Added several citations and clarifications.
Okumaya devam et...
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| To give an example, consider a dislocation with a [[burgers vector]] of <math>\frac{a}{2}\left [ 1 \bar{1} 0 \right ]</math> traveling along a <math>\left \{ 1 1 1 \right \}</math> slip plane initially in the γ phase, where it is a perfect dislocation in that FCC structure. Since the γ' phase is [[primitive cubic]] instead of FCC due to the substitution of aluminum into the vertices of the unit cell, the perfect burgers vector along that direction in γ' is twice that of γ. For the <math>\frac{a}{2}\left [ 1 \bar{1} 0 \right ]</math> dislocation to enter the γ' phase, it will have to create a high energy [[Crystallographic defect|anti-phase boundary]], which will need another such dislocation along the plane to restore order (as the sum of the two dislocations would have the perfect <math>a \left [ 1 \bar{1} 0 \right ]</math> burgers vector)<ref name=":02">{{Cite book |last=Laughlin |first=David E. |title=Physical metallurgy |last2=Hono |first2=Kazuhiro |date=2014 |publisher=Elsevier |isbn=978-0-444-53770-6 |edition=5th edition |location=Amsterdam}}</ref>. | To give an example, consider a dislocation with a [[burgers vector]] of <math>\frac{a}{2}\left [ 1 \bar{1} 0 \right ]</math> traveling along a <math>\left \{ 1 1 1 \right \}</math> slip plane initially in the γ phase, where it is a perfect dislocation in that FCC structure. Since the γ' phase is [[primitive cubic]] instead of FCC due to the substitution of aluminum into the vertices of the unit cell, the perfect burgers vector along that direction in γ' is twice that of γ. For the <math>\frac{a}{2}\left [ 1 \bar{1} 0 \right ]</math> dislocation to enter the γ' phase, it will have to create a high energy [[Crystallographic defect|anti-phase boundary]], which will need another such dislocation along the plane to restore order (as the sum of the two dislocations would have the perfect <math>a \left [ 1 \bar{1} 0 \right ]</math> burgers vector)<ref name=":02">{{Cite book |last=Laughlin |first=David E. |title=Physical metallurgy |last2=Hono |first2=Kazuhiro |date=2014 |publisher=Elsevier |isbn=978-0-444-53770-6 |edition=5th edition |location=Amsterdam}}</ref>. |
| It is thus rather energy prohibitive for the dislocation to enter the γ' phase unless there are two of them in close proximity along the same plane. However, the [[Peach-Koehler force]] between identical dislocations along the same plane is repulsive, which makes this an unlikely configuration. One possible mechanism involved one of the dislocations being pinned against the γ' phase while the other dislocation in the γ phase [[Cross slip|cross-slips]] into close proximity of the pinned dislocation from another plane, allowing the pair of dislocations to push into the γ' phase<ref>{{Cite journal |last=León-Cázares |first=F.D. |last2=Schlütter |first2=R. |last3=Monni |first3=F. |last4=Hardy |first4=M.C. |last5=Rae |first5=C.M.F. |date=2022-12 |title=Nucleation of superlattice intrinsic stacking faults via cross-slip in nickel-based superalloys |url=https://doi.org/10.1016/j.actamat.2022.118372 |journal=Acta Materialia |volume=241 |pages=118372 |doi=10.1016/j.actamat.2022.118372 |issn=1359-6454}}</ref>. | It is thus rather energy prohibitive for the dislocation to enter the γ' phase unless there are two of them in close proximity along the same plane<ref>{{Cite journal |last=Ru |first=Yi |last2=Li |first2=Shusuo |last3=Zhou |first3=Jian |last4=Pei |first4=Yanling |last5=Wang |first5=Hui |last6=Gong |first6=Shengkai |last7=Xu |first7=Huibin |date=2016-08-11 |title=Dislocation network with pair-coupling structure in {111} γ/γ′ interface of Ni-based single crystal superalloy |url=https://www.nature.com/articles/srep29941 |journal=Scientific Reports |language=en |volume=6 |issue=1 |pages=29941 |doi=10.1038/srep29941 |issn=2045-2322 |pmc=PMC4980694 |pmid=27511822}}</ref>. However, the [[Peach-Koehler force]] between identical dislocations along the same plane is repulsive<ref>{{Cite journal |last=Eggeler |first=G. |last2=Dlouhy |first2=A. |date=1997-10-01 |title=On the formation of 〈010〉-dislocations in the γ′-phase of superalloy single crystals during high temperature low stress creep |url=https://www.sciencedirect.com/science/article/pii/S1359645497000840 |journal=Acta Materialia |volume=45 |issue=10 |pages=4251–4262 |doi=10.1016/S1359-6454(97)00084-0 |issn=1359-6454}}</ref>, which makes this a less favorable configuration. One possible mechanism involved one of the dislocations being pinned against the γ' phase while the other dislocation in the γ phase [[Cross slip|cross-slips]] into close proximity of the pinned dislocation from another plane, allowing the pair of dislocations to push into the γ' phase<ref>{{Cite journal |last=León-Cázares |first=F.D. |last2=Schlütter |first2=R. |last3=Monni |first3=F. |last4=Hardy |first4=M.C. |last5=Rae |first5=C.M.F. |date=2022-12 |title=Nucleation of superlattice intrinsic stacking faults via cross-slip in nickel-based superalloys |url=https://doi.org/10.1016/j.actamat.2022.118372 |journal=Acta Materialia |volume=241 |pages=118372 |doi=10.1016/j.actamat.2022.118372 |issn=1359-6454}}</ref><ref name=":4">{{Cite journal |last=Dodaran |first=M. |last2=Ettefagh |first2=A. Hemmasian |last3=Guo |first3=S. M. |last4=Khonsari |first4=M. M. |last5=Meng |first5=W. J. |last6=Shamsaei |first6=N. |last7=Shao |first7=S. |date=2020-02-01 |title=Effect of alloying elements on the γ’ antiphase boundary energy in Ni-base superalloys |url=https://www.sciencedirect.com/science/article/pii/S0966979519309227 |journal=Intermetallics |volume=117 |pages=106670 |doi=10.1016/j.intermet.2019.106670 |issn=0966-9795}}</ref>. |
| Further complicating analysis is that the burgers vector <math>\frac{a}{2}\left \langle 110 \right \rangle</math> family of dislocations are likely to decompose into [[Partial dislocation|partial dislocations]] in this alloy due to its low [[Stacking-fault energy|stacking fault energy]], such as dislocations with burgers vector of the <math>\frac{a}{6}\left \langle 211 \right \rangle</math> family ([[Partial dislocation#Shockley partial dislocations|Shockley partial dislocations]])<ref name=":02" />. The [[Stacking fault|stacking faults]] between these partial dislocations can further provide another obstacle to the movement of other dislocations, further contributing to the strength of the material. | Furthermore, the burgers vector <math>\frac{a}{2}\left \langle 110 \right \rangle</math> family of dislocations are likely to decompose into [[Partial dislocation|partial dislocations]] in this alloy due to its low [[Stacking-fault energy|stacking fault energy]], such as dislocations with burgers vector of the <math>\frac{a}{6}\left \langle 211 \right \rangle</math> family ([[Partial dislocation#Shockley partial dislocations|Shockley partial dislocations]])<ref name=":02" /><ref name=":4" />. The [[Stacking fault|stacking faults]] between these partial dislocations can further provide another obstacle to the movement of other dislocations, further contributing to the strength of the material. There are also more [[Slip (materials science)#Slip systems|slip systems]] that can be involved beyond the <math>\left \{ 1 1 1 \right \}</math> slip plane and <math>\left \langle 110 \right \rangle</math> slip direction<ref>{{Cite journal |last=Mayr |first=C. |last2=Eggeler |first2=G. |last3=Dlouhy |first3=A. |date=1996-03 |title=Analysis of dislocation structures after double shear creep deformation of CMSX6-superalloy single crystals at temperatures above 1000 °C |url=https://doi.org/10.1016/0921-5093(96)80002-5 |journal=Materials Science and Engineering: A |volume=207 |issue=1 |pages=51–63 |doi=10.1016/0921-5093(96)80002-5 |issn=0921-5093}}</ref>. |
