Consideration of Orowan strengthening effect in particulate-reinforced metal matrix nanocomposites: A model for predicting their yield strength - Peeref (2024)

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Article Materials Science, Multidisciplinary

Enhanced strengthening and hardening via self-stabilized dislocation network in additively manufactured metals

Zan Li, Yinan Cui, Wentao Yan, Di Zhang, Yan Fang, Yujie Chen, Qian Yu, Ge Wang, Heng Ouyang, Chen Fan, Qiang Guo, Ding -Bang Xiong, Shenbao Jin, Gang Sha, Nasr Ghoniem, Ze Zhang, Y. Morris Wang

Summary: Additive manufacturing enables self-stabilization of dislocations in metallic materials through heating-cooling cycles, resulting in a unique dislocation assembly that enhances material strength and steady strain hardening.

Article Chemistry, Multidisciplinary

Investigation on the Strengthening Mechanisms of Nickel Matrix Nanocomposites

Iris Carneiro, Jose Valdemar Fernandes, Sonia Simoes

Summary: The study aims to identify several strengthening mechanisms in metal matrix nanocomposites, and in the case of the Ni-CNT nanocomposite, four different mechanisms were found to play a role, including load transfer, increase in dislocation density, grain refinement, and presence of second phase particles.

Article Materials Science, Multidisciplinary

A TiC reinforced Co-free Fe50Mn25Ni10Cr15 medium-entropy alloy with multiple strengthening mechanisms

Zhaohuan Song, Shengying Sun, Haonan Du, Ruitong Han, Xiliang Zhang, Qian Zhou, Zheng Lv, Ran Wei, Hongji Liu

Summary: High-yield-strength and ductile (Fe50Mn25Ni10Cr15)100-x(TiC)x medium-entropy alloys (MEAs) were prepared. The yield strength of the 0.5 at.% TiC reinforced sample increased from -250 MPa to 450 MPa at 298 K and from -460 MPa to -649 MPa at 77 K, compared to TiC-free samples, while retaining sufficient ductility. The improved yield strength is attributed to the synergistic effect of fine grain strengthening, Orowan strengthening, and HDI strengthening.

Article Nanoscience & Nanotechnology

Strengthening mechanisms and modelling of mechanical properties of submicron-TiB2 particulate reinforced Al 7075 metal matrix composites

Barada Prasanna Sahoo, Diptikanta Das, Anil Kumar Chaubey

Summary: This paper investigates the physics of matrix-reinforcement consonance in metal matrix composites and the effects of various strengthening mechanisms on mechanical properties of Al 7075/submicron-TiB2 MMCs. Analytical models were proposed to predict elastic modulus and yield strength, and were validated with experimental results and established models, showing reasonable agreement especially at higher volume fractions of particle incorporation.

Article Nanoscience & Nanotechnology

Kinematical barriers enhanced dislocation strengthening mechanisms in cold-worked austenitic steels

Tian Zhang, Jie Tang, Shudong He, Fulin Jiang, Dingfa Fu, Jie Teng, Jian Wang

Summary: We experimentally investigated the microstructure evolution and strengthening behaviors of three cold-worked austenitic steels that deform via dislocations, twinning, and stacking faults. It was found that the development of stacking faults and twins acts as kinematical barriers for dislocation motion, which is influenced by stacking fault energy and accumulated dislocations. These factors accelerate the dislocation storage rate, strengthen the alloys, and develop a high strain hardening rate. Therefore, we proposed a nonadditive strengthening equation by combining the dislocation-based two-internal-variable model coupled with kinematical barriers to rationalize the experimental observations.

Article Materials Science, Multidisciplinary

Microstructural Effect on Cold Strengthening Mechanism of MP159 Alloys

Luorong Dengzhu, Leiming Fang, Bin Gan, Zhengwei Xiong, Qian Liu, Yi Liu, Jia Yang, Jun Li, Zhipeng Gao

Summary: This study elucidates the microstructural changes induced by cold deformation on MP159 alloy through multi-scale structural characterizations. The results show that cold deformation refines the grains, breaks the grain boundaries and transforms them into low-angle grain boundaries, leading to significant enhancement of strength and hardness in the alloy.

Article Chemistry, Physical

Effect of micro-alloying element Ti on mechanical properties of Cu-Cr alloy

Huaichao Peng, Weibin Xie, Huiming Chen, Hang Wang, Bin Yang

Summary: After aging treatment, the mechanical properties and microstructure of Cu-Cr and Cu-Cr-Ti alloys were improved significantly, with enhanced hardness, yield strength, and softening temperature. The strengthening mechanism of Cr precipitates was identified as the Orowan strengthening relation, contributing to the high dislocation density observed in the Cu-Cr-Ti alloy matrix. Dislocation strengthening, solid-solution strengthening, and precipitate strengthening were found to remarkably enhance the yield strength.

Article Materials Science, Multidisciplinary

Enhanced strength in pure Ti via design of alternating coarse- and fine-grain layers

Danyang Li, Guohua Fan, Xiaoxu Huang, Dorte Juul Jensen, Kesong Miao, Chao Xu, Lin Geng, Yubin Zhang, Tianbo Yu

Summary: A specially designed layered titanium with alternating coarse- and fine-grain layers (C/F-Ti) shows an extraordinarily high yield strength beyond predicted values, with the strengthening mechanism investigated through experimental characterizations. The enhanced interface constraint effect on deformation mechanism in hexagonal close-packed (hcp) materials is highlighted, demonstrating a new structural design strategy for property optimization.

Article Nanoscience & Nanotechnology

Grain refinement and strengthening of 316L stainless steel through addition of TiC nanoparticles and selective laser melting

Wengang Zhai, Wei Zhou, Sharon Mui Ling Nai

Summary: The strength of 316L stainless steel was significantly increased by the addition of TiC nanoparticles, while maintaining a high level of ductility. The increase in strength was primarily due to Orowan strengthening from the nanoparticles, and the reduction in ductility was related to the suppression of twinning induced plasticity.

Article Materials Science, Multidisciplinary

Strengthening Effect of Decreased Dislocation Density After Annealing in Pure Aluminum or Copper

Eun-Ae Choi, Yun Soo Lee, Sang Jin Lee, Jee Hyuk Ahn, Sung Hwan Lim, Satoshi Semboshi, Seung Zeon Han

Summary: Plastic deformation in metals occurs through the generation and movement of dislocations, which increase strength. This study observed the effect of dislocation configuration and reaction with grain boundaries on strength and discovered a hidden mechanism in work hardening.

Article Materials Science, Multidisciplinary

Modeling peak-aged precipitate strengthening in Al-Mg-Si alloys

Yi Hu, W. A. Curtin

Summary: Strengthening in Al-Mg-Si alloys by needle-shaped beta'' precipitates is crucial, with computational studies showing that Orowan looping only sets an upper bound for the CRSS even at peak aging. Further quantitative progress in understanding the strengthening mechanism requires detailed modeling of precipitate shearing.

Article Chemistry, Physical

Effect of vacancy defects of graphene on the interfacial bonding and strengthening mechanism of graphene/Al composite

Boyu Ju, Wenshu Yang, Jinpeng Sun, Zhichao Han, Qiang Zhang, Ziyang Xiu, Gaohui Wu

Summary: The interfacial structure and bonding strength of graphene-Al interface with different vacancy defect types were investigated by first-principle calculations. The interfacial shear strengths of defect-free, single-vacancy, and double-vacancy were 0.02 GPa, 6.8 GPa, and 8.5 GPa, respectively. A calculation model for shear strength of graphene-Al interface with different defect contents was established and a method to estimate the shear strength based on Raman characterization of graphene defects was proposed.

Article Materials Science, Multidisciplinary

Heterostructured titanium composites with superior strength-ductility synergy via controllable bimodal grains and <c plus a> dislocation activity

Jiajing Chen, Yuanfei Han, Zichao Wei, Shaopeng Li, Zhonggang Sun, Liang Zhang, Guangfa Huang, Jianwen Le, Di Zhang, Weijie Lu

Summary: A novel and controllable strategy of simple powder assembly is proposed to fabricate heterostructured metal matrix composites, which breaks the strength-ductility trade-off dilemma and enhances < c+a > dislocation activity.

