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Investigation of Migration and Transformation of Self-Interstitial Atoms in 3C-SiC via DFT Calculations 用DFT计算研究3C-SiC中自间隙原子的迁移和转变
AMI: Scripta Materialia Pub Date : 2021-01-26 DOI: 10.2139/ssrn.3770989
Shangquan Zhao, G. Ran, Fei Gao, S. Ma
{"title":"Investigation of Migration and Transformation of Self-Interstitial Atoms in 3C-SiC via DFT Calculations","authors":"Shangquan Zhao, G. Ran, Fei Gao, S. Ma","doi":"10.2139/ssrn.3770989","DOIUrl":"https://doi.org/10.2139/ssrn.3770989","url":null,"abstract":"First-principles calculations were carried out to investigate the stable and potential metastable structure of self-interstitial atoms (SIAs) in 3C-SiC. The most stable C and Si interstitials we obtained are Ci-C and Sii-Si split interstitials, respectively. In addition, a serious of metastable structures Ci-C (x = 0.63 ~ 0.81), Ci-C , Ci-Si , Sii-Si and Sii-Si have been observed. The migration and transformation of these SIAs were systematically studied. The minimum migration barrier for the full space rotation of C and Si interstitial are 0.49 eV and 0.73 eV, respectively. For the long-distance migration of SIAs, the minimum migration energy for C and Si interstitials is 0.71 eV and 0.73 eV, the corresponding migration paths are Ci-C(2 ‾5‾ 2) ↔ Ci-Si(1 1 6) ↔ Ci-C(‾5‾ 2 2), and Sii-Si ↔ SiTC ↔ Sii-Si .","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79707011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Novel Ti–20zr–49.7pd High Temperature Shape Memory Alloy with Facilitated Detwinning and Precipitation Strengthening 新型Ti-20zr-49.7pd高温形状记忆合金，易孪晶和析出强化
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3947687
H. Tobe, Shunsuke Kojima, E. Sato
{"title":"Novel Ti–20zr–49.7pd High Temperature Shape Memory Alloy with Facilitated Detwinning and Precipitation Strengthening","authors":"H. Tobe, Shunsuke Kojima, E. Sato","doi":"10.2139/ssrn.3947687","DOIUrl":"https://doi.org/10.2139/ssrn.3947687","url":null,"abstract":"It is desirable to develop high temperature shape memory alloys with a martensitic transformation start temperature (Ms) above 100°C and a recoverable strain of about 4‐6% in the shape memory effect. The latter property is achieved with low variant reorientation stress due to easy detwinning of martensite and high plastic deformation stress due to precipitation strengthening. We have previously demonstrated the facilitation of detwinning for Ti–Zr–Ni–Pd quaternary alloy systems through controlling the crystal structure of martensite, and proposed that Ti–(15‐20)Zr–49.7Pd (at.%) and surrounding Ni‐containing compositions are candidates. In this study, aging temperature was optimized for a Ti–20Zr–49.7Pd alloy, and an excellent shape memory effect with Ms above 130°C, low reorientation stress around 200 MPa, high plastic deformation stress around 1800 MPa, and large recovery strain of 4.5% was achieved. On the other hand, short‐range ordering of solute atoms occurs just above the reverse transformation temperature and decreases Ms.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"189 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77386941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Interpreting Dynamic Hardness: Separating Roles of Speed, Strain Rate and Shock 解释动态硬度:分离速度、应变率和冲击的作用
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3931597
Y. Mao, B. Barnett, K. Prasad, A. Vivek, G. Daehn
{"title":"Interpreting Dynamic Hardness: Separating Roles of Speed, Strain Rate and Shock","authors":"Y. Mao, B. Barnett, K. Prasad, A. Vivek, G. Daehn","doi":"10.2139/ssrn.3931597","DOIUrl":"https://doi.org/10.2139/ssrn.3931597","url":null,"abstract":"Mechanical hardness is classically defined as force divided by indented area. Hardness (dynamic) is alternately sometimes defined based on indentation energy absorbed normalized by displaced volume. This elementary study compares static and dynamic hardness using standard definitions. Hardness is often observed to increase with strain rate and this is commonly interpreted as strain-rate hardening by