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Investigating Microstructural Effects on Hall-Petch Relationship of Mg-4Al Alloy

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Investigating Microstructural Effects on Hall-Petch Relationship of Mg-4Al Alloy /
作者:	Taheri Andani, Mohsen.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2022,
面頁冊數:	157 p.
附註:	Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
Contained By:	Dissertations Abstracts International84-01B.
標題:	Materials science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29275223
ISBN:	9798438781554

Investigating Microstructural Effects on Hall-Petch Relationship of Mg-4Al Alloy
Taheri Andani, Mohsen.

Investigating Microstructural Effects on Hall-Petch Relationship of Mg-4Al Alloy - Ann Arbor : ProQuest Dissertations & Theses, 2022 - 157 p.

Source: Dissertations Abstracts International, Volume: 84-01, Section: B.

Thesis (Ph.D.)--University of Michigan, 2022.

This item must not be sold to any third party vendors.

Grain size strengthening, referred to as the Hall-Petch effect, is a common strategy to improve the yield strength of magnesium (Mg) alloys. Several theoretical studies have reported that the geometry and structure of grain boundaries in polycrystalline materials could impose a significant effect on the Hall-Petch slope. However, experimental observations are primarily limited by the ability of the techniques to accurately quantify the grain boundary barrier strength to dislocation glide and validate these theoretical models. Using high-resolution electron backscatter diffraction (HR-EBSD), the local stress tensor ahead of a slip band blocked by a grain boundary was quantified and coupled with a continuum dislocation pile-up model to assess the barrier strength of specific grain boundaries to specific slip systems, referred to as micro-Hall-Petch coefficient. For basal slip system in a deformed Mg-4Al alloy, the micro-Hall-Petch coefficient (\uD835\uDC58\uD835\uDF07\uD835\uDC4F\uD835\uDC4E\uD835\uDC60\uD835\uDC4E\uD835\uDC59) varied significantly, from 0.054 to 0.184 MPa−m\uD835\uDFCF/\uD835\uDFD0 for nine different grain boundaries and for the prismatic slip systems the micro-Hall-Petch coefficients values ( \uD835\uDC58\uD835\uDF07\uD835\uDC5D\uD835\uDC5F\uD835\uDC56\uD835\uDC60\uD835\uDC5A\uD835\uDC4E\uD835\uDC61\uD835\uDC56\uD835\uDC50) vary from 0.138 MPa. m\uD835\uDFCF/\uD835\uDFD0 to 0.685 MPa. m\uD835\uDFCF/\uD835\uDFD0 , which are almost three times larger than the calculated values for the basal micro-Hall-Petch. These results were correlated with geometric descriptors of the respective grain boundaries, with three-dimensional GB profile additionally measured via focused ion beam milling. It was found that the angle between the two slip plane traces on the grain boundary plane was the most sensitive parameter affecting \uD835\uDC58\uD835\uDF07\uD835\uDC4F\uD835\uDC4E\uD835\uDC60\uD835\uDC4E\uD835\uDC59 and \uD835\uDC58\uD835\uDF07\uD835\uDC5D\uD835\uDC5F\uD835\uDC56\uD835\uDC60\uD835\uDC5A\uD835\uDC4E\uD835\uDC61\uD835\uDC56\uD835\uDC50, followed by the angle between the slip directions. A functional form for calculation of \uD835\uDC58\uD835\uDF07\uD835\uDC4F\uD835\uDC4E\uD835\uDC60\uD835\uDC4E\uD835\uDC59 and \uD835\uDC58\uD835\uDF07\uD835\uDC5D\uD835\uDC5F\uD835\uDC56\uD835\uDC60\uD835\uDC5A\uD835\uDC4E\uD835\uDC61\uD835\uDC56\uD835\uDC50 depending on these two angles is proposed to augment crystal plasticity constitutive models with slip resistance dependent on some measure of the grain size. The method to incorporate the micro Hall-Petch equation into crystal plasticity constitutive models accounting for the microstructural features to understand the coupling between grain size, texture and loading direction was presented. A rate-dependent crystal plasticity model implemented into the open-source PRISMS-CPFE plasticity code is adopted for crystal plasticity simulations. The effect of grain size and texture is accounted for by modifying the slip resistances of individual basal and prismatic slip systems based on the micro Hall-Petch equation. This modification endows each microstructural point with a slip system-level grain size and maximum compatibility factor which are used to modify the slip resistance. Comparisons in the Hall-Petch coefficients are presented between predicted stress-strain curves using original parameters from previous work and subsequently calibrated parameters. This approach provides the foundation to quantitatively model more complicated scenarios of coupling between grain size, texture and loading direction in the plasticity of Mg alloys.

