Grain Orientation:

Another significant property of the grains is their orientation. Below figure represents a random arrangement of the grains like which no one direction inside the grains is aligned along with the external boundaries of the metal sample. This random orientation can be obtained through cross rolling the material. It might develop a grain-oriented structure in the rolling direction if such a sample were rolled sufficiently in one direction that was display in the figure. This is known as preferred orientation. In several cases, preferred orientation is extremely desirable, other than in other instances, it could be most harmful.  For instance, preferred orientation in uranium fuel elements could result in catastrophic changes in dimensions in during use in a nuclear reactor.

Figure: Grain Orientation

(a) Random (b) Preferred