scholarly journals Anisotropic Plastic Behavior in an Extruded Long-Period Ordered Structure Mg90Y6.5Ni3.5 (at.%) Alloy

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 279
Author(s):  
Gerardo Garces ◽  
Rafael Barea ◽  
Andreas Stark ◽  
Norbert Schell
Keyword(s):  
Basal Plane ◽  
Extrusion Direction ◽  
Plastic Behavior ◽  
Ordered Structure ◽  
Lpso Phase ◽  
Long Period ◽  
Anisotropic Plastic ◽  
The Difference ◽  
Internal Strains

The Mg90Y6.5Ni3.5 alloy composed almost completely of the Long-Period-Stacking-Ordered (LPSO) phase has been prepared by casting and extrusion at high temperature. An elongated microstructure is obtained where the LPSO phase with 18R crystal structure is oriented with its basal plane parallel to the extrusion direction. Islands of α-magnesium are located between the LPSO grains. The mechanical properties of the alloy are highly anisotropic and depend on the stress sign as well as the relative orientation between the stress and the extrusion axes. The alloy is stronger when it is compressed along the extrusion direction. Under this configuration, the slip of <a> dislocations in the basal plane is highly limited. However, the activation of kinking induces an increase in the plastic deformation. In the transversal extrusion direction, some grains deform by the activation of basal slip. The difference in the yield stress between the different stress configurations decreases with the increase in the test temperature. The evolution of internal strains obtained during in-situ compressive experiments reveals that tensile twinning is not activated in the LPSO phase.

Compression of Micro-pillars of a Long Period Stacking Ordered Phase in the Mg-Zn-Y system

2013 ◽  
Vol 1516 ◽  
pp. 151-156 ◽  
Author(s):  
Atsushi Inoue ◽  
Kyosuke Kishida ◽  
Haruyuki Inui ◽  
Koji Hagihara
Keyword(s):  
Basal Plane ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Deformation Bands ◽  
Axis Orientation ◽  
Lpso Phase ◽  
Long Period ◽  
Image Position ◽  
Micro Pillars ◽  
Loading Axis

ABSTRACTDeformation behavior of an 18R-type long period stacking ordered (LPSO) phase in the Mg-Zn-Y system was studied by micro-pillar compressions of single crystalline specimens prepared by focused ion beam (FIB) technique as a function of loading axis orientation and specimen dimensions. When the loading axis is inclined to the basal plane of the LPSO phase by 42°, basal slip of (0001)<11$\bar 2$0>-type is activated irrespective of the specimen dimensions. When the loading axis is parallel to the basal plane, the formation of thick deformation bands are observed for all specimens tested. Strong size-dependence of yield stress values is observed for both types of micro-pillar specimens with different loading axis orientations.

Crystal Structures of Long-Period Stacking-Ordered Phases in the Mg-TM-RE Ternary Systems

2013 ◽  
Vol 1516 ◽  
pp. 291-302 ◽  
Author(s):  
Kyosuke Kishida ◽  
Hideyuki Yokobayashi ◽  
Atsushi Inoue ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structures ◽  
Hexagonal Lattice ◽  
Ternary Systems ◽  
Dark Field ◽  
Lattice Points ◽  
Atomic Arrangement ◽  
Lpso Phase ◽  
Long Period ◽  
The Difference ◽  
Image Position

ABSTRACTCrystal structures of long-period stacking-ordered (LPSO) phases in the Mg-TM (transition-metal)-RE(rare-earth) systems were investigated by atomic resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The 18R-type LPSO phase is constructed by stacking 6-layer structural blocks, each of which contains four consecutive close-packed planes enriched with TM and RE atoms. Formation of the TM6RE8 clusters with the L12 type atomic arrangement is commonly observed in both Mg-Al-Gd and Mg-Zn-Y LPSO phases. The difference between the crystal structures of Mg-Al-Gd and Mg-Zn-Y LPSO phases can be interpreted as the difference in the in-plane ordering of the TM6RE8 clusters in the structural block. The Mg-Al-Gd LPSO phase exhibits a long-range in-plane ordering of Gd and Al, which can be described by the periodic arrangement of the Al6Gd8 clusters with the L12 type atomic arrangement on lattice points of a two-dimensional 2$\sqrt 3 $aMg × 2$\sqrt 3 $aMg primitive hexagonal lattice, although the LPSO phase in the Zn/Y-poor Mg-Zn-Y alloys exhibits a shortrange in-plane ordering of the Zn6Y8 clusters.

