martensite

enUK

mar·ten·site

M0125600 (mär′tn-zīt′)n. A solid solution of iron and up to one percent of carbon, the chief constituent of hardened carbon tool steels.

[After Adolf Martens (1850-1914), German metallurgist.]

mar′ten·sit′ic (-zĭt′ĭk) adj.

martensite

(ˈmɑːtɪnˌzaɪt) n (Metallurgy) metallurgy a constituent formed in steels by rapid quenching, consisting of a supersaturated solid solution of carbon in iron. It is formed by the breakdown of austenite when the rate of cooling is large enough to prevent pearlite forming[C20: named after Adolf Martens (died 1914), German metallurgist] martensitic adj ˌmartenˈsitically adv

mar•tens•ite

(ˈmɑr tnˌzaɪt)

n. a magnetic microconstituent of carbon steels, formed by decomposition of austenite: found in all hardened tool steels. [1895–1900; after Adolf Martens (d. 1914), German metallurgist; see -ite¹] mar`ten•sit′ic (-ˈzɪt ɪk) adj.

Thesaurus

Noun

martensite - a solid solution of carbon in alpha-iron that is formed when steel is cooled so rapidly that the change from austenite to pearlite is suppressed; responsible for the hardness of quenched steelquenched steel - steel that has been hardened by immersing it in water or oil to cool itprimary solid solution, solid solution - a homogeneous solid that can exist over a range of component chemicals; a constituent of alloys that is formed when atoms of an element are incorporated into the crystals of a metal

Translations

Martensite

enUK

martensite

[′mär‚ten‚zīt] (metallurgy) A metastable transitional structure formed by a shear process during a phase transformation, characterized by an acicular or needlelike pattern; in carbon steel it is a hard, supersaturated solid solution of carbon in a body-centered tetragonal lattice of iron.

Martensite

the structure of crystalline solids arising as the result of a slip, diffusionless polymorphic transformation on cooling. It is named for the German specialist in physical metallurgy A. Martens (1850-1914).

As a result of a lattice deformation, known as cooperative displacement, during the transformation, a relief appears on the surface of the metal. Internal strain arises in the bulk and plastic deformation occurs, which limit crystal growth. The rate of growth reaches 10³ m/sec and is independent of temperature. Hence, the rate of martensite formation is usually limited by crystal nucleation. The reaction of the internal strain shifts crystal nucleation greatly below the thermodynamic phase equilibrium point and may stop the transformation at constant temperatures. Thus, the amount of martensite formed usually increases with an increase in supercooling.

Since the elastic energy must be minimal, martensite crystals take the shape of plates (needles in cross section) regularly oriented relative to the initial lattice. The internal strain is also reduced by plastic deformation and thus the crystal contains many dislocations (up to 10¹² cm^-2) or is split into twins with a thickness of 10-100 nanometers (100-1000 angstroms). Intragranular boundaries and dislocations strengthen martensite.

Martensite is a typical product of low-temperature polymorphic transformations in pure metals such as iron, cobalt, titanium, zirconium, and lithium; in solid solutions based on these metals; and in intermetallic compounds such as CuZn, Cu₃Al, NiTi, V₃Si, and AuCd.

Martensite in steel is a supersaturated Fe-C solution obtained by hardening from austenite. The ordered position of carbon atoms that results from martensite displacement transforms the body-centered lattice of a-iron from cubic to tetragonal. The distortion of the lattice near the interstitial atoms results in hardness. The tetragonality and the hardness increase with the carbon content. Hardness increases up to 1,000 HV (Vickers hardness).

Carbon martensite is the major structural component of most high-strength steels. The carbon content in the solid solution and the martensite subgranular structure change upon tempering, which is used for increasing the ductility of steel.

Carbon is the most important factor of martensite strength in steel. The strength of noncarbon maraging steel results from the separation of intermetallic compounds upon aging.

The physical characteristics of Fe-C martensite as an interstitial solid solution, the source of its high strength, and the kinetics of martensite formation were established by G. V. Kurdiumov.

M. A. SHTREMEL’

martensite

mar·ten·site

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mar•tens•ite

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Words related to martensite

noun a solid solution of carbon in alpha-iron that is formed when steel is cooled so rapidly that the change from austenite to pearlite is suppressed

Related Words