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The e a r l y stage of i s o t h e r m a l r e c r y s t a l l i z a t i o n of m o d e r a t e l y d e f o r m e d , p o l y c r y s t a l l i n e a l l o y s of z o n e - r e f i n e d a l u m i n u m c o n t a i n i n g 20 and 45 at. ppm of Au has b e e n studied by q u a n t i t a t i v e m e t a l l o g r a p h y . The b a s i c s t r u c t u r a l p a r a m e t e r s Xv, the volume f r a c t i o n r e c r y s t a l l i z e d , and Sv, the g r a i n b o u n d a r y a r e a p e r unit v o l u m e , were m e a s u r e d on s p e c i m e n s a n n e a l e d for different t i m e s at specific t e m p e r a t u r e s in the range 80 ~ to 187~ Both the m a x i m u m , Gin, and the a v e r a g e , G, growth r a t e s of the r e c r y s t a l l i z i n g g r a i n s were a l s o d e t e r m i n e d . All r e s u l t s could be i n t e r p r e t e d in t e r m s of a s i t e - s a t u r a t e d , m a t r i x g r a i n edge n u c l e a t i o n at z e r o t i m e with s u b s e q u e n t t w o - d i m e n s i o n a l growth p e r p e n d i c u l a r to the n u c l e a t e d edge c o n t r o l l i n g r e c r y s t a l l i z a t i o n k i n e t i c s . An equation r e l a t i n g Sv to Xv was d e r i v e d and found to d e s c r i b e the e x p e r i m e n t a l data quite well. E x p e r i m e n t a l l y , the r a t i o Gm/G was 2.6 and the a c t i v a t i o n e n e r g y for growth was 25,700 cal p e r m o l e .

P R I M A R Y r e c r y s t a l l i z a t i o n is the p r o c e s s whereby c o m p a r a t i v e l y s t r a i n free g r a i n s nucleate and grow into a d e f o r m e d m a t r i x until the l a t t e r is c o n s u m e d . Often the p r o c e s s can be followed u n a m b i g u o u s l y only by v i s u a l i n s p e c t i o n of the m i c r o s t r u c t u r e . The p r e s e n t paper i s c o n c e r n e d with the i s o t h e r m a l r e c r y s t a l l i z a tion of m o d e r a t e l y d e f o r m e d , p o l y c r y s t a l l i n e alloys of z o n e - r e f i n e d a l u m i n u m c o n t a i n i n g 20 a n d 45 at. ppm of Au* as studied by m e a n s of q u a n t i t a t i v e m e t a l l o g r a p h y . *Thesealloysare two of a seriesof AI-Aualloysthat werestudiedin an effort to evaluatequantitativelythe influenceof trace amountsof impuritieson recrystallization. U s i n g s y s t e m a t i c point counting p r o c e d u r e s , the b a s i c s t r u c t u r a l p a r a m e t e r s Xv, the v o l u m e f r a c t i o n r e c r y s t a l l i z e d , and Sv, the g r a i n b o u n d a r y a r e a per unit volume s e p a r a t i n g r e c r y s t a l l i z e d r e g i o n s from u n r e c r y s t a l l i z e d ones, were m e a s u r e d on c o l d - r o l l e d s p e c i m e n s a n n e a l e d for v a r i o u s t i m e s at specific t e m p e r a t u r e s in the range 80 ~ to 187~ Both the m a x i m u m , Gin, and the a v e r a g e , G, growth r a t e s of the r e c r y s t a l l i z i n g g r a i n s were also d e t e r m i n e d . Attention was focused on the i n t e r r e l a t i o n s h i p b e t w