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.
In essence, steel is composed of iron and carbon, although it is the amount of carbon, as well as the level of impurities and additional alloying elements that determine the properties of each steel grade. The carbon content in steel can range from 0.1-1.5%, but the most widely used grades of steel contain only 0.1-0.25% carbon. 1  Elements such as manganese, phosphorus, and sulfur are found in all grades of steel, but, whereas manganese provides beneficial effects, phosphorus and sulfur are deleterious to steel's strength and durability.