Different materials have their own physical characteristics which determine how they will react to the reduction process
Ductile materials are not easily fractured but tend to tear into long strips. They are best reduced by shearing to ensure small particle size. Examples are cloth, rubber, soft plastics, paper, cardboard, or soft metals.
These are materials that are easily fractured (the opposite of ductile) or broken into shards. Examples are stone, glass, cast metals, hard plastics, or wood. Shredded friable materials tend to come out as small pieces rather than the long strips.