mechanisms such as dislocation drag. This analysis considers the simplest situation – ballistic indentation of an elastic-perfectly plastic material without rate dependence. Results from both Coupled Eulerian-Lagrangian (CEL) and Smoothed Particle Hydrodynamics (SPH) show a linear correlation between indenter impact speed and dynamic hardness. Extrapolating to an impact speed of 0 m/s converges to static hardness. Neither approach demonstrates indenter size dependence. High impact speeds also can introduce shock. It is suggested that speed and shock hardening effects can account for the increase in dynamic hardness with increased indenter speed without strain-rate-hardening.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79974071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Unveiling Solidification Mode Transition and Crystallographic Characteristics in Laser 3D-Printed Al 2O 3-ZrO 2 Eutectic Ceramics 揭示激光3d打印al2o3 - zro - 2共晶陶瓷的凝固模式转变和晶体学特征
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3939456
Z. Fan, Yu Yin, Qiyang Tan, Xuliang Li, P. Niu, Rui-di Li, Tiechui Yuan, Mingxing Zhang, Han Huang
{"title":"Unveiling Solidification Mode Transition and Crystallographic Characteristics in Laser 3D-Printed Al 2O 3-ZrO 2 Eutectic Ceramics","authors":"Z. Fan, Yu Yin, Qiyang Tan, Xuliang Li, P. Niu, Rui-di Li, Tiechui Yuan, Mingxing Zhang, Han Huang","doi":"10.2139/ssrn.3939456","DOIUrl":"https://doi.org/10.2139/ssrn.3939456","url":null,"abstract":"The crystallographic texture distribution in 3D-printed Al2O3-ZrO2 eutectics was found completely different from those prepared by directional solidification. The as-fabricated specimen was mainly composed of randomly oriented eutectic colonies, as a result of the initial uncoupled growth at molten pool boundaries. Specifically, the free-grown Al2O3 faceted particulates in the uncoupled region acted as effective nucleation sites that triggered coupled eutectic renucleation and growth. Except for some misoriented ZrO2 precipitates in Al2O3 matrix, well-defined multiple crystallographic orientation relationships existed between eutectic phases in the colony, e.g. {0001}Al2O3 ∥ {100}ZrO2 and {1120}Al2O3∥ {100}ZrO2. The lattice matching change was attributed to the varied solidification conditions along the solid/liquid interface, as predicted by Jackson-Hunt model.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90757677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Role of a Shear Planar Mesodefect in Nucleation of Crack at Grains Junction Due to Athermal Grain Boundary Sliding 剪切平面细观缺陷在晶界非热滑动晶界裂纹成核中的作用
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3885130
V. Perevezentsev, S. Kirikov, J. Svirina
{"title":"Role of a Shear Planar Mesodefect in Nucleation of Crack at Grains Junction Due to Athermal Grain Boundary Sliding","authors":"V. Perevezentsev, S. Kirikov, J. Svirina","doi":"10.2139/ssrn.3885130","DOIUrl":"https://doi.org/10.2139/ssrn.3885130","url":null,"abstract":"We consider the conditions for microcrack nucleation in a grain junction due to athermal sliding along the grain boundary, containing a strain-induced shear-type planar mesodefect. The dependences of critical external stress of microcrack nucleation on the mesodefect length, its strength and the threshold stress of athermal sliding are obtained. It is shown that the presence of the mesodefect at the grain boundary can lead to a significant decrease of the crack nucleation stress in comparison with the case of pure grain boundary sliding. It is concluded that the induced athermal grain boundary sliding, carried out by the motion of the glissile components of dislocations, accumulating at the grain boundaries during intragranular plastic deformation, can be considered as one of the possible mechanisms for microcracks nucleation in materials with fragmented structure.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"s3-39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90829050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
