Alloy Phase Diagram Database™
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Welcome to Alloy Phase Diagram Database™

The ASM Alloy Phase Diagram Database allows subscribers to explore, search and view more than 36,500 binary and ternary phase diagrams and associated phase data for more than 6200 systems from their Web browsers.

To get started, enter one or more elements in the boxes at the top of the screen and click Go, or select Explore to browse by elements and systems, or select Search to build targeted queries.

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Metastable Phases. The three types of equilibrium are stable, metastable, and unstable. From a thermodynamic standpoint, an alloy at equilibrium is at the bottom of a free energy "well." However, there may be many such wells that a system could be in depending on the phases it contains. If it is in the lowest possible well, then it is in stable equilibrium. If it is in a higher well then it is in metastable equilibrium. The system can be in a metastable state for a short time (nanoseconds) or a long time (millions of years). It all depends on the time needed to nucleate and form a more stable phase or phases. Rapid freezing is a common method of producing metastable structures, but some (such as Fe3C, or "cementite") are produced at moderately slow cooling rates. The diagram shows both stable (solid lines) and metastable (dashed lines) equilibrium in the C-Fe system.

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ASM Alloy Phase Diagram Database, P. Villars, editor-in-chief; H. Okamoto and K. Cenzual, section editors.

ASM International, Materials Park, OH, 44073, USA