Synthesis Feasibility Brief for Fe17W3

Proposed Fabrication Routes

Route 1: Arc Melting + Annealing (Literature-Supported)

Target composition: Fe-15 at.% W Process:

1. Arc melt Fe and W in Ar atmosphere

2. Cast into water-cooled copper mold

3. Anneal at 1000°C for 24h in vacuum

Phase-control variables:

• Cooling rate: <10 K/min to avoid amorphous phase

• Annealing temperature: 950-1050°C

• W concentration: 14-16 at.%

Likely competing phases:

• α-Fe (bcc) - dominant at low W

• FeW (L1₀) - ordered compound

• Fe₃W - high-temperature phase

XRD signatures:

• (200) peak at ~44.5° 2θ (Cu Kα)

• (111) peak at ~50.2° 2θ

• (220) peak at ~64.8° 2θ

Assessment: Literature-supported - similar Fe-W alloys have been successfully synthesized using this method.

Route 2: Mechanical Alloying (Speculative)

Target composition: Fe-15 at.% W Process:

1. Ball mill Fe and W powders in Ar

2. Mill for 20-40h at 300 rpm

3. Consolidate by hot pressing at 900°C

Phase-control variables:

• Ball-to-powder ratio: 10:1

• Milling time: 20-40h

• Consolidation pressure: 100 MPa

Likely competing phases:

• Amorphous phase (if milling too long)

• α-Fe (bcc)

• FeW (L1₀)

XRD signatures:

• Broad amorphous halo (20-60° 2θ) if over-milled

• Sharp (200) peak at ~44.5° 2θ if crystalline

Assessment: Speculative - mechanical alloying of Fe-W has not been reported for this composition; risk of amorphization is high.

Recommendation

Route 1 (Arc Melting) is the preferred approach due to:

1. Proven method for Fe-W alloys

2. Better phase control

3. Higher reproducibility

4. Lower risk of amorphization

Risk Assessment

• High risk: W segregation during solidification

• Medium risk: Formation of competing phases

• Low risk: Structural instability

Next Steps

1. Synthesize Fe-15 at.% W via arc melting

2. Characterize by XRD and SEM-EDS

3. Measure magnetic properties (VSM, SQUID)

4. Compare with predicted structure