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Substitutional solid solution strengthening occurs when the solute atom is large enough that it can replace solvent atoms in their lattice positions. Some alloying elements are only soluble in small amounts, whereas some solvent and solute pairs form a solution over the whole range of binary compositions.
For this strengthening mechanism, solute atoms of one element are added to another, resulting in either substitutional or interstitial point defects in the crystal (see Figure on the right). The solute atoms cause lattice distortions that impede dislocation motion, increasing the yield stress of the material. Solute atoms have stress fields ...
For substitutional solid solutions, the Hume-Rothery rules are as follows: The atomic radius of the solute and solvent atoms must differ by no more than 15%: [1] % = % %. The crystal structures of solute and solvent must be similar.
In metal alloys with substitutional solute elements, such as aluminum-magnesium alloys, dynamic strain aging leads to negative strain rate sensitivity which causes instability in plastic flow. [4] The diffusion of solute elements around a dislocation can be modeled based on the energy required to move a solute atom across the slip plane of the ...
The IUPAC definition of a solid solution is a "solid in which components are compatible and form a unique phase". [3]The definition "crystal containing a second constituent which fits into and is distributed in the lattice of the host crystal" given in refs., [4] [5] is not general and, thus, is not recommended.
Strengthening mechanisms that alter the strength of a material include work hardening, solid solution strengthening, precipitation hardening, and grain boundary strengthening. Strengthening mechanisms are accompanied by the caveat that some other mechanical properties of the material may degenerate in an attempt to make a material stronger.
In the crystal solid state, diffusion within the crystal lattice occurs by either interstitial or substitutional mechanisms and is referred to as lattice diffusion. [1] In interstitial lattice diffusion, a diffusant (such as C in an iron alloy), will diffuse in between the lattice structure of another crystalline element.
where is the diffusivity of the solute atom in the host material, is the atomic volume, is the velocity of the dislocation, is the diffusion flux density, and is the solute concentration. [5] The existence of the Cottrell atmosphere and the effects of viscous drag have been proven to be important in high temperature deformation at intermediate ...