Which of the following statements is true How do grain bound

Which of the following statements is true? How do grain boundaries affect the movement of dislocations? Slow down the movement of dislocation; Enhance the movement of dislocations; Have no effect on the movement of dislocations; All of these. A plastically deformed metal usually exhibit... lower strength, lower ductility; higher strength, lower ductility; lower strength, higher ductility; higher strength, higher ductility. When you anneal a piece of cold worked steel by heating it to a high temperature and then slowly cooling it down, which of the following changes will occur to its mechanical properties? Both the strength and the ductility will increase. Both the strength and the ductility will decrease. The strength will increase, but the ductility will decrease. The strength will decrease, but the ductility will increase.

Solution

1)B)enhance the moment of dislocation

2)B)higher strength, lower ductility

3)C)the strength will increase, but the ductility will decrease