Unformatted text preview: strain reactions are usually repulsive, which causes the motion of a dislocation to be hindered by the presence of other dislocations. As dislocation density increases this resistance occurs at a greater scale and results in the drop in yield strength. 3) A) (delta)G = a 3 (delta)G V + 6a 2 y d(delta)G/da = 3a 2 (delta)G V + 12ay 0 = 3a 2 (delta)G V + 12ay a* = -4y/(delta)G V (delta)G* = (a*) 3 (delta)G V + 6(a*) 2 y = 32y 3 /((delta)G V 2 ) B) (delta)G* is greater for a cube because cubes have a higher surface to volume ratio when compared to spheres. 4) At this minimum Brinell hardness the tensile strength = 800 MPa, which would require a deformation of at least 13%CW. If the steel is cold worked to the level then the ductility would reach 15%EL, so it is possible to have steel at both of those values instantaneously....
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- Spring '07
- Tensile strength, Work hardening, dislocation density increases