1. Department of Mechanical Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801 e-mail:
2. Frederick Seitz Materials Research Laboratory, Department of Materials Science and Engineering and Department of Mechanical Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801 e-mail:
3. Fellow ASME Department of Mechanical Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801 e-mail: