What is martensite microstructure?
Martensite is a very hard form of steel crystalline structure. It is named after German metallurgist Adolf Martens. By analogy the term can also refer to any crystal structure that is formed by diffusionless transformation.
What is microstructure of steel?
The microstructure is predominantly martensite but also has allotriomorphic ferrite, Widmanstätten ferrite, bainite and pearlite. Notice that the spherical shape of a pearlite colony is obvious in this sample because of the lack of impingment.
What is a pearlite microstructure?
Pearlite is essentially a composite microstructure consisting of cementite layers (which are hard and brittle) sandwiched between ferrite layers (which are soft and ductile).
What is the martensitic phase?
The martensitic transformation is a displacive phase transition and it occurs by coordinated shifts of atoms but, there is no long range diffusion during the phase change. This structural transition can proceed through an intermediate phase.
What is the hardest microstructure?
Martensite
Martensite: the hardest and strongest microstructure, yet the most brittle.
What microstructure tells us?
Microstructure are material structures seen at the micro level. Specifically, they are structures of an object, organism, or material as revealed by a microscope at magnifications greater than 25 times. When typically mentioned, the microstructure are defects, impurities, grains, and grain boundary.
What makes up the microstructure of martensitic steel?
Martensitic microstructures that are of various carbon contents and tempered at various temperatures not only compose the microstructure of through-hardened steel parts, but also are major components, in some form or another, of other heat-treated steel systems.
Why are martensitic stainless steel used in medical devices?
Thus they are capable of developing a wide range of mechanical properties (i.e., high hardness for cutting instruments and lower hardness with increased toughness for load-bearing applications). Martensitic stainless steels used in medical devices usually contain up to 1% nickel.
What are the disadvantages and advantages of martensite?
The microstructure of martensite contains many needle-shaped features, which cause martensite to be very brittle. While the main disadvantage of martensite is that it’s very brittle, martensite is desirable because it’s also very hard.
What kind of SCC does martensitic stainless steel have?
The SCC for martensitic stainless steel depends on yield strength. The martensitic stainless steel with a higher yield strength has a high sensitivity to SCC. Fig. 9. Domains of active dissolution and localized corrosion for 13Cr and modified 13Cr martensitic stainless steel indicating the occurrence of SSC and SCC.
