1. Suppose a metal single crystal is loaded (stressed) in the
[1 0 1] direction. a. If the critical resolved shear stress for this material is 0.34 MPa, what magnitude of applied stress is necessary for dislocations to begin to move in the (1 1 1)[-
1 1 0] slip system? b. If the slip system listed in part a is valid, does this metal have the FCC, HCP, or BCC crystal structure? 2. Suppose you have an FCC metal single crystal which is known to have a critical resolved shear stress of 55.2 MPa. a. Find the largest normal stress that could be applied to a bar of this material in the [
1 1 2] direction before dislocations begin to move in the
[1 0 -1] direction on the (1 1 1) plane. b. How does your answer change if it is a BCC crystal and the slip system is [
1 1 1](1 0 -1) (with the same


shear stress)? 3. Consider the crystal structure for CaTiO3 (the perovskite structure) in which Ca2+ ions are located at the simple cubic positions, O2- ions are located at the six face centers, and the Ti4+ ion is at the 1
/2, 1/
2, 1/
2 position. Determine the direction and length of the lowest-energy Burgers vector for this compound.