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P o l y c r y s t a l l i n e a l u m i n u m and gold w i r e s of 99.999 pct p u r i t y were twisted, or fatigued with constant t o r s i o n a l s t r a i n a m p l i t u d e s , and the e l e c t r i c a l r e s i s t i v i t y and the torque m e a s u r e d at 4.2~ The d e f o r m e d s p e c i m e n s were a n n e a l e d for 1 hr at room t e m p e r a t u r e (aluminum) or at 100~ (gold), and the r e s i s t i v i t y m e a s u r e d at 4.2~ D u r i n g u n i d i r e c t i o n a l twisting the r e s i s t i v i t y i n c r e a s e s c o n t i n u a l l y , while d u r i n g fatigue with a c o n s t a n t s t r a i n amplitude it i n c r e a s e s and s a t u r a t e s at a level which is higher for l a r g e r a m p l i t u d e s . The p e r c e n t a g e of the induced r e s i s t i v i t y that r e c o v e r s d u r i n g the a n n e a l i n g is 100 in s p e c i m e n s fatigued with a sufficiently s m a l l a m p l i t u d e , and d e c r e a s e s as the amplitude i n c r e a s e s . Relative e f f i c i e n c i e s of point defect p r o d u c t i o n in the v a r i o u s m o d e s of d e f o r m a t i o n a r e obtained by c o n s i d e r i n g the a m o u n t s of r e c o v e r y after the d e f o r m a t i o n s and the c o r r e s p o n d i n g s t r a i n e n e r g i e s expended d u r i n g the d e f o r m a t i o n s . T H E study of the defect s t r u c t u r e s which a r e produced d u r i n g the fatigue of m e t a l s h a s r e c e i v e d much a t t e n tion in r e c e n t y e a r s . F a t i g u e - i n d u c e d d i s l o c a t i o n s u b s t r u c t u r e s have b e e n studied as a function of s t r a i n or s t r e s s amplitude, test t e m p e r a t u r e , and s t a c k i n g fault energy.~ P o i n t defects a r e a l s o produced d u r i n g fatigue, a s evidenced by o b s e r v a t i o n s of enhanced diffusion due to fatigue, 2'3 and by the influence of i n t e r m e d i a t e a n n e a l i n g on the fatigue h a r d e n i n g behavior.4-~ E l e c t r i cal r e s i s t i v i t y r e c o v e r y m e a s u r e m e n t s on fatigued s p e c i m e n s have a l s o i n d i c a t e d that l a r g e c o n c e n t r a t i o n s of point defects can be produced. 7 The objective of the p r e s e n t paper is to i n v e s t i g a t e the influence of the fatigue s t r a i n amplitude on the e l e c t r i c a l r e s i s t i v i t y change at 4.2~ and its r e c o v e r y . The r e s u l t s give additional i n f o r m a t i o n on the production of point def e c t s in fatigue. EXPERIMENTAL PROCEDURES AND RESULTS P o l y c r y s t a l l i n e 99.999 pct pure a l u m i n u m and gold w i r e s of 1 m m diam were used for the e x p e r i m e n t s . The e l e c t r i c a l r e s i s t i v i t y of the s p e c i m e n s was d e t e r m i n e d at 4.2~ with an a c c u r a c y b e t t e r than +1 • 10 -11 ohm c m , using a s t a n d a r d p o t e n t i o m e t r i c method. A Leeds and Northrup m i c r o v o l t p o t e n t i o m e t e r and a Keithley 147 n u l l - d e t e c t o r were used for