Hints for imaging phases in steels: some techniques learned from experience can help...

The microstructure of metals and alloys can be quite complex, particularly in certain alloy systems such as iron-based alloys. A good understanding of physical metallurgy, the role of composition and processing on structure formation and modification, and an idea of the approximate expected hardness of different phases or constituents will help narrow the range of possible phases that might be present.

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However, this knowledge is sometimes not enough to enable even skilled metallographers to reveal and identify important phases. For example