| At elevated temperature, the free energy associated with the anti-phase boundary (APB) is considerably reduced if it lies on a particular plane, which by coincidence is not a permitted slip plane. One set of partial dislocations bounding the APB cross-slips so that the APB lies on the low-energy plane, and, since this low-energy plane is not a permitted slip plane, the dissociated dislocation is effectively locked. By this mechanism, the yield strength of γ' phase Ni<sub>3</sub>Al increases with temperature up to about 1000 °C. | At elevated temperature, the free energy associated with the anti-phase boundary (APB) is considerably reduced if it lies on a particular plane, which by coincidence is not a permitted slip plane. One set of partial dislocations bounding the APB cross-slips so that the APB lies on the low-energy plane, and, since this low-energy plane is not a permitted slip plane, the dissociated dislocation is effectively locked. By this mechanism, the yield strength of γ' phase Ni<sub>3</sub>Al increases with temperature up to about 1000 °C. |
| Initial material selection for blade applications in [[gas turbine]] engines included alloys like the [[Nimonic]] series alloys in the 1940s.<ref name="RCREED" />{{page needed|date=December 2016}} The early Nimonic series incorporated γ' Ni<sub>3</sub>(Al,Ti) [[precipitation (chemistry)|precipitates]] in a γ matrix, as well as various metal-carbon [[carbide]]s (e.g. Cr<sub>23</sub>C<sub>6</sub>) at the [[grain boundary|grain boundaries]]<ref>{{cite journal|first1=D.|last1=Bombač|first2=M.|last2=Fazarinc|first3=G.|last3=Kugler|first4=S.|last4=Spajić|title=Microstructure development of Nimonic 80A superalloys during hot deformation|journal=Materials and Geoenvironment|volume=55|issue=3|date=2008|pages=319–328|url=https://www.researchgate.net/publication/291124171|access-date=2020-03-08|via=ResearchGate}}</ref> for additional grain boundary strength. Turbine blade components were [[forging|forged]] until [[vacuum induction melting|vacuum induction]] [[casting]] technologies were introduced in the 1950s.<ref name="RCREED" />{{page needed|date=December 2016}} This process significantly improved cleanliness, reduced defects, and increased the strength and temperature capability. | Initial material selection for blade applications in [[gas turbine]] engines included alloys like the [[Nimonic]] series alloys in the 1940s.<ref name="RCREED" />{{page needed|date=December 2016}} The early Nimonic series incorporated γ' Ni<sub>3</sub>(Al,Ti) [[precipitation (chemistry)|precipitates]] in a γ matrix, as well as various metal-carbon [[carbide]]s (e.g. Cr<sub>23</sub>C<sub>6</sub>) at the [[grain boundary|grain boundaries]]<ref>{{cite journal|first1=D.|last1=Bombač|first2=M.|last2=Fazarinc|first3=G.|last3=Kugler|first4=S.|last4=Spajić|title=Microstructure development of Nimonic 80A superalloys during hot deformation|journal=Materials and Geoenvironment|volume=55|issue=3|date=2008|pages=319–328|url=https://www.researchgate.net/publication/291124171|access-date=2020-03-08|via=ResearchGate}}</ref> for additional grain boundary strength. Turbine blade components were [[forging|forged]] until [[vacuum induction melting|vacuum induction]] [[casting]] technologies were introduced in the 1950s.<ref name="RCREED" />{{page needed|date=December 2016}} This process significantly improved cleanliness, reduced defects, and increased the strength and temperature capability. |
Okumaya devam et...