Internal stresses induced by plastic shear deformation of Zr-(Cu,Ag)-Al bulk metallic glasses

Effective internal shear stress sigma(i) induced by torsional deformation of Zr(46)(Cu(4/5)Ag(1/5))(46)Al(8) and Zr(46)Cu(46)Al(8) bulk metallic glasses different by the glass-forming ability of the maternal melts has been determined by measurements of stress relaxation upon stepwise unloading. It has been found that the ratio sigma(i)/sigma(0) (sigma(0) is the initially applied shear stress) decreases upon increasing the temperature from approximate to 0.8 at T = 450K (T approximate to 0.64 x T(g)) to approximate to 0.08 at T = 638K (T approximate to 0.91 x T(g)) independently of sigma(0) and glass composition. The obtained result is in good agreement with earlier data obtained on ribbon metallic glasses. The origin of deformation-induced internal stresses and their connection with deformation mechanisms of metallic glasses has been briefly discussed. (C) 2011 Elsevier B.V. All rights reserved.