[1] Univ Munster, Inst Mat Phys, Wilhelm Klemm Str 10, D-48149 Munster, Germany
[2] Univ Bayreuth, Met & Alloys, Prof Rudiger Bormann Str 1, D-95447 Bayreuth, Germany
[3] Worcester Polytech Inst, Dept Mech Engn, 100 Inst Rd, Worcester, MA 01609 USA
[4] Univ Stuttgart, Inst Mat Sci, Pfaffenwaldring 55, D-70569 Stuttgart, Germany