O. Drbohlav et Ar. Yavari, MECHANICAL ALLOYING AND THERMAL-DECOMPOSITION OF FERROMAGNETIC NANOCRYSTALLINE FCC-CU50FE50, Acta metallurgica et materialia, 43(5), 1995, pp. 1799-1809
Citations number
23
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
The mechanical alloying of usually immiscible Fe and Cu is monitored b
y magnetic and structural measurements. The Fe component of a mixture
of global composition Fe50Cu50 is found to dissolve into the Cu-f.c.c.
matrix after nanofragmentation following a previously developed therm
odynamic model. The resulting nanocrystalline f.c.c. FeCu supersaturat
ed solid solution with a Curie temperature of about 480 K is found to
phase-separate above 500 K through a spinodal decomposition mechanism
that occurs independently in each nanograin with little grain growth.
The evolution of magnetization and of the diffraction patterns during
decomposition indicate that more than 50% of the emerging Fe-rich zone
s remain f.c.c. after the exothemic heat release corresponding to chem
ical phase-separation. The decomposition of supersaturated f.c.c. FeCu
thus generates Fe-rich f.c.c. zones that have not been obtained by me
chanical alloying or vapor-deposition techniques and provides interest
ing information on the magnetic properties of gamma-Fe(Cu) which is fo
und to be ferromagnetic as compared to pure gamma-Fe which is antiferr
omagnetic.