Diagram Legend

Transformation diagrams
There are two main types of transformation diagram that are helpful in selecting the optimum alloy and processing route to achieve a given set of properties. These are time-temperature transformation (TTT) and continuous cooling transformation (CCT) diagrams. CCT diagrams are generally more appropriate for engineering applications as components are cooled (air cooled, furnace cooled, quenched etc.) from a processing temperature as this is more economic than transferring to a separate furnace for an isothermal treatment.

Continuous cooling transformation (CCT) diagrams
Measure the extent of transformation as a function of time for a continuously decreasing temperature. In other words a sample is austenitised and then cooled at a predetermined rate and the degree of transformation is measured, for example by dilatometry. Obviously a large number of experiments is required to build up a complete CCT diagram.

Continuous-heating-transformation (CHT) diagram

Continuous cooling precipitation (CCP) diagram

Time-temperature transformation (TTT) diagram
Measure the rate of transformation at a constant temperature. In other words a sample is austenitised and then cooled rapidly to a lower temperature and held at that temperature whilst the rate of transformation is measured, for example by dilatometry. Obviously a large number of experiments is required to build up a complete TTT diagram.

Time-temperature embrittlement (TTE) diagram

Time-temperature precipitation (TTP) diagram

Time-temperature properties (TTP) diagram

Time-temperature sensitization (TTS) diagram

Time-temperature hardness (TTH) diagram

Temperature-phase stability (TPS) diagram

Temperature-temperature aging (TTA) diagram

Temperature-temperature oxidation (TTO) diagram

Temperature-temperature cracking (TTC) diagram

Temperature-temperature corrosion (TTC) diagram

Temperature-temperature nucleation (TTN) diagram

Temperature-temperature toughness (TTT) diagram

Temperature-temperature intergranular (TTI) diagram

Temperature-temperature crystallization (TTC) diagram

Temperature-temperature ordering (TTO) diagram

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