How are new orientations generated during primary recrystallization?
- PDF / 4,314,188 Bytes
- 15 Pages / 603.28 x 783.28 pts Page_size
- 90 Downloads / 168 Views
How are New Orientations Generated during Primary Recrystallization?
PETER HAASEN
High-voltage electron microscopy (HVEM) of in situ recrystallizing single crystals and growth competition experiments, according to Beck, lj3J have been performed in order to better understand how new orientations develop during primary recrystallization. The specimens used were single crystals of A1, Cu, Cu with Mn, or P additions in order to vary stacking fault energy and size misfit of the solute. Evidently, nucleation is always in orientations of the deformed matrix. New orientations develop by annealing twinning, unless the deformation microstructure (DM) of a rolled polycrystal is already inhomogeneous enough. In both cases, the same fastgrowing grain boundaries (GBs) determine the final recrystallization texture. These GBs differ depending on purity and solute and can be characterized (and compared with respect to calculated structures) by the nearest coincidence site density E-~.
Dr. Haasen was born and educated in Gotha, Germany. His education was interrupted by a short term of military service and prisonership of war. After apprenticeship as a mechanic, he studied physics and metallurgy (1946-53) at the University of Grttingen, completing his Ph.D. under Richard Becker and G. Leibfried. He served as a Postdoctoral Fellow (1954-56) at the Institute for the Study of Metals o f the University o f Chicago, working with C.S. Barrett, L. Meyer, and A . W . Lawson. He was then a Scientific Associate at the MaxPlanck-Institut for Metals Research in Stuttgart (1956-58). Dr. Haasen has been Chair of Metal Physics at the University of Grttingen since 1959 and Director of the Institut for Metallphysik. Work on plastic deformation, defects in solids, phase transformations, analytical field ion microscopy, high-resolution transmission electron microscopy, hardening of magnets and superconductors, and recrystallization. He has written the textbook, Physical Metallurgy, and edited another METALLURGICAL TRANSACTIONS B
textbook on this subject with R.W. Cahn, as well as a series on "Materials Science and T e c h n o l o g y " with Cahn and E.R. Kramer. Haasen is a member of the Academies Leopoldina and Gtittingen in Germany, the European Academy in London, and the United States National Academy of Engineering in Washington, DC. He received the Heyn Medal of the Deutsche Gesellschaft for Metallkunde, the Mrdail Le Chatelier of the Soci6te Fran~aise de Metallurgie, the R.F. Mehl Medal of AIME, and the Humboldt Prize of the French Government. The Edward DeMille Campbell Memorial Lecture was established in 1926 as an annual lecture in memory of and in recognition of the outstanding scientific contributions to the metallurgical profession by a distinguished educator who was blind for all but two years of his professional life. It recognizes demonstrated ability in metallurgical science and engineering. VOLUME 24B, APRIL 1993--225
I.
INTRODUCTION
W H E N I was a postdoctoral fellow at the Institute for the Study of Metals at the University
Data Loading...