ISBN: 9798438781554Subjects--Topical Terms:

543314
Materials science.
Subjects--Index Terms:

Hall-Petch effect

Investigating Microstructural Effects on Hall-Petch Relationship of Mg-4Al Alloy
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100 1 $a Taheri Andani, Mohsen. $3 3690282
245 1 0 $a Investigating Microstructural Effects on Hall-Petch Relationship of Mg-4Al Alloy
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300 $a 157 p.
500 $a Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
500 $a Advisor: Misra, Amit.
502 $a Thesis (Ph.D.)--University of Michigan, 2022.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a Grain size strengthening, referred to as the Hall-Petch effect, is a common strategy to improve the yield strength of magnesium (Mg) alloys. Several theoretical studies have reported that the geometry and structure of grain boundaries in polycrystalline materials could impose a significant effect on the Hall-Petch slope. However, experimental observations are primarily limited by the ability of the techniques to accurately quantify the grain boundary barrier strength to dislocation glide and validate these theoretical models. Using high-resolution electron backscatter diffraction (HR-EBSD), the local stress tensor ahead of a slip band blocked by a grain boundary was quantified and coupled with a continuum dislocation pile-up model to assess the barrier strength of specific grain boundaries to specific slip systems, referred to as micro-Hall-Petch coefficient. For basal slip system in a deformed Mg-4Al alloy, the micro-Hall-Petch coefficient (\uD835\uDC58\uD835\uDF07\uD835\uDC4F\uD835\uDC4E\uD835\uDC60\uD835\uDC4E\uD835\uDC59) varied significantly, from 0.054 to 0.184 MPa−m\uD835\uDFCF/\uD835\uDFD0 for nine different grain boundaries and for the prismatic slip systems the micro-Hall-Petch coefficients values ( \uD835\uDC58\uD835\uDF07\uD835\uDC5D\uD835\uDC5F\uD835\uDC56\uD835\uDC60\uD835\uDC5A\uD835\uDC4E\uD835\uDC61\uD835\uDC56\uD835\uDC50) vary from 0.138 MPa. m\uD835\uDFCF/\uD835\uDFD0 to 0.685 MPa. m\uD835\uDFCF/\uD835\uDFD0 , which are almost three times larger than the calculated values for the basal micro-Hall-Petch. These results were correlated with geometric descriptors of the respective grain boundaries, with three-dimensional GB profile additionally measured via focused ion beam milling. It was found that the angle between the two slip plane traces on the grain boundary plane was the most sensitive parameter affecting \uD835\uDC58\uD835\uDF07\uD835\uDC4F\uD835\uDC4E\uD835\uDC60\uD835\uDC4E\uD835\uDC59 and \uD835\uDC58\uD835\uDF07\uD835\uDC5D\uD835\uDC5F\uD835\uDC56\uD835\uDC60\uD835\uDC5A\uD835\uDC4E\uD835\uDC61\uD835\uDC56\uD835\uDC50, followed by the angle between the slip directions. A functional form for calculation of \uD835\uDC58\uD835\uDF07\uD835\uDC4F\uD835\uDC4E\uD835\uDC60\uD835\uDC4E\uD835\uDC59 and \uD835\uDC58\uD835\uDF07\uD835\uDC5D\uD835\uDC5F\uD835\uDC56\uD835\uDC60\uD835\uDC5A\uD835\uDC4E\uD835\uDC61\uD835\uDC56\uD835\uDC50 depending on these two angles is proposed to augment crystal plasticity constitutive models with slip resistance dependent on some measure of the grain size. The method to incorporate the micro Hall-Petch equation into crystal plasticity constitutive models accounting for the microstructural features to understand the coupling between grain size, texture and loading direction was presented. A rate-dependent crystal plasticity model implemented into the open-source PRISMS-CPFE plasticity code is adopted for crystal plasticity simulations. The effect of grain size and texture is accounted for by modifying the slip resistances of individual basal and prismatic slip systems based on the micro Hall-Petch equation. This modification endows each microstructural point with a slip system-level grain size and maximum compatibility factor which are used to modify the slip resistance. Comparisons in the Hall-Petch coefficients are presented between predicted stress-strain curves using original parameters from previous work and subsequently calibrated parameters. This approach provides the foundation to quantitatively model more complicated scenarios of coupling between grain size, texture and loading direction in the plasticity of Mg alloys.
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650 4 $a Materials science. $3 543314
650 4 $a Physical chemistry. $3 1981412
650 4 $a Mechanics. $3 525881
653 $a Hall-Petch effect
653 $a Magnesium alloys
653 $a Slip resistance
653 $a Texture
653 $a Loading direction
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690 $a 0346
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710 2 $a University of Michigan. $b Mechanical Engineering. $3 2104815
773 0 $t Dissertations Abstracts International $g 84-01B.
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791 $a Ph.D.
792 $a 2022
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29275223