In the Late Classic Period Yaxchilan was one of the most powerful Maya cities along the course of the Usumacinta, with Piedras Negras as its major rival. Architectural styles in subordinate sites in the Usumacinta region demonstrate clear differences that mark a clear boundary between the two kingdoms.
Answered by The Community. Making the world better, one answer at a time. Steel is not usually considered a composite, as it is macroscopically homogeneous. However, some steel types, including classical iron-carbon steel, can be considered as metal-matrix composites, as they contain a second phase... sometimes.
Photo by: mipan. Steel is an alloy of iron with about 1 percent carbon. It may also contain other elements, such as manganese. Whereas pure iron is a relatively soft metal that rusts easily, steel can be hard, tough, and corrosion-resistant. Used to make almost everything from skyscraper girders, automobiles, and appliances to thumb tacks and paper clips, steel is one of the world's most vital materials.