Article Chemistry, Physical

Evolution and strengthening mechanism of metastable precipitates in Cu-2.0 wt% Be alloy

Weiwei Zhang, Zhihe Zhao, Jihua Fang, Ping He, Zhenlong Chao, Deng Gong, Guoqin Chen, Longtao Jiang

Summary: This study mainly discusses the structure, quantity, size, and strengthening mechanisms of the gamma '' phase and gamma' phase in Cu-2.0 wt% Be alloy. With the increase of aging temperature, the characteristics of these two phases change to different degrees.

Article Materials Science, Multidisciplinary

Strengthening Mechanisms of Aluminum Matrix Nanocomposites Reinforced with CNTs Produced by Powder Metallurgy

Iris Carneiro, Jose Valdemar Fernandes, Sonia Simoes

Summary: This study investigates the strengthening mechanisms in aluminum matrix nanocomposites reinforced by carbon nanotubes (CNTs) using powder metallurgy techniques. The key for nanocomposite production is achieving uniform dispersion of CNTs without damaging their structure. The observed improvement in the mechanical properties can be attributed to load transfer from the matrix to the CNTs as well as strain hardening and second-phase hardening contributions.

Review Materials Science, Multidisciplinary

Deformation Behavior of 3D-Printed High-Entropy Alloys: A Critical Review

Dhruv Bajaj, Aihan Feng, Shoujiang Qu, Zhuo Chen, Dongyang Li, Daolun L. Chen

Summary: The 3D printing of high-entropy alloys (HEAs) offers greater flexibility in designing and manufacturing novel materials. These 3D-printed HEAs exhibit unique microstructures and mechanical properties, breaking the limitations of conventionally-manufactured materials. This review provides insight into the deformation behavior of 3D-printed HEAs, with emphasis on fatigue characteristics and the effects of postfabrication thermomechanical processing.

Article Materials Science, Ceramics

Fatigue behavior of silicon nitride ceramics

C. C. Ye, H. Q. Ru, D. L. Chen

Summary: This study aimed to investigate the effects of sintering additives on the fatigue life of silicon nitride (Si3N4) ceramics sintered via hot pressing, focusing on the prominent toughening mechanisms. The fatigue life and probability of survival of YMH samples using MgO and Y2O3 as sintering additives were found to be higher than those of YAH samples using Al2O3 and Y2O3 as sintering additives. This was attributed to the higher aspect ratio of the elongated β-Si3N4 grains, larger compressive residual stresses, and the presence of only amorphous (or glassy) phase at β-Si3N4 grain boundaries in the YMH sample.

Article Automation & Control Systems

Dissimilar ultrasonic spot welding of ZEK100 magnesium alloy to a clad AA7075 aluminum alloy: Tensile and fatigue properties

Soumya Sobhan Dash, Mudit Kesharwani, Abdulmohsen Albedah, Xianquan Jiang, Dongyang Li, Daolun Chen

Summary: The study aimed to investigate the feasibility of joining ZEK100-O magnesium alloy to AA7072-clad high-strength AA7075-T6 aluminum alloy using solid-state ultrasonic spot welding (USW). The interfacial microstructures, tensile lap shear strength, and fatigue resistance were evaluated. Mechanical interlocks and a diffusion layer were observed at the weld interface, resulting in enhanced tensile lap shear strength and fatigue life.

Article Materials Science, Multidisciplinary

Achieving superior strength-ductility synergy in a heterostructured magnesium alloy via low-temperature extrusion and low-temperature annealing

H. Wang, D. T. Zhang, C. Qiu, W. W. Zhang, D. L. Chen

Summary: A low-alloyed Mg-1.2Zn-0.1Ca alloy was fabricated via low-temperature extrusion and annealing to attain heterostructures with different fine-grained fractions, showing significant effects on the mechanical properties. The alloy exhibited increased fine-grained fraction and fine grain size with annealing, resulting in superior mechanical properties of high yield strength and good ductility. Hetero-deformation induced strengthening plays a key role in achieving the superior mechanical properties.

