This research involves a three years study of dislocation structures developed in the near-surface regions of alpha brass by cyclic straining. This basic research explores the evolution of high dislocation density arrays and the relationship of these arrays to persistent slip band formation. The role of stacking fault energy in this process will be explored by varying the zinc content. Bauschinger and residual stresses will be studied as a function of plastic strain. The results of this research will allow development of a better understanding of fatigue crack initiation.