TY - GEN
T1 - Microstructure formation of high pressure torsion processed (α + γ) two phase stainless steel
AU - Ota, Mie
AU - Nanya, Daiki
AU - Vajpai, Sanjay Kumar
AU - Ameyama, Kei
AU - Edalati, Kaveh
AU - Horita, Zenji
PY - 2017/1/1
Y1 - 2017/1/1
N2 - (α + γ) two phase stainless steel (Fe-21%Cr-4.8%Ni-1.5%Mo) powder was processed by high pressure torsion (HPT) and consolidation at room temperature. The received powder had fully α single phase due to the rapid cooling during gas atomizing process. Specimens after HPT process were heat treated at 1173K for 3.6ks. It was revealed that the decomposition of α phase to γ took place during the heat treatment. Detailed microstructure observation showed that an equiaxed (α + γ) micro-duplex structure was developed and its average grain size was approximately 3.2 micrometers. The same heat treatment given to the material without HPT resulted in a coarse two phase microstructure.Therefore, it is considered that an ultra fine grained microstructure was caused by increasing of nucleation sites for γ phase due to severe plastic deformation (SPD) of HPT process. Electron backscatter diffraction patterns (EBSD) analysis indicated that α phase has a {110}/ND strong texture, that is, the α phase seems to have single orientated coarse grain structure. The γ precipitates indicated a {111}/ND strong texture, and the crystallographic orientation relationship of Kurdjumov-Sachs was observed.
AB - (α + γ) two phase stainless steel (Fe-21%Cr-4.8%Ni-1.5%Mo) powder was processed by high pressure torsion (HPT) and consolidation at room temperature. The received powder had fully α single phase due to the rapid cooling during gas atomizing process. Specimens after HPT process were heat treated at 1173K for 3.6ks. It was revealed that the decomposition of α phase to γ took place during the heat treatment. Detailed microstructure observation showed that an equiaxed (α + γ) micro-duplex structure was developed and its average grain size was approximately 3.2 micrometers. The same heat treatment given to the material without HPT resulted in a coarse two phase microstructure.Therefore, it is considered that an ultra fine grained microstructure was caused by increasing of nucleation sites for γ phase due to severe plastic deformation (SPD) of HPT process. Electron backscatter diffraction patterns (EBSD) analysis indicated that α phase has a {110}/ND strong texture, that is, the α phase seems to have single orientated coarse grain structure. The γ precipitates indicated a {111}/ND strong texture, and the crystallographic orientation relationship of Kurdjumov-Sachs was observed.
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U2 - 10.4028/www.scientific.net/MSF.879.1365
DO - 10.4028/www.scientific.net/MSF.879.1365
M3 - Conference contribution
AN - SCOPUS:85000538688
SN - 9783035711295
T3 - Materials Science Forum
SP - 1365
EP - 1368
BT - THERMEC 2016
A2 - Sommitsch, Christof
A2 - Ionescu, Mihail
A2 - Mishra, Brajendra
A2 - Mishra, Brajendra
A2 - Kozeschnik, Ernst
A2 - Chandra, T.
PB - Trans Tech Publications Ltd
T2 - 9th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2016
Y2 - 29 May 2016 through 3 June 2016
ER -