Maps of phases present at given temperature and composition.
Phase diagrams plot equilibrium phases against temperature and composition. Features: liquidus, solidus, solvus, eutectic, peritectic, eutectoid. Use them to predict phases, compositions and microstructure after slow cooling. Binary isomorphous (Cu-Ni), eutectic (Pb-Sn) are classic.
Solder Pb-Sn eutectic melts sharply at 183 °C.
Phase diagrams show which phases exist at each temperature and composition, which tells you what microstructure an alloy will have.
Maps of phases present at given temperature and composition.
Phase diagrams show which phases exist at each temperature and composition, which tells you what microstructure an alloy will have.
The phases that are stable at each temperature and composition at equilibrium, along with the boundaries between phases.
Cooling is often faster than equilibrium, so non-equilibrium phases and segregation can form.
Typical applications include predicting the phases present in a brass casting at room temperature, selecting a solder composition that melts at a suitable temperature and designing a heat treatment that forms the desired phase mix in an alloy.
Study "Recovery, recrystallisation and grain growth" first (topic 14 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
Gibbs phase rule. Tie lines. Invariant reactions.
Solder Pb-Sn eutectic melts sharply at 183 °C.
The next topic is "Lever rule", which builds directly on this one.
It is classed as Beginner in Materials & Chemical (topic 15 of 100). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
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