ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The phase transformations and the microstructure developments in Fe-Cu base alloysduring isothermal aging are simulated based on the phase-field method. Since the chemical freeenergy used in this simulation is obtained from the thermodynamic database of phase diagrams,the calculated microstructure changes are directly related to the phase diagram of the real alloysystem. Firstly the phase decomposition and the microstructure changes in the Fe-Cu binary alloysystem are demonstrated as the simple example of the phase-field modeling, i.e., the phasedecomposition in bcc phase where the Cu-rich phase forms, the structural phase transformationfrom bcc to fcc phase in the Cu-rich nano-particle, and the shape change of fcc-Cu precipitatesfrom sphere to rod. Secondly, the phase decomposition in bcc phase of the multi-component alloyssuch as the Fe-Cu-X (X=Mn,Ni) ternary system and the Fe-Cu-Mn-Ni quaternary alloy issimulated. At the early stage of aging, the Cu-rich zone with bcc structure begins to nucleate, andthe component X (=Mn, Ni) is partitioned to the Cu-rich phase. When the Cu composition in theprecipitate reaches equilibrium, the component X inside the precipitates moves toward to theinterface region between the precipitate and matrix. Finally, there appears the shell structure thatthe Cu precipitates surrounded by the thin layer with high concentration of component X
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.2383.pdf
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