Multimodal Microstructure Evolution in Wrought Mg-Zn-Y Alloys with High Strength and Increased Ductility

2010 ◽  
Vol 654-656 ◽  
pp. 615-618 ◽  
Author(s):  
Michiaki Yamasaki ◽  
Kenji Hashimoto ◽  
Koji Hagihara ◽  
Yoshihito Kawamura
Keyword(s):  
Microstructure Evolution ◽  
Extrusion Direction ◽  
High Strength ◽  
Phase Region ◽  
Deformation Bands ◽  
Cast State ◽  
Lpso Phase ◽  
Long Period ◽  
Effective Dispersion ◽  
Coarse Grains

High strength and ductile Mg96Zn2Y2 (at%) alloys with multi-modal microstructure are developed. Microstructure of the extruded Mg96Zn2Y2 alloy consists of three regions; the dynamically recrystallized -Mg fine-grains region, the hot-worked -Mg coarse-grains region elongated along extrusion direction, and the long-period stacking ordered (LPSO) phase region with kink deformation bands. Bimodal microstructure evolution in -Mg matrix is influenced by the morphology of the LPSO phase in the as-cast state, therefore, the effect of secondary dendrite arm spacing in cast state on the microstructure evolution and mechanical properties of the extruded Mg-Zn-Y alloy is investigated. An increase in the dynamically recrystallized grains improves ductility of the extruded alloys; the effective dispersion of the LPSO phase enhances strengthening of the alloy.

Microstructure Evolution during Lithiation and Delithiation of Ni3Sn2 Anode for Lithium Secondary Batteries

2007 ◽  
Vol 26-28 ◽  
pp. 225-228 ◽  
Author(s):  
Takashi Kosho ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Microstructure Evolution ◽  
Basal Plane ◽  
Crystal Orientation ◽  
Ordered Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lithium Secondary Batteries ◽  
Transmission Electron ◽  
The Difference ◽  
Discharge Capacities

Electrochemical properties and microstructure evolution during lithiation and delithiation of Ni3Sn2 single crystals with the hexagonal B82-type related ordered structure have been studied as a function of the crystal orientation by charge/discharge tests, powder X-ray diffraction and transmission electron microscopy. Charge and discharge capacities are strongly dependent on the crystal orientation. When the surface of the thin plate anode is perpendicular to the basal plane of the parent B82 unit cell, the capacities are approximately twice as high as those for the sample whose surface is parallel to the basal plane, which is considered to be related to the difference in the diffusion behavior of lithium with respect to the crystal orientation.

Characterization of the Acoustic Emission Response and Mechanical Properties of Mg Alloy with LPSO Phase

2016 ◽  
Vol 879 ◽  
pp. 762-766 ◽  
Author(s):  
Klaudia Horváth ◽  
Daria Drozdenko ◽  
Gerardo Garcés ◽  
Patrik Dobron ◽  
Kristián Máthis
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Extrusion Direction ◽  
Constant Strain Rate ◽  
Lpso Phase ◽  
Long Period ◽  
Deformation Tests

Mechanical properties of extruded WZ72 magnesium alloy with long-period stacking ordered (LPSO) phase were investigated during compression loading at room temperature and at a constant strain rate of 10-3 s-1. The samples of (8 x 4 x 4) mm3 were compressed along three directions with respect to the lamellar LPSO-phase: parallel (ED), perpendicular (TD) and under 45°. Concurrently with the deformation tests, the acoustic emission (AE) response of the specimens was recorded. The AE measurements revealed that both the twinning activity and the kinking of the LPSO phase significantly depend on the orientation of LPSO phase. The highest strength was observed for the sample which was compressed parallel to the LPSO phase (extrusion direction). The highest AE activity was also measured in this sample.

