# Engineering: Dislocation and Deformation - Essay Example

Consider two edge dislocations of opposite sign and having slip planes that are separated by several atomic distances. Briefly describe the defect that results when these two dislocations become aligned with each other. When the two edge dislocations become aligned, a planar region of vacancies will exist between the dislocations. 7. 12 Consider a metal single crystal oriented such that normal to the slip plane and the slip direction are at angles 60 and 35 with the tensile axis.

If the critical resolved shear stress is 6. 2 will an applied stress of 12 cause the single crystal to yield? If not, what stress will be necessary? Since the resolved shear stress is less that the critical resolved shear stress, the single crystal will not yield. 7. 19 List the four major differences between deformation by twinning and deformation by slip relative to mechanism, conditions of occurrence, and final result. ) With slip deformation there Is no crystallography re orientation, whereas with twinning there Is are orientation 2) For slip, the atomic displacements occur In atomic pacing multiples, whereas for twinning, these displacements may be other than by atomic spacing multiples 3) Slip occurs In metals having many slip systems, whereas twinning occurs in metals having relatively few slip systems 4) Normally slip results In relatively large deformations, whereas only small deformations result for twinning. . 39 An specimen of some alloy has an average grain diameter of 0. 050 m. You are asked to reduce Its average grain diameter to 0. 020 m. Is this possible? If so, explain the procedures you would use and name the processes Involved. If It Is not possible, explain why. Yes, It Is possible to reduce the average grain diameter of an alloy specimen from 0. 050 m to 0. 020 m.

To do this, plastically deform the material at room temperature and then anneal It at an elevated temperature In order to allow and some grain growth to occur until the average grain diameter Is 0. 020 m. 1) With slip deformation there is no crystallography re orientation, whereas with twinning there is are orientation 2) For slip, the atomic displacements occur in atomic atomic spacing multiples 3) Slip occurs in metals having many slip systems, whereas in relatively large deformations, whereas only small deformations result for twinning. M. You are asked to reduce its average grain diameter to 0. 020 m. Is this involved. If it is not possible, explain why. Yes, it is possible to reduce the average grain diameter of an alloy room temperature and then anneal it at an elevated temperature in order to allow and some grain growth to occur until the average grain diameter is