How are new orientations generated during primary recrystallization?
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How are New Orientations Generated during Primary Recrystallization?
PETER HAASEN
High-voltage electron microscopy (HVEM) o f in situ recrystallizing single crystals and growth competition experiments, according to Beck,t~3] have been performed in o r d e r to better understand how new orientations develop during primary recrystallization. The specimens used were single crystals o f AI, C u , Cu with Mn, o r P additions in o r d e r to vary stacking fault energy and size misfit o f the solute. Evidently, nucleation is always in orientations o f the deformed matrix. New orientations develop by annealing twinning, unless the deformation microstructure (DM) o f 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 ~-~.
Dr. Haasen was born and educated in Gotha, Germany. His education was interrupted b y 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 G6ttingen, completing his P h . D . under Richard Becker and G_ Leibfried. He served as a Postdoctoral F e l l o w (1954-56) at the Institute for the S t u d y ofMetals of the University of Chicago, working with C.S. Ban-ett, L. Meyer, and A.W. Lawson. He was then a Scientific A s s o c i a t e at the MaxPlanck-Institut for Metals Research in Stuttgart (1956-58). Dr. Haasen has been C h a i r of Metal Physics at the University of G6ttingen since 1959 and Director of the Institut for Metallphysik. W o r k o n plastic deformation, defects in solids, p h a s e 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 A
textbook o n this subject with R.W. C a h n , as well as a series o n "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 G~Sttingen i n Germany, the European Academy in L o n d o n , and the United States National Academy of Engineering in Washington, D C . He received the Heyn Medal of the Deutsche Gesellschaft ffir Metallkunde, the M6dail Le Chatelier of the Soci6te Fran~aise de Metallurgie, the R.F. Mehl Medal of AIME, and the H u m b o l d t Prize of the French Government. The Edward D e M i l l e C a m p b e l l Memorial Lecture was established i n 1926 as an annual lecture in memory of and in recognition of the outstanding scientific contributions t o the metallurgical profession b y a distinguished educator who was b l i n d for all but t w o years of his professional life. It recognizes demonstrated ability in metallurgical science and engineering. VOLUME 24A, MAY 1993--1001
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INTRODUCTION
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