Estimation of micro-Hall-Petch coefficients for prismatic slip system in Mg-4Al as a function of grain boundary parameters

2021 ◽  
pp. 117613
Author(s):  
Mohsen Taheri Andani ◽  
Aaditya Lakshmanan ◽  
Veera Sundararaghavan ◽  
John Allison ◽  
Amit Misra
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Prismatic Slip

Influence of Grain Boundary on Activation of Slip Systems in Magnesium: Crystal Plasticity Analysis

2010 ◽  
Vol 654-656 ◽  
pp. 695-698 ◽  
Author(s):  
Tsuyoshi Mayama ◽  
Tetsuya Ohashi ◽  
Kenji Higashida
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Crystal Plasticity ◽  
Crystal Orientation ◽  
Basal Slip ◽  
Prismatic Slip ◽  
Shear Stresses ◽  
Slip Systems ◽  
Analysis Method ◽  
Pyramidal Slip

Crystal plasticity finite element analysis method considering the accumulation of geometrically necessary (GN) dislocations was applied to monotonic loading of pure magnesium bi-crystal. The deformation mechanisms considering in the present analysis method are basal slip <a>, prismatic slip <a>, 1st order pyramidal slip <a>, 2nd order pyramidal slip <a+c> and tensile twinning <a+c>. Tensile twinning is incorporated into crystal plasticity analysis assuming that twinning plane and direction of shear by twinning are equivalent to slip plane and slip direction, respectively. Critical resolved shear stresses (CRSSs) for each slip system in the literatures were used. Analysis model is designed to investigate the influence of grain boundary on the activation of slip systems. That is, one grain consisting of bi-crystal (grain A) had the crystal orientation whose Schmid factor for prismatic slip is 0.5. The crystal orientation of the other grain (grain B) was slightly deviated from that of grain A. The result of the calculation of tensile loading of the bi-crystal showed that both grains are deformed by the multiple slip of basal slip system, which resulted in the formation of GN dislocation bands.

scholarly journals Quantitative study of the effect of grain boundary parameters on the slip system level Hall-Petch slope for basal slip system in Mg-4Al

2020 ◽  
Vol 200 ◽  
pp. 148-161 ◽  
Author(s):  
Mohsen Taheri Andani ◽  
Aaditya Lakshmanan ◽  
Veera Sundararaghavan ◽  
John Allison ◽  
Amit Misra
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Quantitative Study ◽  
Basal Slip ◽  
System Level

The Slip Transfer Process Through Grain Boundaries in HCP Ti

1993 ◽  
Vol 319 ◽  
Author(s):  
J. Shirokoff ◽  
I.M. Robertson ◽  
H.K. Birnbaum
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Grain Boundaries ◽  
Slip Systems ◽  
Boundary Dislocation ◽  
Burgers Vector ◽  
Slip Transfer ◽  
Transmission Electron ◽  
Fcc Materials

AbstractInformation on the mechanisms of slip transfer across grain boundaries in an HCP α-Ti alloy has been obtained from deformation experiments performed In situ in the transmission electron microscope. Initially, lattice dislocations are accommodated within the grain boundary until a critical local dislocation density is reached. The boundary then responds by activating slip in the adjoining grain on the slip system experiencing the highest local resolved shear stress and producing the residual grain-boundary dislocation with the smallest Burgers vector. Slip on secondary slip systems may be initiated provided they reduce the magnitude of the Burgers vector of, or eliminate, the residual grainboundary dislocation. The selection rules used to predict the slip system activated by the grain boundary are the same as apply in ordered and disordered FCC materials.

The Effect of Grain Boundary Chemistry on the Slip Transmission Process Through Grain Boundaries in Ni3Al

1991 ◽  
Vol 238 ◽  
Author(s):  
I. M. Robertson ◽  
T. C. Lee ◽  
Raja Subramanian ◽  
H. K. Birnbaum
Keyword(s):  
Stress Concentration ◽  
Grain Boundary ◽  
Slip System ◽  
Grain Boundaries ◽  
Local Stress ◽  
Crack Advance ◽  
Boron Doped ◽  
Show Evidence ◽  
Fcc Alloy ◽  
Boundary Chemistry

