I consider the ductility as uniform elongation. To understand this, first we need to understand relationship between strain hardening exponent(n) and true strain. We know that true strain = n. ( you can refer dieter for the derivation) That means if strain hardening exponent increase true strain incRead more
I consider the ductility as uniform elongation. To understand this, first we need to understand relationship between strain hardening exponent(n) and true strain. We know that true strain = n. ( you can refer dieter for the derivation) That means if strain hardening exponent increase true strain increases. That means uniform elongation increases. The strain hardening exponent is higher for smaller grain size material. If we thing dislocation point of view if grain size is larger, the dislocation pile up will be more. That means, for large grain size the no.of dislocation pile up at the grain boundary is high compare to small grain size. Becoz of large no.of dislocations pile up, there will be high stress concentration which leads to nucleate crack. But in small grain size there is no enough stress to nucleate crack. That’s why small grain size materials has higher uniform elongation.
Fine grain structure having more grain boundry area than coarser structure. So, stress required to move the dislocation through finer structure is larger than coaser. So, fine grain structure have more ductility than coaser structure.
Fine grain structure having more grain boundry area than coarser structure. So, stress required to move the dislocation through finer structure is larger than coaser. So, fine grain structure have more ductility than coaser structure.
Actually fine grain steels has less ductility then coarse grain steels because in fine grained steels The grain boundary area is large which acts as barriers to dislocation motion so it requires more stress to move a dislocation across large grain boundary area which leads to less ductility .WhereasRead more
Actually fine grain steels has less ductility then coarse grain steels because in fine grained steels The grain boundary area is large which acts as barriers to dislocation motion so it requires more stress to move a dislocation across large grain boundary area which leads to less ductility .Whereas in coarse grained steel the grain boundary area is less so the stress required to move the dislocation across less grain boundary area is small which leads to high ductility.
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I consider the ductility as uniform elongation. To understand this, first we need to understand relationship between strain hardening exponent(n) and true strain. We know that true strain = n. ( you can refer dieter for the derivation) That means if strain hardening exponent increase true strain incRead more
I consider the ductility as uniform elongation. To understand this, first we need to understand relationship between strain hardening exponent(n) and true strain. We know that true strain = n. ( you can refer dieter for the derivation) That means if strain hardening exponent increase true strain increases. That means uniform elongation increases. The strain hardening exponent is higher for smaller grain size material. If we thing dislocation point of view if grain size is larger, the dislocation pile up will be more. That means, for large grain size the no.of dislocation pile up at the grain boundary is high compare to small grain size. Becoz of large no.of dislocations pile up, there will be high stress concentration which leads to nucleate crack. But in small grain size there is no enough stress to nucleate crack. That’s why small grain size materials has higher uniform elongation.
See lessFine grain structure having more grain boundry area than coarser structure. So, stress required to move the dislocation through finer structure is larger than coaser. So, fine grain structure have more ductility than coaser structure.
Fine grain structure having more grain boundry area than coarser structure. So, stress required to move the dislocation through finer structure is larger than coaser. So, fine grain structure have more ductility than coaser structure.
See lessActually fine grain steels has less ductility then coarse grain steels because in fine grained steels The grain boundary area is large which acts as barriers to dislocation motion so it requires more stress to move a dislocation across large grain boundary area which leads to less ductility .WhereasRead more
Actually fine grain steels has less ductility then coarse grain steels because in fine grained steels The grain boundary area is large which acts as barriers to dislocation motion so it requires more stress to move a dislocation across large grain boundary area which leads to less ductility .Whereas in coarse grained steel the grain boundary area is less so the stress required to move the dislocation across less grain boundary area is small which leads to high ductility.
See less