Article Materials Science, Multidisciplinary

Adiabatic shear instability in a titanium alloy: Extreme deformation-induced phase transformation, nanotwinning, and grain refinement

X. R. Guan, Q. Chen, S. J. Qu, G. J. Cao, H. Wang, A. H. Feng, D. L. Chen

Summary: Increasingly harsh service conditions require better high strain-rate performance of titanium alloys. Adiabatic shear band (ASB), which is prone to dynamic loading, often leads to catastrophic damage. However, the relationship between internal nanostructures and shear instability remains unclear.

Article Nanoscience & Nanotechnology

Effects of Al and Ti on microstructure, mechanical properties and wear resistance of TiXCrFe2Ni2 alloys

G. J. Diao, A. Q. He, Y. Q. Tang, M. Y. Wu, D. Zhang, W. G. Chen, D. L. Chen, D. Y. Lia

Summary: The individual effects of Al and Ti on microstructure, mechanical and tribological properties of CrFe2Ni2 alloy were investigated. Al addition changed the alloy phase from FCC to a mixture of FCC, A2 and B2 phases, increasing the mechanical strength while slightly sacrificing ductility. Ti caused the formation of hard phases in the alloy, increasing the wear resistance, but also decreasing the ductility. Detailed characterization is crucial for optimizing tribological applications of relevant HEAs.

Article Engineering, Mechanical

Influence of solution-hardening on the mechanical properties and wear resistance of copper alloys

Aakash Kumar, Yunqing Tang, D. Y. Li, D. L. Chen, Wei Li, Q. Y. Li

Summary: Solid-solution hardening can improve the wear resistance of metals by pinning dislocations and affecting the atomic bond strength and Young's modulus. Cu was hardened by Ni and Mn, resulting in increased hardness and Young's modulus with Ni addition, and decreased Young's modulus but increased hardness with Mn addition. However, the effect of Ni and Mn on wear resistance is underestimated or overestimated by using the classic Archard equation, which can be corrected by a wearing energy model taking into account the influence of Young's modulus.

Article Engineering, Mechanical

Bauschinger effect on wear of cold-worked Cu and Mg-A study combining molecular dynamics modeling and experimental investigation

Y. Q. Tang, A. Kumar, D. L. Chen, D. Y. Li, Q. Y. Li, W. Li

Summary: The Bauschinger effect, which refers to the decrease in yield strength of a metal after plastic deformation in the opposite direction prior to testing, affects the wear resistance of materials under different conditions. This study investigated the influence of the Bauschinger effect on the wear resistance of strain-hardened Cu (FCC) and Mg (HCP) through experiments and molecular dynamics simulations. It was observed that strain-free Cu exhibited a stronger Bauschinger effect, while the situation was reversed for undeformed and deformed Mg samples. The underlying mechanisms were studied through molecular dynamics simulations, revealing that high-density dislocations weaken the Bauschinger effect in cold-worked Cu, while cold-worked Mg with fewer defects has more space for defect generation and cancellation, resulting in a stronger Bauschinger effect. Additionally, the Bauschinger effect was found at the oxide/metal interface, making the oxide scale on worn surfaces less prone to being scratched off during bi-directional sliding, thus enhancing the wear resistance of the metal.

Article Engineering, Mechanical

Influences of alloying elements on microstructure and tribological properties of a medium-weight high-entropy alloy

S. E. Mousavi, A. Q. He, M. Palimi, D. L. Chen, D. Y. Li

Summary: The individual influences of Al, Fe and Ni on the microstructure, wear resistance and mechanical properties of high-entropy alloys (AlxCrFeyNizTi0.2) were studied. It was found that increasing Al content led to the replacement of the FCC phase by disordered and ordered BCC phases, resulting in increased micro-hardness and decreased wear volume loss. Fe increased the fraction of A2 phase but reduced hardness and wear resistance. Ni helped form a FCC phase, which decreased hardness and increased wear volume loss. Among all specimens, AlCrFeNiTi0.2 and Al0.5CrNiTi0.2 showed the highest wear resistance.