Deformation Behavior of Mg-Ni-Y Alloy with Long Period Stacking Ordered Phase

2012 ◽  
Vol 706-709 ◽  
pp. 1176-1180 ◽  
Author(s):  
Takaomi Itoi ◽  
Ryu Ichikawa ◽  
Mitsuji Hirohashi
Keyword(s):  
Compression Test ◽  
Basal Plane ◽  
Room Temperature ◽  
Fracture Strain ◽  
Alloy Sheet ◽  
Lpso Phase ◽  
Long Period ◽  
Lpso Structure ◽  
Plane Sheet ◽  
Plate Type

Microstructures of the long period stacking ordered (LPSO) phase deformed by compression test or rolling at room temperature were investigated. The Mg85Ni6Y9 (at.%) alloy was composed mostly of plate-type phase with 10H-type LPSO structure. The Mg85Ni6Y9 alloy exhibited compression yield stress of 365 MPa and fracture strain of 30 % at room temperature. After compression test with applied stress of 25 %, a bend, delamination between basal planes and crack initiation at boundary of the LPSO phase were observed. From these microstructural features, it was considered that the deformation of the LPSO phase significantly influenced by a kink deformation. The Mg85Ni6Y9 alloy could be rolled with 30 % reduction at room temperature. The kink deformation was frequently observed in the LPSO phase of the alloy sheet. The basal plane texture was formed in plane sheet of the alloy sheet. However, it was more difficult to form basal plane texture in the LPSO phase than in the pure-Mg due to introduce the kink deformation. Therefore, it was considered that better rollability of the Mg85Ni6Y9 alloy compared with the pure-Mg was brought for the kink deformation.

Comparison of Mammography and Ultrasonography for Tumor Size of DCIS of Breast Cancer

2019 ◽  
Vol 15 (2) ◽  
pp. 209-213
Author(s):  
Yu Wang ◽  
Jiantao Wang ◽  
Haiping Wang ◽  
Xinyu Yang ◽  
Liming Chang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Correlation Coefficient ◽  
Tumor Size ◽  
Ductal Carcinoma ◽  
Pearson Correlation ◽  
Dense Breast ◽  
Pathological Examination ◽  
Negative Group ◽  
The Difference

Objective: Accurate assessment of breast tumor size preoperatively is important for the initial decision-making in surgical approach. Therefore, we aimed to compare efficacy of mammography and ultrasonography in ductal carcinoma in situ (DCIS) of breast cancer. Methods: Preoperative mammography and ultrasonography were performed on 104 women with DCIS of breast cancer. We compared the accuracy of each of the imaging modalities with pathological size by Pearson correlation. For each modality, it was considered concordant if the difference between imaging assessment and pathological measurement is less than 0.5cm. Results: At pathological examination tumor size ranged from 0.4cm to 7.2cm in largest diameter. For mammographically determined size versus pathological size, correlation coefficient of r was 0.786 and for ultrasonography it was 0.651. Grouped by breast composition, in almost entirely fatty and scattered areas of fibroglandular dense breast, correlation coefficient of r was 0.790 for mammography and 0.678 for ultrasonography; in heterogeneously dense and extremely dense breast, correlation coefficient of r was 0.770 for mammography and 0.548 for ultrasonography. In microcalcification positive group, coeffient of r was 0.772 for mammography and 0.570 for ultrasonography. In microcalcification negative group, coeffient of r was 0.806 for mammography and 0.783 for ultrasonography. Conclusion: Mammography was more accurate than ultrasonography in measuring the largest cancer diameter in DCIS of breast cancer. The correlation coefficient improved in the group of almost entirely fatty/ scattered areas of fibroglandular dense breast or in microcalcification negative group.

