1. To study the mechanical properties of NANOPERM and FINEMET alloys.
Mechanical Properties of Nanocomposite Alloys presented by Jennifer Barrow
Goals:
To study the mechanical properties of NANOPERM and FINEMET alloys.
To prepare the materials for experiments at the NHMFL.
Methods Used:
Melt spinning, Calorimetry, Nanoindentation

2. Rapid Solidification Processing Amorphous Tape Wound Core
Nanocrystallization & Calorimetry
Magnetic properties are well known for
FINEMET and NANOPERM
Mechanical properties are not.
A. Hsiao
CMU Ph.d Thesis

3. Background Composition: Nanocrystallization reaction (primary):
NANOPERM Fe88Zr7B4Cu1 FINEMET Fe73.53Si16.07B6.43Cu1.09Nb2.88
Nanocrystallization reaction (primary):
NANOPERM AmorphousαFe+amorphous’ (amorphous’ being rich in B, Zr)
FINEMET AmorphousFeSi +amorphous’ (amorphous’ being rich in Nb, B)
Nanocrystallization on heating
Material has interesting soft magnetic properties
~10 nm
Fe-Zr liquid is quenched to its amorphous phase. Alpha iron crystallizes

4. Strengthening mechanisms
(Fe,Fe3Si
or FeCo
based
glass)
Dense Random Packing of Hard Spheres (DRPHS): Amorphous Structure
Crystalline periodicity:(Fe,Fe3Si or FeCo)
Atom substitution puts strain on the crystal structure
Explain how dense random packing structure comes about.
Smaller atom substituted interstitially (B)
Larger atom substituted (Zr)

5. NANOPERM Hardness Data
Nanoindenter setup
19% vol
Unique hardness trend is due to strengthening mechanisms within the amorphous structure.
(interstitial or substitutional)
38% vol
0% vol
2% vol

6. Other observations in hardness data
Surface crystallization skews hardness data at beginning of Hardness vs. X curve (don’t have X = 0 at the surface)
Strengthening mechanisms (interstitial and substitutional) are cause for general increase in hardness.
Drop in hardness at large X is due to the fact that with increased crystallization, the material takes on mechanical properties of the softer nanocrystals

7. Future Work
Annealing samples to obtain X(t), or % composition vs. time and a complete TTT curve.
Polishing samples in order to eliminate surface crystallization.
Determining mechanical properties at large X

8. Acknowledgements Amy Hsiao’s Thesis Changyong Um Michael McHenry