In Situ Growth of a Novel Nanoscaled Rock Salt Titanium Zirconium Nitride Phase in a Silicon Nitride Matrix 新型纳米岩盐氮化钛锆相在氮化硅基体中的原位生长
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3920960
M. Bechelany, Abhijeet Lale, Maxime Balestrat, C. Gervais, S. Malo, R. Nishihora, S. Bernard
{"title":"In Situ Growth of a Novel Nanoscaled Rock Salt Titanium Zirconium Nitride Phase in a Silicon Nitride Matrix","authors":"M. Bechelany, Abhijeet Lale, Maxime Balestrat, C. Gervais, S. Malo, R. Nishihora, S. Bernard","doi":"10.2139/ssrn.3920960","DOIUrl":"https://doi.org/10.2139/ssrn.3920960","url":null,"abstract":"The first demonstration of a nanoscaled titanium zirconium nitride (TiZrN2) single-phase isolated during the formation of precursor-derived silicon nitride (Si3N4) matrix nanocomposites is highlighted in the present paper. We employed polymethylsilazane (PMSZ) as a Si3N4 precursor, which was chemically modified with Zr[N(CH2CH3)2]4 and Ti[N(CH3)2]4, ammonolyzed and pyrolyzed under ammonia (1000 °C) then annealed in flowing nitrogen (1500 °C). The TiZrN2 phase grew in the temperature range 1000-1500 °C and was isolated - because of its confinement into a Si3N4matrix - as a nanoscaled rock salt structure after annealing at 1500 °C as shown by X-ray diffraction. HRTEM investigations confirmed the unique nanostructural feature of the nanocomposites made of TiZrN2 nanocrystals with a size as low as 9 nm distributed in a- and b-Si3N4 phases.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79986127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Near-White Light and Near-Infrared Luminescence in Perovskite Ga:LaCrO 3 钙钛矿Ga:LaCrO 3的近白光和近红外发光
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3918915
T. Rajalekshmi, V. Mishra, Tejendra Dixit, M. Miryala, M. S. Ramachandra Rao, K. Sethupathi
{"title":"Near-White Light and Near-Infrared Luminescence in Perovskite Ga:LaCrO 3","authors":"T. Rajalekshmi, V. Mishra, Tejendra Dixit, M. Miryala, M. S. Ramachandra Rao, K. Sethupathi","doi":"10.2139/ssrn.3918915","DOIUrl":"https://doi.org/10.2139/ssrn.3918915","url":null,"abstract":"We report the realization of near-white light emission (near-WLE) and the selective tuning to the near-infrared (NIR) luminescence from Ga substituted lanthanum chromite perovskite with electron-beam excitation. The Ga3+ acts as an electron donor in the LaCrO3 system and the emission intensity increases with Ga substitution. The near-WLE in CL, arises from the combination of 4T1(F)→4A2 (blue), 4T1(P)→4A2 (green) and 4T2→4A2 (red) spin allowed transitions and 2E→4A2 spin forbidden transitions from the Cr3+ ion. The spin allowed transitions from the Cr3+ ions are not common, however can be accomplished by adjusting the Cr3+/Ga3+ ion concentration in the host lattice. The NIR emission originates from the selective 2E→4A2 transition, which dominates with the increasing concentration of Ga3+ ions. The Density Functional Theory (DFT) calculations point out the presence of extra electronic states with Ga substitution, which validates the observation of NIR emission in Ga substituted samples.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83489949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Large Energy Storage Density and Electrocaloric Strength of Pb 0.97La 0.02(Zr 0.46-xSn 0.54Ti x)O 3 Antiferroelectric Thick Film Ceramics Pb 0.97La 0.02(Zr 0.46-xSn 0.54Ti x) o3反铁电厚膜陶瓷的大储能密度和电强度
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3910607
Shibin Wang, Pengfei Zhao, Xiaodong Jian, Yingbang Yao, T. Tao, B. Liang, Shengguo Lu
