eutectoid
Speech parts
1. eutectoid - Noun
2. eutectoid - Adjective
Meaning
eutectoid (not comparable)
Describing the phase-change reaction of an alloy in which, on cooling, a single solid phase transforms into two other solid phases.
eutectoid (plural eutectoids)
An alloy of a composition that undergoes the eutectoid transformation.
Phrases with the word
Examples
When steels with exactly 0.8% carbon (known as a eutectoid steel), are cooled, the austenitic phase (FCC) of the mixture attempts to revert to the ferrite phase (BCC).
In a hypereutectoid composition (greater than 0.8% carbon), the carbon will first precipitate out as large inclusions of cementite at the austenite grain boundaries and then when the composition left behind is eutectoid, the pearlite structure forms.
The inverse of this, when one solid phase transforms into two solid phases during heating, is called the eutectoid.
The same process, but beginning with a solid instead of a liquid is called a eutectoid transformation.