TY - JOUR
T1 - Simulation of the pre-precipitate in Ni75Al5Cr20 alloy by microscopic phase-field method
AU - Tang, Hongkui
AU - Wang, Yongxin
AU - Chen, Zheng
AU - Dong, Weiping
AU - Liu, Xiaofeng
AU - Wang, Yongbiao
PY - 2010/9
Y1 - 2010/9
N2 - DO22 phase with long period ordered structure is the main strengthening phase in Ni-Al-Cr alloy applied in high temperatures, as it hinders the slipping of dislocations during the deformation. Structure transformation from fcc to DO22 during the ordering process and phase separation have been studied extensively, but there are only a few of reports on the phase transformation in early precipitation stage, especially on the phase transformation of metastable pre-precipitate. In this paper, the microscopic phase-field method was employed to study the pre-precipitate during the transformation from fcc to DO22 in Ni75Al5Cr20 alloy. The early ordering process of Ni75Al5Cr20 alloy are simulated at four different temperatures, and the relationship between the order parameter evolutions of Cr and Al atoms on (001) and (002) planes of disordered fcc solid solution and structure evolution will be investigated. The simulation results demonstrate that the parent phase transformed into L10(M=1) pre-precipitate with long period ordered structure before DO22 phase formed. At the early aging stage, the atomic ordering is proceeded on each plane as the atoms migrate on planes only, and the L10(M=1) pre-precipitate formed in the way of congruent ordering. Then, the further ordering of atoms on (001) plane was induced by the migration of atoms between different planes, and the pre-precipitate with L10(M=1) structure is gradually transformed into DO22 phase. The incubation period and existent time of L10(M=1) phase are prolonged with the temperature increasing, as a result, the incubation period of DO22 phase is longer when the aging temperature is higher, and the formation of L10(M=1) pre-precipitate is easier when the temperature is lower.
AB - DO22 phase with long period ordered structure is the main strengthening phase in Ni-Al-Cr alloy applied in high temperatures, as it hinders the slipping of dislocations during the deformation. Structure transformation from fcc to DO22 during the ordering process and phase separation have been studied extensively, but there are only a few of reports on the phase transformation in early precipitation stage, especially on the phase transformation of metastable pre-precipitate. In this paper, the microscopic phase-field method was employed to study the pre-precipitate during the transformation from fcc to DO22 in Ni75Al5Cr20 alloy. The early ordering process of Ni75Al5Cr20 alloy are simulated at four different temperatures, and the relationship between the order parameter evolutions of Cr and Al atoms on (001) and (002) planes of disordered fcc solid solution and structure evolution will be investigated. The simulation results demonstrate that the parent phase transformed into L10(M=1) pre-precipitate with long period ordered structure before DO22 phase formed. At the early aging stage, the atomic ordering is proceeded on each plane as the atoms migrate on planes only, and the L10(M=1) pre-precipitate formed in the way of congruent ordering. Then, the further ordering of atoms on (001) plane was induced by the migration of atoms between different planes, and the pre-precipitate with L10(M=1) structure is gradually transformed into DO22 phase. The incubation period and existent time of L10(M=1) phase are prolonged with the temperature increasing, as a result, the incubation period of DO22 phase is longer when the aging temperature is higher, and the formation of L10(M=1) pre-precipitate is easier when the temperature is lower.
KW - L1(M=1) structure
KW - Long period ordered structure
KW - Microscopic phase-field method
KW - Ni-Al-Cr alloy
KW - Pre-precipitate
UR - http://www.scopus.com/inward/record.url?scp=77958464784&partnerID=8YFLogxK
U2 - 10.3724/SP.J.1037.2010.00186
DO - 10.3724/SP.J.1037.2010.00186
M3 - 文章
AN - SCOPUS:77958464784
SN - 0412-1961
VL - 46
SP - 1147
EP - 1152
JO - Jinshu Xuebao/Acta Metallurgica Sinica
JF - Jinshu Xuebao/Acta Metallurgica Sinica
IS - 9
ER -