Atom scale structure and minor solute exert strong effects on the corrosion properties of ideal solid

solution alloys

The effects of structural (order – disorder transformation, relaxation), chemical (solute clusters, minor solute elements) and structural+chemical defects (solute rich and lean nanocrystals in an amorphous solid solution) on corrosion are investigated using model alloys. • Disordered and ordered crystalline Fe50Pd50: The disordered structure has strong

grain orientation dependent dissolution over long times [1] which is morphologically different than after ordering [2]. The ordered surface initially shows crystallographic dissolution but at longer exposure durations only limited crystal dependence is apparent. This highlights a strong effects of neighbor atoms & bond length.

• Amorphous Cu75Hf20Dy05 [3] undergoes Hf selective dissolution in hydrofluoric acid and subsequent reorganization to form nanoporous fcc Cu much more quickly than its single phase crystalline solid solution counterpart. These results show that the ordered structure hinders surface diffusion of Cu compared to the amorphous variant, thereby slowing surface reorganization and inhibiting porosity formation.

Corrosion Mechanisms in Amorphous Solid Solution Alloys: Role(s) of Minor Alloying Elements

John R. Scully, University of Virginia Main Campus, DMR 0906663

[1] disordered fcc Fe50Pd50

400 s

{100} {111}

[2] ordered pT Fe50Pd50

400 s

2500 s

400 s

Key result: Dissolution linearly dependent on plane normal angle from {100} and {111}

Key Result: Hf diss. occurs more readily from amorphous structure. Ordered structure inhibits surface

diffusion of Cu.

[3] Amorphous vs. Crystalline Cu75Hf20Dy05

1

2

3

5 4

disordered

ordered

Compositional orderingSlight lattice expansion

Amorphous CrystallineCu Cu

Cu75Hf20Dy05

6

6

42

1

3

5

Corrosion Education• 3 high school students (M. Fox, S. Gorsch, L. Scully), 3 Undergraduates

(H. Bindig, W. McCarthy, A. Nguyen), 3 graduate students (T. Aburada, N. Tailleart, D. Horton), and 1 post-doctoral researchers (H. Ha) contributed to this NSF-supported project.

• Graduate & undergraduate courses in corrosion taught both in class and via distance learning (both MSE 7080 and MSE 3080) for Made-in-Virginia for Engineers that bring engineering education to workers.

• John R. Scully served on National Academy Study on Research

Opportunities In Corrosion (ROCSE). (Fall 2010). Corrosion Video distributed

(Title) IIName, Institution, DMR Award#

Spatio-temporal Chaos in Systems of Broken Symmetry

Eberhard Bodenschatz, Cornell University, DMR Award#0072077

Outreach • NanoDays participation with nano-scale corrosion applications at local schools and museums • cKITs (a set of corrosion experiments) purchased from National Association of Corrosion Engineers supplied to local K-12

schools• Materials science and engineering demonstrations and lab tours are given in UVa MSE to foster an interest in the physical

sciences and materials science.

CORROSION MECHANISMS IN AMORPHOUS ALLOYS: CRITICAL COMPOSITIONAL AND STRUCTURAL DEFECTS FOR LOCAL CORROSION

John R. Scully, University of Virginia Main Campus, DMR 0906663

Awards and Honors• Nicole Tailleart, John R. Scully: Inaugural Award Recipients of the Corrosion Journal Best Paper Award, "User-selectable Barrier,

Sacrificial Anode, and Active Corrosion Inhibiting Properties of Al-Co-Ce Alloys for Coating Applications." NACE Inter. Conference, 2010.• UVA's Center for Electrochemical Science and Engineering received the 2009 NACE Distinguished Organization Award• John R. Scully: received the H.H. Uhlig Award, 2009 of the Electrochemical Society for excellence in corrosion research.• Tomohiro Aburada was one of twelve invited students internationally to present at Gordon Research Seminar, New London, NH 2010.• H. Bindig Runner-up in the 2011 Individual Undergraduate Research and Design Symposium selected from 1300 graduating UVA

engineers

H. Bindig, Runner-up – 2011 Individual Undergraduate

Research and Design Symposium