  Fracture material is seriously problem in daily life, and it has connection
with mechanical properties itself. The mechanical properties is belief depend
on dislocation movement and crack propagation in the crystal. Information about
this is very important to characterize the material. In FCC crystal structure
the competition between crack propagation and dislocation wake is very
interesting, in a ductile material like copper (Cu) dislocation can be seen in
room temperature, but in a brittle material like Si only cracks can be seen
observed. Different techniques were applied to material to study the mechanical
properties, in this study we did compression test in one direction. Combination
of simulation and experimental on cubic material are reported in this paper. We
found that the deflection of crack direction in Si caused by vacancy of
lattice,while compression stress on Cu cause the atoms displacement in one
direction. Some evidence of dislocation wake in Si crystal under compression
stress at high temperature will reported.
