Solute partitioning in partially crystallized Al-Ni-Ce(-Cu) metallic glasses
- Tohoku Univ., Sendai (Japan). Inst. for Materials Research
A new family of aluminum based metallic glasses show remarkably high tensile strength as well as good ductility. These metallic glasses are based on Al-TM-RE (TM = transition metals, RE = rare earths), containing 80--92 at.% Al. It has been reported that the tensile yield strength of these materials reaches as high as 800 MPa in the amorphous state, and can be increased to 1,500 MPa by partial crystallization. The partially crystallized metallic glass consists of nanoscale fcc particles embedded in an amorphous matrix. The particle dispersion can be controlled by varying the cooling rate, and the yield strength reaches a maximum with a particle volume fraction of approximately 20%. The average grain size can be controlled by substituting Cu and Ag for the transition element. Isochronal differential scanning calorimetry (DSC) has shown that crystallization from the fully amorphous state to the fully crystallized state proceeds in two stages. Lattice parameter measurements suggest that the nanocrystalline fcc particles are the [alpha]-Al phase, but this remains unconfirmed by other techniques. It has also been reported that the crystallization kinetics are very fast and only the growth stage is observed in isothermal DSC. This suggests that certain heterogeneities that may act as nucleation sites for crystallization may be present in the melt-spun alloys. Furthermore, it is not understood why nanocrystalline particles are formed by the primary crystallization process, whereas most crystallization from metallic glasses lead to gross dendritic particles. The goal of this study was to examine the solute partitioning during the primary crystallization process form the initial metallic glass state to the partially crystallized state and to understand the mechanism of the nanocrystalline particle formation. In the present paper, the authors report only atom probe analysis results of partially crystallized Al-10Ni-3Ce and Al-7Ni-3Ce-3Cu alloys.
- OSTI ID:
- 6824144
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Vol. 32:2; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM BASE ALLOYS
MICROSTRUCTURE
CERIUM ALLOYS
COPPER ALLOYS
METALLIC GLASSES
NICKEL ALLOYS
CRYSTALLIZATION
EXPERIMENTAL DATA
MECHANICAL PROPERTIES
PHASE STUDIES
SEGREGATION
ALLOYS
ALUMINIUM ALLOYS
DATA
INFORMATION
NUMERICAL DATA
PHASE TRANSFORMATIONS
RARE EARTH ALLOYS
360102* - Metals & Alloys- Structure & Phase Studies