{"title":"Large Energy Storage Density and Electrocaloric Strength of Pb 0.97La 0.02(Zr 0.46-xSn 0.54Ti x)O 3 Antiferroelectric Thick Film Ceramics","authors":"Shibin Wang, Pengfei Zhao, Xiaodong Jian, Yingbang Yao, T. Tao, B. Liang, Shengguo Lu","doi":"10.2139/ssrn.3910607","DOIUrl":"https://doi.org/10.2139/ssrn.3910607","url":null,"abstract":"Pb0.97La0.02(Zr0.46-xSn0.54Tix)O3 (PLZST, x=0.04, 0.06, 0.08, 0.15, and 0.18) antiferroelectric thick film ceramics were fabricated via a tape-casting approach. The energy storage performance and electrocaloric effect were investigated in terms of the measurements on the hysteresis loops and Maxwell relation. The maximum value of energy storage density of 5.2 J/cm3 and efficiency of 78.2 % were procured at 600 kV/cm in Pb0.97La0.02(Zr0.42-xSn0.54Ti0.04)O3 thick film ceramics at room temperature. In addition, the ECE was indirectly calculated using the Maxwell relation and the P-E loops as a function of temperature and electric field, a reversible adiabatic temperature change of ΔT=2.47 °C was presented in Pb0.97La0.02(Zr0.42-xSn0.54Ti0.04)O3 thick film ceramics at 500 kV/cm, corresponding to the calculated electrocaloric strength of 0.48 K(MV/m)-1. These results indicate that the PLZST thick film ceramics are promising for practical applications in high-power energy storage capacitors and solid-state refrigeration devices.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87550632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
In-situ Observation of Migration of {10¯12} α Twinning in an Mg-5Gd-3.5Ga (at.%) As-Cast Alloy Mg-5Gd-3.5Ga (at.%)铸态合金{10¯12}α孪晶迁移的原位观察
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3880066
Kaixuan Li, Yuanlin Zhuang, Ligong Zhao, Dongshan Zhao, He Zheng, Shuangfeng Jia, Ying Zhang, Peili Zhao, J. Gui, Jianbo Wang
{"title":"In-situ Observation of Migration of {10¯12} α Twinning in an Mg-5Gd-3.5Ga (at.%) As-Cast Alloy","authors":"Kaixuan Li, Yuanlin Zhuang, Ligong Zhao, Dongshan Zhao, He Zheng, Shuangfeng Jia, Ying Zhang, Peili Zhao, J. Gui, Jianbo Wang","doi":"10.2139/ssrn.3880066","DOIUrl":"https://doi.org/10.2139/ssrn.3880066","url":null,"abstract":"We have achieved direct observation of the interaction between {10¯12}<sub>α </sub> twinning and long period stacking ordered (LPSO) structures in an Mg-5Gd-3.5Ga (at.%) as-cast alloy through in-situ compression experiments of submicron-sized pillars, and found that thick LPSO plates effectively retard the twinning propagation in the direction of perpendicular to the LPSO basal plane. In addition, although twinning can easily pass through low-density stacking faults (SFs), the step of twin boundaries on both sides of SFs on the atomic scale also exhibits resistance of SFs to twins. Dense LPSO structures hinder the occurrence of plastic deformation caused by twinning deformation. In this study, an in-situ technique was used to further discuss the strengthening mechanism of LPSO structures.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80408609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Comparison of in- and ex-situ Shear Bands in Metallic Glass by Transmission Electron Microscopy 金属玻璃原位剪切带与非原位剪切带的透射电镜比较
AMI: Scripta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3880065
H. Rösner, C. Kübel, S. Ostendorp, G. Wilde
{"title":"A Comparison of in- and ex-situ Shear Bands in Metallic Glass by Transmission Electron Microscopy","authors":"H. Rösner, C. Kübel, S. Ostendorp, G. Wilde","doi":"10.2139/ssrn.3880065","DOIUrl":"https://doi.org/10.2139/ssrn.3880065","url":null,"abstract":"Plastic deformation of metallic glasses performed at temperatures well below the glass transition proceeds via the formation of shear bands. In this contribution shear bands originating from in situ tensile tests of Al88Y7Fe5 melt-spun ribbons conducted in a transmission electron microscope are compared with ones which had formed ex situ during cold rolling. The observed contrasts for shear bands generated in situ at the edges of thin electron-transparent foils are shown to be related to a meniscus-like foil thickness reduction. In comparison with ex situ samples, alternating contrast changes due to volume changes are missing and the shear band width is a factor of 15 larger. The meniscus-like shear band profile is accounted for by the thin foil allowing volume increase due to shear deformation to annihilate via the free surfaces of the thin foil and the sheared zones to widen.","PeriodicalId":7765,"journal":{"name":"AMI: Scripta Materialia","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81942416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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