To study microstructures and mechanical properties of iron-carbon alloys of various compositions. Apparatus Universal testing machine, micrometer, Rockwell hardness tester, metallographic equipment, and a computer and microscope based digital camera. Background The microstructure that develops in a steel alloy depends on the carbon content and heat treatment.
Cementite is much harder but more brittle than ferrite.
Thus increasing the content of cementite results in a harder and stronger material. Fine pearlite exhibits greater hardness and strength than coarse pearlite because dislocations must pass through more boundaries during plastic deformation. This microstructure consists of spherelike particles of Fe3C embedded in a continuous a phase matrix. There is less boundary area per unit volume in spheroidite than in pearlite, and therefore this results in a relatively soft and weak material. Another microconstituent of the austenitic transformation is bainite , which is composed of very fine ferrite and cementite phases.