Article Nanoscience & Nanotechnology

On the origin of deformation mechanisms in a heterostructured aluminum alloy via slip trace and lattice rotation analyses

S. S. Dash, D. J. Li, X. Q. Zeng, D. Y. Li, D. L. Chen

Summary: In this study, the micro-deformation mechanisms in an Al-Si cast alloy under stepwise compressive loading were investigated using EBSD and slip trace analyses. The presence of heterogeneous microstructural features significantly influenced the slip trace characteristics. Four types of slip traces in primary α-Al grains were identified, revealing the nature of dislocation motion and the extent of deformation difficulty associated with grain orientations and eutectic Si particles. Crystallographic factors were analyzed to understand the deformation behavior of the alloy.

Article Nanoscience & Nanotechnology

Deformation behavior of a newly-developed T4-treated Al-Si die cast alloy

S. S. Dash, D. J. Li, X. Q. Zeng, D. Y. Li, D. L. Chen

Summary: The aim of this study is to investigate the monotonic and cyclic deformation behavior of a high-pressure die cast Silafont (R)-36 alloy in a naturally-aged T4 state. The T4 heat treatment led to significant microstructural changes, resulting in the transformation of coralloid-like eutectic Si particles to spheroidal Si particles embedded in the Al matrix. The T4 alloy exhibited strong cyclic hardening and a longer low cycle fatigue life compared to its as-cast state at lower strain amplitudes, attributed to particle-dislocation interactions during deformation. A strain energy density-based model incorporating microstructural aspects can be used to predict the fatigue life of the T4 alloy.

Article Materials Science, Multidisciplinary

Investigation of Mechanical Properties and Wear Resistance of A2/B2 Type Medium-Entropy Alloy Matrix Reinforced with Tungsten Particles by In-Situ Reaction

Mingyu Wu, Guijiang Diao, Zhen Xu, Ruiken Sim, Wengang Chen, Daolun Chen, Dongyang Li

Summary: Microstructure, mechanical properties, wear resistance, corrosion and corrosive wear resistance of AlCrFeNiWx (x = 0, 0.1, 0.2, 0.3 and 0.4) medium-entropy alloys (MEAs) prepared by vacuum arc melting process were investigated. Tungsten addition in AlCrFeNi alloy significantly improves its hardness, strength, pitting resistance and passivation property, while excessive W addition reduces ductility. AlCrFeNiW0.3 shows the highest corrosion resistance and W enhances the wear and corrosive wear resistance in AlCrFeNiW0.4.

Review Materials Science, Multidisciplinary

A Review on Processing-Microstructure-Property Relationships of Al-Si Alloys: Recent Advances in Deformation Behavior

Soumya Sobhan Dash, Daolun Chen

Summary: This review focuses on recent developments in the processing, structure, and mechanical properties of structural Al-Si alloys, aiming to address pressing environmental issues and achieve lightweighting strategies. It summarizes advancements in casting methods and additive manufacturing processes, analyzes improvements in thermal stability, electrical conductivity, and mechanical strength, and discusses fatigue failure mechanisms and surface topography.

Article Materials Science, Multidisciplinary

Small-depth nanoindentation studies of an additively manufactured titanium alloy: Anisotropic nanomechanical properties and correlation with microscopic mechanical behaviour

Zhiying Liu, Lizhong Lang, S. M. A. K. Mohammed, Daolun Chen, Bei He, Yu Zou

Summary: Nanoindentation is widely used for measuring local mechanical properties of heterogeneous materials. In this study, a nanoindentation mapping method with small indentation depths (<200 nm) is used to investigate the nanohardness (H) of the alpha phase in an additively manufactured titanium alloy. The results reveal two groups of H values exhibited by alpha grains with different crystal orientations, in contrast to the wide range of H values measured by conventional large-depth nanoindentation. These two groups of H values are attributed to the contribution of elasticity in the measurement using small-depth nanoindentation. Additionally, the H values are correlated with the microscopic mechanical behavior of alpha grains, showing that hard alpha grains are deformed by shear banding while soft alpha grains are deformed by dislocation slip.

Article Metallurgy & Metallurgical Engineering

Achieving Superior Superplasticity in a Mg-6Al-Zn Plate via Multi-pass Submerged Friction Stir Processing

Xicai Luo, Haolin Liu, Limei Kang, Jielin Lin, Datong Zhang, Dongyang Li, Daolun Chen

Summary: A large-scale Mg-6Al-Zn plate was prepared by M-SFSP, showing excellent superplastic deformation behavior at high temperature and low strain rate, with different orientations affecting the maximum elongation rate.

