Strain induced decomposition and precipitation of carbides in a molybdenum–hafnium–carbon alloy
Strain induced decomposition and precipitation of carbides in a molybdenum–hafnium–carbon alloy
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DOI：
10.1016/j.jallcom.2013.06.086
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发表时间：
2013-12
影响因子：
6.2
通讯作者：
Christopher Pöhl;D. Lang;J. Schatte;H. Leitner
中科院分区：
文献类型：
--
作者：
Christopher Pöhl;D. Lang;J. Schatte;H. Leitner
In the present study of a sintered and thermo-mechanically processed Mo–Hf–C (MHC) alloy the strain induced decomposition of Mo–carbides and subsequent precipitation of Hf-carbides was revealed. The microstructural characterization was performed with atom probe tomography (APT), transmission electron microscopy (TEM), X-ray diffraction (XRD) and optical light microscopy (OLM). During annealing of deformed conditions it can be shown by TEM analysis that Hf-carbides were preferentially formed on dislocations and occasionally on (sub)grain boundaries. XRD and OLM investigations revealed that the required C for the Hf-carbides was delivered by the decomposition of Mo–carbides which are originally located at former grain boundaries in the as-sintered condition. It has been shown that for this decomposition mechanical strain prior to annealing was required. In the early stages of precipitation APT analyses revealed a significant segregation of C and Hf atoms to dislocations and boundaries. Finally, the authors deduced that due to the dislocation–precipitation interaction the misfit strain was effectively reduced and therefore, the Hf-carbides are located on dislocations and (sub)grain boundaries.
