A LOW TEMPERATURE COLD WORK INTERNAL-FRICTION PEAK IN A1-0.5 Wt

I . E x p e r i m e n t . I n t e r n a l f r i c t i o n m e a s u r e m e n t s w e r e made w i t h a n i n v e r t e d pendulum by f r e e d e c a y method . I n s i t u t e n s i l e d e f o r m a t i o n was c a r r i e d o u t by an e l e c t r o m a g n e t i c s e t up a n d t h e t e n s i l e f o r c e a p p l i e d t o t h e s p e c i m e n c a n b e r e g u l a t e d c o n t i n u o u s l y by c h a n g i n g t h e m a g n i t u d e of t h e e l e c t r i c c u r r e n t p a s s i n g t h r o u g h a n i n d u c t i o n c o i l . The e l o n g a t i o n o f t h e s p e c i m e n was m e a s u r e d b y a r e a d i n g t e l e s c o p e . The AI-0.5 w t % ( 0 . 19 a t %) G a s p e c i m e n s w e r e p r e p a r e d b y mel t i n g 99 .999 aluminum and 9 9 . 9 9 Ga Cproduced i n C h i n a ) i n a vacuum i n d u c t i o n f u r n a c e . The i n g o t o b t a i n e d was r o l l e d and d r a w n i n t o w i r e s . The f i n a l c o l d w o r k i n g was made by c o l d d r a w i n g a r o d of d i a m e t e r 2.6rnm t o 0.85 mm. T h i s c o r r e s p o n d s t o a c o l d w o r k i n g of 8 9 % r e d u c t i o n i n a r e a . The w i r e was a n n e a l e d a t 4 0 0 ' ~ f o r o n e h o u r and was u s e d a s t h e i n i t i a l s t a t e of t h e s p e c i m e n . 2 . R e s u l t s .( a ) T e m p e r a t u r e i n t e r n a l f r i c t i o n p e a k . An AI-0.5 w t % Ga Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1981538 C5-266 JOURNAL DE PHYSIQUE s p e c i m e n of d i a m e t e r 0 .84 m m was c o l d d r a w n a t 2 0 ° C t o a d i a m e t e r o f 0 . 8 0 mm ( c o r r e s p o n d i n g t o a c o l d w o r k i n g of 12% r e d u c t i o n i n a r e a ) and was t h e n mounted on t h e t o r s i o n pendulum. I n t e r n a l f r i c t i o n m e a s u r e m e n t s w e r e t a k e n r e p e a t e d l y w i t h d e c e n d i n g and a s c e n d i n g t e m p e r a t u r e s and t h e Q' T ( t e m p e r a t u r e ) c u r v e o b t a i n e d i s shown i n F i g . l. A p e a k a p p e a r e d a t -8 4-C w i t h f = 0 . 8 Hz. The h e i g h t of t h e p e a k was a b o u t I I O ~ .