Article Nanoscience & Nanotechnology

The effect of annealing on kink band formation in Ag/Fe nanolaminates

Yifan Zhang, Thomas J. Nizolek, Laurent Capolungo, Nan Li, John S. Carpenter, Rodney J. McCabe

Summary: In this study, the effect of annealing on kink band (KB) formation in Ag/Fe nano metallic laminates (NMLs) was investigated. The results showed that annealing increased the KB initiation strain, decreased the probability of KB formation, and decreased the load drop magnitude accompanying kink banding in Ag/Fe NMLs. Post-compression analyses revealed that annealing facilitated more uniform deformation of pillars and affected the formation of geometrically necessary grain boundaries (GNBs) near the kink band boundary (KBB). Annealed Ag/Fe exhibited wider KBs with blunter KBBs compared to its as-rolled counterpart.

Article Nanoscience & Nanotechnology

Bis (8-hydroxyquinoline) zinc complex derived ZnO@N-doped carbon composite for enhancing lithium storage performance

Jian Chen, Na Zhao, Jin-Duo Han, Bao-Bao Wang, Yi-Fan Gao

Summary: Hierarchical porous ZnO@N-doped carbon composites were synthesized via one-pot thermal decomposition of bis(8-hydroxyquinoline) zinc complex at different calcination temperatures. The in-situ N-doped carbon effectively enhanced electronic conductivity and hindered the aggregation and growth of ZnO particles. The nanoscale particle size and porous structure characteristics contributed to improved electrochemical reaction dynamics and minimized the impact of volume change on electrochemical performance during cycling. Galvanostatic charge/discharge tests demonstrated that the ZnO@N-doped carbon sample synthesized at 600°C exhibited the highest charge/discharge specific capacity, best rate capability, and excellent cycle stability under low and high current densities, suggesting promising applications as anode materials, particularly in fields requiring high energy and power density Li-ion batteries.

Article Nanoscience & Nanotechnology

Wide tuning the carbon supersaturation within Fe-C lath martensite via high pressure martensitic transformation of Fe-0.45C alloy

Haidong Sun, Zuohua Wang, Lihua Qian, Peng Wang, Jian Zhao, Wu Zhang, Dongli Yu, Hongwang Zhang

Summary: The carbon supersaturation within the lath martensitic lattice was adjusted by thermally treating a Fe-0.45C alloy under hydrostatic pressures of 1-6 GPa. The amount of supersaturated carbon increased linearly with high pressure, reaching up to 84.4% of the nominal carbon content under 6 GPa. The strengthening effect of carbon supersaturation remained proportional to the square root of its content, but the contribution was underestimated.

Article Nanoscience & Nanotechnology

Diffusion controlled early-stage L12-D023 transitions within Al3Zr

Shiwei Pan, Chunan Li, Feng Qian, Longlong Hao, Yanjun Li

Summary: The detailed atomic structures of conservative {100} APBs within L12-Al3Zr particles forming at the early-stage of L12-D023 transition in an Al-Zr alloy were systematically studied by high angle annual dark-field scanning transmission electron microscope (HAADF-STEM). It is suggested that L12-D023 phase transition has been achieved through a diffusion mechanism, instead of shearing mechanism while the formation of APB is an intermediate stage of the phase transition process. First principles density functional theory (DFT) reveals that the formation of APBs and subsequent phase transition are energetically favorable, which provide the driving force for diffusion.

