THE BORDONI PEAK IN ALUMINIUM SINGLE CRYSTALS AT MHz FREQUENCIES

Abstract

The Bordoni peak i n high p u r i t y aluminium s i n g l e c r y s t a l s has been i n v e s t igated by measuring the attenuation o f l o n g i t u d i n a l waves a t 10 MHz, using a conventional u l t r a s o n i c pulse echo technique w i t h a s i n g l e quartz transducer. The c r y s t a l s , o f (100>, <110) and <111> o r i e n t a t i o n , were deformed by compression, and the temperature dependence o f the u l t r a s o n i c attenuation was measured a f t e r applying resolved shear stresses ranging up t o 60 ~r r m-~. The r e s u l t s lead t o the f o l l o w i n g conclusions: (i) t h e temperature o f the Bordoni peak i n aluminium s i n g l e c r y s t a l s i s e s s e n t i a l l y independent o f the orient a t i o n ; (i i) the temperature o f the peak decreases considerably as the p r i o r deformation was increased up t o a resolved shear stress near 28 ~m n-~, and then increases s l i g h t l y f o r higher p r i o r stresses, (i i i) t h e peak height increases w i t h increasing deformation and, (i v) the subsidiary peak appears o n l y a t low deformation.

The bordoni peak in silver single crystals at megahertz frequencies

“…However, in comparison with extensive results obtained from studying the Bordoni peak in copper single crystal [9,[17][18][19] and in aluminium single crystal [10][11], one can believe that our conclusion is valid i.e. However, in comparison with extensive results obtained from studying the Bordoni peak in copper single crystal [9,[17][18][19] and in aluminium single crystal [10][11], one can believe that our conclusion is valid i.e.…”