[1] Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA
[2] Penn State Univ, Mat Res Inst, University Pk, PA 16802 USA
[3] Univ Sheffield, Dept Mat Sci & Engn, Sheffield S1 3JD, S Yorkshire, England
[4] Oak Ridge Natl Lab, Ctr Nanophase Mat Sci, Oak Ridge, TN 37831 USA