scholarly journals A Study on the Damping Capacities of Mg–Zn–Y-Based Alloys with Lamellar Long Period Stacking Ordered Phases by Preparation Process

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 79
Author(s):  
Ruopeng Lu ◽  
Kai Jiao ◽  
Yuhong Zhao ◽  
Kun Li ◽  
Keyu Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Damping Capacity ◽  
Second Phase ◽  
Preparation Process ◽  
Obvious Effect ◽  
Lpso Phase ◽  
Long Period ◽  
Lamellar Phases ◽  
Ordered Phases

Mg alloys with fine mechanical properties and high damping capacities are essential in engineering applications. In this work, Mg–Zn–Y based alloys with lamellar long period stacking ordered (LPSO) phases were obtained by different processes. The results show that a more lamellar second phase can be obtained in the samples with more solid solution atoms. The density of the lamellar LPSO phase has an obvious effect on the damping of the magnesium alloy. The compact LPSO phase is not conducive to dislocation damping, but sparse lamellar phases can improve the damping capacity without significantly reducing the mechanical properties. The Mg95.3Zn2Y2.7 alloy with lamellar LPSO phases and ~100 μm grain size exhibited a fine damping property of 0.110 at ε = 10–3.

scholarly journals Comparison of In-Situ and Retrospective Self-Reports on Assessing Hearing Aid Outcomes

2020 ◽  
Author(s):  
Yu-Hsiang Wu ◽  
Elizabeth Stangl ◽  
Octav Chipara ◽  
Anna Gudjonsdottir ◽  
Jacob Oleson ◽  
...  
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
Outcome Data ◽  
Self Report ◽  
Data Collection And Analysis ◽  
Self Reports ◽  
Outcome Difference ◽  
The Difference ◽  
Ecological Momentary

Abstract Background Ecological momentary assessment (EMA) is a methodology involving repeated surveys to collect in-situ self-reports that describe respondents' current or recent experiences. Audiology literature comparing in-situ and retrospective self-reports is scarce. Purpose To compare the sensitivity of in-situ and retrospective self-reports in detecting the outcome difference between hearing aid technologies, and to determine the association between in-situ and retrospective self-reports. Research Design An observational study. Study Sample Thirty-nine older adults with hearing loss. Data Collection and Analysis The study was part of a larger clinical trial that compared the outcomes of a prototype hearing aid (denoted as HA1) and a commercially available device (HA2). In each trial condition, participants wore hearing aids for 4 weeks. Outcomes were measured using EMA and retrospective questionnaires. To ensure that the outcome data could be directly compared, the Glasgow Hearing Aid Benefit Profile was administered as an in-situ self-report (denoted as EMA-GHABP) and as a retrospective questionnaire (retro-GHABP). Linear mixed models were used to determine if the EMA- and retro-GHABP could detect the outcome difference between HA1 and HA2. Correlation analyses were used to examine the association between EMA- and retro-GHABP. Results For the EMA-GHABP, HA2 had significantly higher (better) scores than HA1 in the GHABP subscales of benefit, residual disability, and satisfaction (p = 0.029–0.0015). In contrast, the difference in the retro-GHABP score between HA1 and HA2 was significant only in the satisfaction subscale (p = 0.0004). The correlations between the EMA- and retro-GHABP were significant in all subscales (p = 0.0004 to <0.0001). The strength of the association ranged from weak to moderate (r = 0.28–0.58). Finally, the exit interview indicated that 29 participants (74.4%) preferred HA2 over HA1. Conclusion The study suggests that in-situ self-reports collected using EMA could have a higher sensitivity than retrospective questionnaires. Therefore, EMA is worth considering in clinical trials that aim to compare the outcomes of different hearing aid technologies. The weak to moderate association between in-situ and retrospective self-reports suggests that these two types of measures assess different aspects of hearing aid outcomes.

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