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Yield Point of Iron Materials in Dependence of Lattice Binding and Microstructure
Author(s) -
Hildebrand H.,
Hildebrand M.
Publication year - 2001
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/1521-4052(200111)32:11<858::aid-mawe858>3.0.co;2-o
Subject(s) - microstructure , grain size , materials science , lattice (music) , yield (engineering) , crystallography , lattice constant , metallurgy , chemistry , thermodynamics , mineralogy , physics , diffraction , acoustics , optics
Ferritic/perlitic iron materials with ∼ 0.35% C and alloying elements of the groups III A/B to VIII of the Periodic Table (PT) showed that values of the yield point, measured statically by tension tests, do not only depend on the kind of alloying element or its content, but that they also depend on the microstructure (grain size and phase arrangement of the second phase M 3 C) in polycrystals. In the same way that the minimum of lattice binding between two neighbouring atoms (or ions) of the same kind is at half distance between them and corresponds to the equilibrium, we can find the yield point of polycrystals at distinct grain sizes (after thermal treatment) as well. The yield point behaves like the Young modulus, which is an expression of lattice binding. It should be noted that added alloying elements can accelerate the grain growth, but there are also cases where these elements cause hindrance. To raise the yield point the non‐equilibrium states on both sides of the determined minimum of yield point should be used, which depends on the grain size (and heat‐treatment conditions). This is especially meaningful for the employment of steel sheets in the car industry.