J. Phys. IV France 110 (2003) 851
Laser shock compression of copper monocrystals: Mechanisms for dislocation and void generationM.A. Meyers1, M.S. Schneider1, B.K. Kad1, V.A. Lubarda1, F. Gregori2, D.H. Kalantar3 and B.A. Remington3
1 University of Catifornia, San Diego, La Jolla, CA 92093, U.S.A.
2 University of Paris 13, France
3 Lawrence Livermore National Laboratory, Livermore, CA 94450, U.S.A.
Copper with two orientations ( and ) was subjected to high intensity laser (energy levels of 40-300 J; energy densities of 15-70 MJ/m 2 and durations below 10 ns). The defects created are characterized by transmission electron microscopy. An orientation-dependent threshold stress for twinning is observed. The results are rationalized in terms of a criterion in which slip and twinning are considered as competing mechanisms. A constitutive description is applied to the two orientations, incorporating both slip and twinning. The predictions are in agreement with experiments. The threshold stress for twinning in the  orientation is 20-40 GPa, whereas the one for the  orientation is 40-60 GPa. The threshold stress is calculated, considering the effect of shock heating. The constitutive description provides a rationale for the experimental results; the calculated thresholds are 18 GPa for  and 25 GPa for . A mechanism for void generation and growth based on the emission of geometrically necessary dislocations is proposed and analytically formulated.
© EDP Sciences 2003