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Characterisation of microalloy precipitates in the austenitic range of high strength low alloy steels
Author(s) -
Cancio María José,
Echaniz Guillermo,
Pérez Teresa Estela
Publication year - 2002
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.200200219
Subject(s) - carbide , metallurgy , tin , alloy , dissolution , materials science , nitride , transmission electron microscopy , chemistry , crystallography , composite material , nanotechnology , layer (electronics)
Transmission electron microscopy was used to investigate the particle size distribution, morphology, composition, and crystallography of microalloy (Ti, Nb) precipitates in 4130 steels between 900 to 1250 °C. Considering the Ti fraction, the size and the morphology, two types of precipitates were identified: cuboidal coarse TiNbMo carbonitrides, rich in TiN and a fine dispersion between 2 to 25 nm of TiNbMo carbides. The progressive formation of higher soluble phases, such as NbC and MoC, was observed on the pre‐existent, TiN and TiC precipitates. In the studied conditions, nitrides were found to be insoluble and quite resistant to coarsening. On the contrary, carbides not only began dissolution in the range of 960 ‐ 1000 °C according to the microalloy content in the steel, but also produced abnormal grain growth.