TY  - EJOU
AU  - Lassila, L. M. Hsiung, D. H. 

TI  - Initial Dislocation Structure and Dynamic Dislocation Multiplication In Mo Single Crystals
T2  - Computer Modeling in Engineering \& Sciences

PY  - 2002
VL  - 3
IS  - 2
SN  - 1526-1506

AB  - Initial dislocation structures in as-annealed high-purity Mo single crystals, and deformation substructures of the crystals compressed at room temperature under different strain rates have been examined and studied in order to elucidate the physical mechanisms of dislocation multiplication and motion in the early stages of plastic deformation. The initial dislocation density was measured to be in a range of 10<sup>6</sup> ~ 10<sup>7</sup> cm<sup>−2</sup>. More importantly numerous grown-in superjogs were observed along screw dislocation lines. After testing in compression, dislocation density (mainly screw dislocations) increased to 10<sup>7</sup> ~ 10<sup>8</sup> cm<sup>−2</sup>. Besides, the formation of dislocation dipoles (debris) due to the nonconservative motion of jogged screw dislocations was found to be dependent of the strain rates. While little dislocation dipoles (debris) were found in the crystal tested quasistatically(10<sup>−3</sup> s<sup>−1</sup>), more cusps along screw dislocation lines and numerous dislocationdipoles (debris) were observed in the crystal compressed under the strain rate of 1s<sup>−1</sup>. Physical mechanisms for dislocation multiplication as well as dipole formation from jogged screw dislocations under different strain rate conditions are accordingly proposed and discussed.

KW  - 

DO  - 10.3970/cmes.2002.003.185