ABSTRACTThe conditions established in disordered FCC systems for predicting the slip system that will be activated by a grain boundary to relieve a local stress concentration have been applied to the ordered FCC alloy Ni3Al. The slip transfer behavior in hypo-stoichiometric Ni3Al with (0.2 at. %B) and without boron was directly observed by performing the deformation experiments in situ in the transmission electron microscope. In the boron-free and boron-doped alloys, lattice dislocations were incorporated in the grain boundary, but did not show evidence of dissociation to grain boundary dislocations or of movement in the grain boundary plane. The stress concentration associated with the dislocation pileup at the grain boundary was relieved by the emission of dislocations from the grain boundary in the boron-doped alloy. The slip system initiated in the adjoining grain obeyed the conditions established for disordered FCC systems. In the boron-free alloy, the primary stress relief mechanism was grain-boundary cracking, although dislocation emission from the grain boundary also occurred and accompanied intergranular crack advance. Because of the importance of the grain boundary chemistry in the models for explaining the boron-induced ductility in hypo-stoichiometric Ni3Al, the chemistry of grain boundaries in well-annealed boron-doped and boron-free alloys was determined by using EDS. No Ni enrichment was found at the grain boundaries examined. These observations are discussed in terms of the different models proposed to explain the ductility improvement in the boron-doped, hypo-stoichiometric alloy.

Interaction of Slip Bands with Grain Boundary - in situ TEM Observation

2000 ◽  
Vol 652 ◽  
Author(s):  
Juliana Gemperlová ◽  
Alain Jacques ◽  
Antonín Gemperle ◽  
Niva Zárubová
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
The Other ◽  
In Situ Tem ◽  
Post Mortem ◽  
Secondary Slip ◽  
Slip Bands ◽  
Transmission Electron ◽  
Primary Slip System

ABSTRACTMechanism of the slip transmission across the grain boundaries was studied on Σ3 bicrystals of Fe-4at%Si by transmission electron microscopy. In situ straining experiments as well as post mortem observations were performed. Three distinct events were observed in dependence on the angle α between the slip and grain boundary planes, namely transformation of the tertiary slip system in one grain into the secondary slip system in the other grain for α ≍ 90°, cross slip of dislocations of the primary slip system into the {112} plane parallel to the grain boundary for α ≍21°, and an abrupt formation of a sub-grain boundary in one grain for α ≍49°. Reasons for these diverse phenomena will be discussed in terms of interactions between the slip dislocations and the grain boundary dislocations.

scholarly journals Crystallographic Orientation Dependence of Mechanical Responses of FeCrAl Micropillars

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 943
Author(s):  
Dongyue Xie ◽  
Binqiang Wei ◽  
Wenqian Wu ◽  
Jian Wang
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Single Crystal ◽  
Room Temperature ◽  
Orientation Dependence ◽  
Slip Systems ◽  
Flow Strength ◽  
Mechanical Responses ◽  
Fecral Alloy ◽  
Strain Hardening Rate

Iron-chromium-aluminum (FeCrAl) alloys are used in automobile exhaust gas purifying systems and nuclear reactors due to its superior high-temperature oxidation and excellent corrosion resistance. Single-phase FeCrAl alloys with a body centered cubic structure plastically deform through dislocation slips at room temperature. Here, we investigated the orientation dependence of mechanical responses of FeCrAl alloy through testing single-crystal and bi-crystal micropillars in a scanning electron microscopy at room temperature. Single-crystal micropillars were fabricated with specific orientations which favor the activity of single slip system or two slip systems or multiple slip systems. The strain hardening rate and flow strength increase with increasing the number of activated slip system in micropillars. Bi-crystal micropillars with respect to the continuity of slip systems across grain boundary were fabricated to study the effect of grain boundary on slip transmission. The high geometrical compatibility factor corresponds to a high flow strength and strain hardening rate. Experimental results provide insight into understanding mechanical response of FeCrAl alloy and developing the mechanisms-based constitutive laws for FeCrAl polycrystalline aggregates.

Clarification of Extremely High R-Value Mechanism of the Electro-Deposited Pure Iron

2014 ◽  
Vol 922 ◽  
pp. 740-743 ◽  
Author(s):  
Natsuko Sugiura ◽  
Naoki Yoshinaga
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Slip Plane ◽  
Pure Iron ◽  
Tensile Deformation ◽  
Fiber Texture ◽  
Active Slip System ◽  
Sheet Surface ◽  
R Value ◽  
Active Slip

Electro-deposited pure iron has a very sharp and isotropic <111>//ND fiber texture and a needle shaped grain elongated in the ND. This pure iron exhibits an r-value of over 7, and it is difficult to explain such a high r-value only from the texture. Specific {110} plane slips, which are perpendicular to the sheet surface, exclusively act in this material and this limitation of the active slip system is the main mechanism behind the extraordinarily high r-value. Thus, tensile deformation by this slip system doesn’t require a decrease in thickness. In this study, the mechanism of this slip system limitation is investigated. Because both the {110} slip plane and grain boundary are perpendicular to the sheet surface, the slip plane can easily connect with adjacent grains. This good continuity of slip plane with adjacent grain may have an influence on the choice of slip system.

Sign in / Sign up

Export Citation Format

Share Document