TY - JOUR
T1 - Coarsening of nanoscale (Ti,Mo)C precipitates in different ferritic matrixes
AU - Cheng, Lei
AU - Cai, Qingwu
AU - Yu, Wei
AU - Lv, Jinlong
AU - Miura, Hideo
N1 - Funding Information:
This work was supported by the National Natural Science Foundation of China (No. 51274036 ).
PY - 2018/8
Y1 - 2018/8
N2 - Coarsening of nanoscale (Ti,Mo)C precipitates within quasi-polygonal ferritic (QPF) matrix and polygonal ferritic (PF) matrix is studied via HRTEM and In-situ heating TEM. Influenced by different nucleation processes, inverse coarsening process showing dissolution of large clustered precipitates and growth of small interphase precipitates is directly observed in the PF matrix. However, due to the evolution of high-density subboundaries, coarsening of precipitates in QPF matrix is mainly characterized by the subboundary migration assisted coarsening process, during which arch-like coarsened precipitates form after the sweeping of subboundaries. Analysis of atomic structure clarify that “imposts” of the arch-like coarsened precipitates are established by the re-precipitation of solute atoms from movable subboundary to the close packed planes {111} of (Ti,Mo)C precipitates, and that the “key stones” are constructed due to the change of re-precipitation planes to {200}. Geometric phase analysis (GPA) illustrates that not only the change of re-precipitation direction during the formation of arch-like precipitates, but also the selective coarsening of clustered precipitates in PF matrix, is caused by the highly anisotropic strain field around (Ti,Mo)C precipitates.
AB - Coarsening of nanoscale (Ti,Mo)C precipitates within quasi-polygonal ferritic (QPF) matrix and polygonal ferritic (PF) matrix is studied via HRTEM and In-situ heating TEM. Influenced by different nucleation processes, inverse coarsening process showing dissolution of large clustered precipitates and growth of small interphase precipitates is directly observed in the PF matrix. However, due to the evolution of high-density subboundaries, coarsening of precipitates in QPF matrix is mainly characterized by the subboundary migration assisted coarsening process, during which arch-like coarsened precipitates form after the sweeping of subboundaries. Analysis of atomic structure clarify that “imposts” of the arch-like coarsened precipitates are established by the re-precipitation of solute atoms from movable subboundary to the close packed planes {111} of (Ti,Mo)C precipitates, and that the “key stones” are constructed due to the change of re-precipitation planes to {200}. Geometric phase analysis (GPA) illustrates that not only the change of re-precipitation direction during the formation of arch-like precipitates, but also the selective coarsening of clustered precipitates in PF matrix, is caused by the highly anisotropic strain field around (Ti,Mo)C precipitates.
KW - Coarsening
KW - HRTEM
KW - In-situ heating
KW - Precipitation
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U2 - 10.1016/j.matchar.2018.05.034
DO - 10.1016/j.matchar.2018.05.034
M3 - Article
AN - SCOPUS:85048483670
VL - 142
SP - 195
EP - 202
JO - Materials Characterization
JF - Materials Characterization
SN - 1044-5803
ER -