Dislocation Slip Behavior of Ni Single Crystal Under Dynamic Compression

Face-centered-cubic Ni single crystal was compressed along [011] direction at a strain rate of 10³ s⁻¹, and microscopic characterization of slip bands was analyzed to investigate dynamical deformation mechanism of the Ni single crystal. By analyzing Schmid Factor and orientation of slip bands, the specific slip planes were revealed. Furthermore, by analysis of Schmid Factors and dimensions of the deformed sample, the slip directions are revealed, and the ratio of the slipping-induced displacement (D-ratio) related to each slip system were determined. For comparison, quasi-static compression (at a strain rate of 10⁻³ s⁻¹) along [011] direction was conducted to a same Ni single crystal sample. Results show that the dynamic deformation process (at a strain rate of 10³ s⁻¹) of Ni single crystal is accomplished via dislocation slip, and the activated slip systems under dynamic loading are proved to be (111) [1 ¯ 10] , (111) [1 ¯ 01] , (1 ¯ 11) [110] and (1 ¯ 11) [101]. Moreover, the quasi-static compression experimental results show the same slip systems, and the calculated slipping-induced displacement related to above 4 slip system have a ratio of nearly 1:3.8:3.8:1 under quasi-static compression. Thus, in a considerable strain rate range from 10⁻³ to 10³ s⁻¹, the activated slip systems and the ratio of their corresponding slipping-induced displacement are the same. However, experimental results show that, the slip bands on side surface of Ni single crystal subjected to dynamic compression is denser than that of the quasi-static compressed sample, indicating that the slip bands are formed more easily under dynamic loading condition.