Analyses on the Background of Dynamic Internal Friction and the Modulus Defect during Plastic Deformation

✍ Scribed by Cai, B. ;Kong, Q. P.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 180 KB
• Volume: 173
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/(sici)1521-396x(199906)173:2<365::aid-pssa365>3.0.co;2-e

✦ Synopsis

An analysis on the background of dynamic internal friction (DIF) and the modulus defect (DGaG) at low frequency during plastic deformation in single crystal specimens is given. The background Q À1

b is considered to be associated with the string vibration of immobile dislocations under a combined action of a unidirectional stress and an alternating stress. It is shown that the frequency dependence of Q À1 b is different from that of the components associated with multiplication and long-range motion of mobile dislocations. Hence Q À1 b can be resolved from the total DIF with measurements of different frequencies. It is found that the resolved Q À1 b is not a constant as usually treated in the literature, but is variable with strain (or time). A detailed analysis shows that the variation of Q À1 b during deformation is associated with the variation of dislocation density. The variation of modulus defect DGaG during deformation is shown to be also associated with the variation of dislocation density.