Article Nanoscience & Nanotechnology

Achieving outstanding heat-resistant Mg-Gd-Y-Zn-Mn alloy via introducing RE/Zn segregation on & alpha;-Mn nanoparticles

Xiaojun Luo, Hong Yang, Jianxin Zhou, Bin Jiang, Qingguo Feng, Ying Zeng, Wei Li, Zhihua Dong, Jiangfeng Song, Junyao Xu, Guangsheng Huang, Dingfei Zhang, Fusheng Pan

Summary: A novel Mg-8Gd-2Y-1.5Zn-1Mn (GYZ-1Mn) alloy with exceptional high-temperature mechanical properties was developed by introducing RE/Zn segregation on α-Mn nanoparticles. The outstanding performance of GYZ1Mn alloy was attributed to the segregation of RE/Zn atoms on the α-Mn nanoparticles, which promoted the formation of fine lamellar long period stacking ordered (LPSO) phase and hindered the coarsening of α-Mn. As a result, delayed dynamic recrystallization occurred in GYZ-1Mn, resulting in fine grain size, high density of geometrically necessary dislocations, and strong fiber texture intensity, thereby strengthening the high-temperature mechanical properties. Therefore, this work paved a new path for the development of heat-resistant Mg alloys by introducing elemental segregation on nanoparticles.

Article Nanoscience & Nanotechnology

The ultrahigh damping capacity of Mg-Sn-Y alloy

Lunchao Zhang, Yuan Yuan, Jun Wang, Tao Chen, Jingfeng Wang, Fusheng Pan

Summary: High temperature heat treatment Mg-0.69Sn-0.69Y alloy exhibited a high damping capacity (0.201 at epsilon=1 x 10-3) and a very low critical strain amplitude at room temperature (epsilon cr1=2.97 x 10-5), which can be ascribed to the combined effects of purified matrix phase and subgrain interfaces. The substructure is unstable and the damping capacity decreases with temperature increment.

Article Nanoscience & Nanotechnology

Extra-ductile and strong tin bronze alloy via high-density intragranular ultra-nano precipitation with minimal lattice misfit

Kaixuan Chen, Jiangxu Shen, Zongxuan Li, Xiangkai Chen, Kaisheng Ming, Yuzhi Zhu, Xiaohua Chen, Tianxin Weng, Zidong Wang

Summary: In this study, we present an intragranular ultra-nano precipitation strategy to enhance the plasticity and strength of polycrystalline Cu alloys. The strategy involves the dispersion of extremely fine Fe nanoprecipitates with minimal lattice misfit inside Cu grains. These ultra-nano particles significantly improve the tensile ductility and strength of a plasticity-poor tin bronze alloy, resulting in more stable and greater work hardening. We believe that this intragranular ultra-nano precipitation strategy can be applied to other metallic alloys.

Article Nanoscience & Nanotechnology

Flash sintering improves magnetic properties of spinel zinc ferrite

Soumyadeep Sur, Parmanand Kumar Tyagi, Shikhar Krishn Jha

Summary: We present a simple protocol for one step synthesis and sintering of single-phase magnetic spinel ZnFe2O4 zinc ferrite (ZFO) using electric field assisted sintering, resulting in improved saturation magnetization and higher coercivity compared to conventionally sintered ferrite. The changes in properties can be attributed to generation of non-thermal lattice defects when processed under electric field. This method allows for sintering of ZFO at a lower temperature and shorter time compared to traditional sintering processes, making it a more efficient approach.

Article Nanoscience & Nanotechnology

High-resolution 3D strain and orientation mapping within a grain of a directed energy deposition laser additively manufactured superalloy

Y. Chen, Y. T. Tang, D. M. Collins, S. J. Clark, W. Ludwig, R. Rodriguez-Lamas, C. Detlefs, R. C. Reed, P. D. Lee, P. J. Withers, C. Yildirim

Summary: The industrialization of Laser Additive Manufacturing (LAM) faces challenges such as undesirable microstructures and high residual stresses. Non-destructive assessment of mechanical performance is crucial, and Dark Field X-ray Microscopy (DFXM) is used to map the 3D subsurface intragranular orientation and strain variations of a surface-breaking grain in a nickel superalloy. DFXM results show a highly heterogeneous microstructure with alternating strain states and small orientation differences. Comparison with Electron Backscatter Diffraction measurements is also discussed.

