Monotectic composite growth
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ing p h a s e s would be i n c o r p o r a t e d . T h e t h i c k n e s s of the f i l m of the i n t r u d i n g w e t t i n g liquid i s a function of a p r e s s u r e c a l l e d the d i s j o i n i n g p r e s s u r e . 7 It r e p r e e u t e c t i e a l l o y s the p h a s e s that f o r m s i m u l t a n e o u s l y s e n t s w o r k done in m o v i n g the two n o n c o n t a c t i n g f r o m the m e l t a r e both solid; for m o n o t e c t i c a l l o y s p h a s e s c l o s e r t o g e t h e r and in the l i m i t of z e r o inone p h a s e is a liquid (L2) which s o l i d i f i e s l a t e r at t r u d i n g f i l m t h i c k n e s s it r e p r e s e n t s the w o r k done in s o m e l o w e r t e m p e r a t u r e and which is i m m i s c i b l e with c r e a t i n g the s u r f a c e of d i r e c t c o n t a c t with i t s h i g h e r the o r i g i n a l m e l t (Lx). T h e i n i t i a l c o m p o s i t e that i s f r e e e n e r g y . The h y d r o d y n a m i c f o r c e s of liquid flowgrown by a m o n o t e c t i c r e a c t i o n is t h e r e f o r e a s o l i d ing a r o u n d the nonwetting p h a s e to the g r o w i n g c r y s t a l (~) containing a d i s p e r s i o n of a fluid p h a s e (L2) which can c r e a t e s u f f i c i e n t p r e s s u r e to o v e r c o m e the d i s d i f f e r s f r o m the p h a s e of the o r i g i n a l m e l t (L~). It is j o i n i n g p r e s s u r e and l e a d to i n c o r p o r a t i o n of the nonc l a i m e d that m o s t s o l i d s do not e n t r a p liquid at the wetting p h a s e into the s o l i d . Some a s p e c t s of the monotectic reaction. 4 t h e o r y have b e e n t e s t e d q u a n t i t a t i v e l y , s A p p l y i n g t h i s B e c a u s e one c o m p o s i t e p h a s e is liquid t h e r e a r e t h e o r y to m o n o t e c t i c s l e a d s to the p r e d i c t i o n that s p e c i a l p r o b l e m s in m o n o t e c t i c c o m p o s i t e g r o w t h c o m p o s i t e s can be grown e v e n if L2 is a nonwetting that a r e in a d d i t i o n to t h o s e that a p p l y to e u t e c t i c liquid if the g r o w t h v e l o c i t y is l a r g e enough to o v e r c o m p o s i t e growth. T h e s o l i d p h a s e m u s t be s t r u c t u r a l l y c o m e the d i s j o i n i n g p r e s s u r e . connected. F o r i n s t a n c e a l a m e l l a r m o r p h o l o g y i s not We thus have two p r e d i c t i o n s about the p o s s i b i l i t y l i k e l y to r e s u l t in a c o m p o s i t e , while a d i s p e r s i o n of of g r o w i n g m o n o t e e t i c c o m p o s i t e s . T h e y d i f f e r only liquid r o d s in a s o l i d b l o c k would. E x p e r i e n c e with when L~ i s a w e t t i n g liquid, in which c a s e C h a d w i c k e u t e e t i c s l e a d s one to p r e d i c t a r o d m o r p h o l o g y only p r e d i c t s no c o m p o s i t e s w i l l o c c u r and the o t h e r when the v o l u m e f r a c t i o n of the s o l i d is high. V o l u m e t h e o r y p r e d i c t s that c o m p o s i t e s can
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