Cheat Sheet Test #2

Cheat Sheet Test#2 - Diffusion flux(J The quantity of mass diffusing through and perpendicular to a unit cross-sectional area of material per unit

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Diffusion flux ( J ). The quantity of mass diffusing through and perpendicular to a unit cross-sectional area of material per unit time. Driving force. The impetus behind a reaction, such as diffusion, grain growth, or a phase transformation. Usually attendant to the reaction is a reduction in some type of energy (e.g., free energy). Fick’s laws – See side Interdiffusion. Diffusion of atoms of one metal into another metal. Nonsteady-state diffusion. The diffusion condition for which there is some net accumulation or depletion of diffusing species. The diffusion flux is dependent on time. Self-diffusion. Atomic migration in pure metals. Steady-state diffusion. The diffusion condition for which there is no net accumulation or depletion of diffusing species. The diffusion flux is independent of time. Vacancy diffusion. The diffusion mechanism wherein net atomic migration is from lattice site to an adjacent vacancy. Anelastic deformation. Time-dependent elastic (nonpermanent) deformation. Design stress ( σ d ). Product of the calculated stress level (on the basis of estimated maximum load) and a design factor (which has a value greater than unity). Used to protect against unanticipated failure. shear stress. Edge, screw, and mixed dislocations are possible. Activation energy ( Q ). The energy required to initiate a reaction, such as diffusion. Carburizing. The process by which the surface carbon concentration of a ferrous alloy is increased by diffusion from the surrounding environment. Concentration gradient ( dC/dx ). The slope of the concentration profile at a specific position. units in combination along its molecular chains. Concentration profile. The curve that results when the concentration of a chemical species is plotted versus position in a material. Diffusion.
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This note was uploaded on 03/26/2008 for the course ENGR 213 taught by Professor Dr.stubbs during the Fall '04 term at Texas A&M.

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