The orientation of crystallites can be random with no preferred direction, called random texture, or preferred, possibly due to growth and processing conditions. Random orientation can be obtained by crossrolling the material. If such a sample were rolled sufficiently in one direction, it might developa grain-oriented structure in the rolling direction. This is called preferred orientation. In many cases, preferred orientation is very desirable, but in other instances, it can be most harmful. For example, preferred orientation in uranium fuel elements can result in catastrophic changes in dimensions during use in a nuclear reactor.
Special reference: U.S. Department of Energy, Material Science. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.