twin crystals were observed by TEM. The results show that the synergistic effect of the secondary phases, such as M23C6 precipitated along the grain boundary and stress concentration, lead to crack generation, which is lower at high temperature and low temperature and is higher at 1100 °C and increase as the strain increases.http://www.mdpi.com/2075-4701/8/10/816Cu-bearingnitrogen-alloyedaustenitic stainless steelcrackhot deformation
collection DOAJ
language English
format Article
sources DOAJ
author Xiao-Yang Fu
Pu-Cun Bai
Ji-Chun Yang
spellingShingle Xiao-Yang Fu
Pu-Cun Bai
Ji-Chun Yang
Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation
Metals
Cu-bearing
nitrogen-alloyed
austenitic stainless steel
crack
hot deformation
author_facet Xiao-Yang Fu
Pu-Cun Bai
Ji-Chun Yang
author_sort Xiao-Yang Fu
title Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation
title_short Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation
title_full Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation
title_fullStr Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation
title_full_unstemmed Cracking the Initiation Mechanism of High Cu-Bearing Nitrogen-Alloyed Austenitic Stainless Steel in the Process of Hot Deformation
title_sort cracking the initiation mechanism of high cu-bearing nitrogen-alloyed austenitic stainless steel in the process of hot deformation
publisher MDPI AG
series Metals
issn 2075-4701
publishDate 2018-10-01
description The cracking initiation mechanism of high Cu-bearing nitrogen-alloyed austenitic stainless steel was systematically investigated by using a Gleeble-1500D simulator under different strains and deformation temperatures in the hot deformation process. The cracking initiation process and microstructure variations were characterized by optical microscopy (OM), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). In the deformation process, Cu-rich and Cr-rich phases were found around the microscopic crack at the strain of 0.5. Cu content was found to be higher at the grain boundary than inside the grain. The equilibrium phase diagram calculated by Thermo-calc shows that Cu precipitates out in the form of an elementary substance below 1022 °C, when the Cu mass fraction reaches 5%. Meanwhile, dislocation walls and twin crystals were observed by TEM. The results show that the synergistic effect of the secondary phases, such as M23C6 precipitated along the grain boundary and stress concentration, lead to crack generation, which is lower at high temperature and low temperature and is higher at 1100 °C and increase as the strain increases.
topic Cu-bearing
nitrogen-alloyed
austenitic stainless steel
crack
hot deformation
url http://www.mdpi.com/2075-4701/8/10/816
work_keys_str_mv AT xiaoyangfu crackingtheinitiationmechanismofhighcubearingnitrogenalloyedausteniticstainlesssteelintheprocessofhotdeformation
AT pucunbai crackingtheinitiationmechanismofhighcubearingnitrogenalloyedausteniticstainlesssteelintheprocessofhotdeformation
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