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Microstructure checking by microscope.

A microscope is an instrument used to see objects that are too small to be seen by the naked eye.

Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope 🔬


The purpose here is to help identify the microstructures in steel using simple techniques based on the atomic mechanisms by which phases grow from austenite. Apart from their aesthetic beauty, microstructures become meaningful when examined in the context of their metallurgical theory.

The symbols used to represent each phase are as follows:

PhaseSymbol
Austeniteγ
Allotriomorphic ferriteα
Idiomorphic ferriteαI
PearliteP
Widmanstätten ferriteαw
Upper bainiteαb
Lower bainiteαlb
Acicular ferriteαa
Martensiteα'
Cementiteθ


θ


Austenite:-


Austenite has a cubic-close packed crystal structure, also referred to as a face-centred cubic structure 


Ferrite:-

Ferrite has a body-centred cubic crystal structure and cementite has an orthorhombic unit cell containing four formula units of Fe3C.


Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of ferrite (87.5 wt%) and cementite (12.5 wt%) 



Bainite:-

Bainite is a plate-like microstructure that forms in steels at temperatures of 125–550 °C (depending on alloy content



Martensite:-

Martensite is a phase of a material that is formed through diffusionless transformation, the transformation of one phase to another through subtle atomic rearrangements rather than diffusion. Martensite was originally named for a very hard, very brittle phase of steel that has needle-shaped microstructural features..





Our wealth of expertise in materials can be accessed to solve problems with typical applications including:

  • Grain size measurement
  • Identification of inclusions and specks
  • Porosity and bonding evaluation
  • Refractory attack mechanisms
  • Surface deposits and coatings
  • Development of interfaces on reaction
  • Unknown particles or materials identification
  • Evaluation of material processing
  • Performance evaluation and variability
  • Failure mechanisms and crack development
  • Evaluation of loci of failure.
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