Quiz2B_MSEG302 - Do all Problems QUIZ#2b (1 011100 Total...

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Unformatted text preview: Do all Problems QUIZ#2b (1 011100 Total Points) MSEG 302 Write your answers below the question required use the back of the page on resides. Namet Kf*t on this paper. lf extra room is which a specific question r 3 (1 uh 1 . 8-1 ei^ I I 5 pts) Explain the three stages of annealing of metallic materials. Recovery: A low-temperature treatment that removes the residual stresses due to cold working without causing a change in dislocation density. The original cold-worked microstructure is composed of deformed grains containing alwge nurnber of tangled dislocations. When the metal is first heated, the additional thermal energy permits the dislocations to move and form the boundaries of a polygonaized subgrain structure. Recrystalli zation: A medium-temperature annealing heat treatment rapid rEpovery eliminates residual stresses and produces the polygonized,dislocation structure. New small grains then nucleate at the cell boundaries of the polygonized structure, eliminating most of the dislocations. Because the number of dislocations is greatly reduced, the recrystallizated metal has low strength but high ductility. Grain Growth: A higher-temperature annealing heat treatment, both recovery and recrystallization occur rapidly, producing a fine recrystallizedgrain structure. If the temperature is high enough, the grains begin to grow, with favored grains consuming the smaller grains. (a) G) (c) (d) Figure 8'16 The effect of annealing temperature on.the microstructure of cold-worked metals. (a) cotd-worked, (b) after re"ou"ry, ?"j-rri.i'ielrlstarrizatil; ;al;j;rtJr grain growth. {cI rrr5 r ' +Ll ut-.LLr \ * . ' 2. 3 . Do all Problems QUIZ #2b (1 011100 Total Points) MSEG 302 Write your answers below the question required use the back of the page on resides. Name: on this paper. lf extra room is which a specific question 8-1 (15 pts) Explain the three stages of annealing of metallic materials. Recovery: A low-temperature treatment that removes the residual stresses due to cold working without causing a change in dislocation density, The original cold-worked microstructure is composed of deformed grains containing alarge number of tangled dislocations. When the metal number of tangled dislocations....
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This note was uploaded on 02/01/2012 for the course MSEG 302 taught by Professor Snively during the Spring '08 term at University of Delaware.

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Quiz2B_MSEG302 - Do all Problems QUIZ#2b (1 011100 Total...

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