TEM studies of melt‐spun alloys with liquid miscibility gap

Abstract

Summary The microstructures of the Fe–Cu‐based alloys melt‐spun from various temperatures are presented. Two compositions, with different Fe and Cu content, revealing liquid miscibility gap, were studied. Nonuniform, large‐elongated areas were observed for lower melt‐spinning temperatures, indicating liquid/liquid phase separation in the crucible before cooling. An increase of the melt ejection temperature, followed by rapid cooling, brought about precipitation process within homogeneous melt. Studies of the system with higher Fe content proved amorphous nature of the matrix and crystalline structure of the primary formed Cu‐rich precipitates. Moreover, generations of the secondary spherical particles, precipitated within the previously formed Cu‐rich melt, were observed. The microstructure of the melt‐spun alloy with a higher Cu content, on the other hand, consisted of the Fe‐rich amorphous spherical particles formed during cooling of the Cu‐rich liquid. The precipitation of the secondary Cu‐rich particles in the primary formed Fe‐rich was also observed.

Microstructure and properties of the in situ formed amorphous-crystalline composites in the Fe–Cu-based immiscible alloys

“…If GFA of one of the melt will be not sufficient, the amorphous-crystalline composite microstructure can be obtained during cooling [16][17][18][19]. This paper shows the microstructures and mechanical properties of the melt-spun Fe 30 Cu 32 Si 13 B 9 Al 8 Ni 6 Y 2 and Fe 44 Cu 18 Si 13 B 9 Al 8 Ni 6 Y 2 alloys.…”

AMORHIZATION AND LIQUID STATE SEPARATION IN Ni80-2xCuxFexP20 ALLOYS

“…Low content of Ni in the alloy does not assure formation of the uniform liquid that can be stable enough to form metallic glass below the glass transition temperature, because both liquids Fe-rich and Cu-rich are below their T 0 temperatures [26]. It is worth to note that there are Fe-based alloys where in spite of a substantial concentration of Cu the vitrification of the matrix was obtained [27][28][29][30][31][32][33][34].…”

Formation of amorphous phase with crystalline globules in Fe–Cu–Nb–B immiscible alloys

“…The formation of two amorphous phases originates from a positive heat of mixing (DH mix ) between the two major elements and a high glass-forming ability (GFA) of the separated liquids. In the case of Fe-Cu-based alloys, the formation of a two-phase metallic amorphous material has not yet been reported; whereas the simultaneous occurrence of liquid phase separation and Fe-based amorphous phase formation has been well studied [25][26][27][28][29][30][31][32][33][34][35][36]. Spherical crystalline precipitates tend to form in the Fe-rich, Fe-Cu-based multicomponent immiscible alloys with amorphous phase formation, indicating that their liquid phase separation results in the formation of composites with a spherical crystalline phase and an Fe-based amorphous matrix.…”