Article Nanoscience & Nanotechnology

Linear response for temperature sensing achieved by implanting Er3+into the grain boundary of transparent MgAlON ceramic

Bowen Chen, Bin Wang, Zhengyang Jing, Hao Wang, Bingtian Tu, Weimin Wang, Zhengyi Fu

Summary: In this study, a fluorescence thermometry method based on MgAlON:0.01 at.% Er3+ transparent ceramic was successfully proposed by employing the idea of local structural engineering. The special local environment of Er3+ in the grain boundary led to different fluorescence responses from crystalline or amorphous structures. By measuring the linear downshift fluorescence intensity ratio of thermally coupled energy levels of Er3+ with temperature, a constant absolute sensitivity (0.0156 K-1) was obtained within the tested temperature range (300-573 K). This work highlights the significance of the local structure of the activators in the design of high-performance fluorescence temperature sensors.

Article Nanoscience & Nanotechnology

Effect of amorphous complexions on plastic deformation of nanolayered composites

Zhe Yan, Zhaorui Liu, Bonan Yao, Qi An, Ruifeng Zhang, Shijian Zheng

Summary: Interface-induced dislocation nucleation and interface sliding are two decisive mechanisms for understanding the plastic deformation of nanolayered composites. By conducting atomic simulations on the Cu-Nb system, the atomic mechanisms of dislocation nucleation and interface sliding are revealed after introducing CuNb amorphous complexions with different compositions. These findings demonstrate the influence of amorphous complexions on plastic deformation and provide theoretical guidance for the design of nanolayered composites.

Article Nanoscience & Nanotechnology

First-principles investigation of the effect of interfacial compositions on the formation energies of ?? and T1 structures

S. L. Yang, Y. K. Niu, J. Z. Liu, N. Wilson, J. F. Nie

Summary: The formation energies of ohm ' and T1 precipitates with different interfacial compositions were calculated using density functional theory. The results showed that the presence of Ag and Mg and/or Li at the top and bottom layers significantly increased the favorability of precipitate formation. The effect of Ag, with a similar atomic size to Al, was dominated by chemical bonding, while the larger atoms of Mg and Li reduced the formation energy through elastic strain reduction. These findings provide insights into enhancing the formation of specific strengthening constituents through micro-alloying with appropriate elements.

Article Nanoscience & Nanotechnology

A novel additive manufactured reduced activation ferritic/martensitic steel enhanced by in-situ nanoparticles benefiting from oxygen addition

Shubo Zhang, Kailun Li, Wenjing Zhang, Menghan Ma, Mingshen Li, Jing Xue, Hao Chen, Rong Hu, Wei Liu

Summary: This study presents a new type of iron-based alloy with nano particles, manufactured using selective laser melting, to enhance high-temperature performance. The results show superior mechanical properties compared to other additive manufactured alloys, suggesting the potential for improving structural materials in fusion reactors.

Article Nanoscience & Nanotechnology

Ultra-fine microstructure and exceptional low coercivity developed in a high-Bs Fe-Si-B-P alloy by co-alloying Ni, Mo, and Cu

Fayuan Shen, Bowen Zang, Lijian Song, Juntao Huo, Yan Zhang, Jun-Qiang Wang

Summary: Designing soft magnetic alloys with high saturation magnetic induction (Bs) is crucial for enhancing the power density of electric and electronic devices. In this study, novel Fe-based nanocrystalline alloys were developed by microalloying a Fe-Si-B-P alloy, with the addition of Ni, Mo, and Cu. The microstructure of the alloys was effectively refined, resulting in a decrease in grain size from 28.5 nm to 13.1 nm, and improved stability of soft magnetic properties. After nanocrystallization, the alloys exhibited exceptional magnetic properties, including low coercivity (1-2 A/m) and high Bs (1.81 T), which could be maintained within a wide annealing temperature and time window.

Article Nanoscience & Nanotechnology

Anharmonicity in grain boundary energy for Al: Thermodynamic integration with artificial-neural-network potential

M. Matsuura, T. Yokoi, Y. Ogura, K. Matsunaga

Summary: The anharmonicity in grain boundary (GB) energies for Al has been studied using a thermodynamic integration method with a high-accuracy artificial-neural-network potential. It is found that anharmonic components are small at low temperatures but increasingly contribute to the reduction of GB free energies at higher temperatures. The magnitude of anharmonicity is roughly correlated with excess volume at GBs, and for certain GBs, there is a significant deviation from the harmonic approximation.