Acta Materialia最新文献

{"title":"Parameterization of a phase field model for ferroelectrics from molecular dynamics data","authors":"Dilshod Durdiev ,&nbsp;Frank Wendler ,&nbsp;Michael Zaiser ,&nbsp;Hikaru Azuma ,&nbsp;Takahiro Tsuzuki ,&nbsp;Shuji Ogata ,&nbsp;Tomohiro Ogawa ,&nbsp;Ryo Kobayashi ,&nbsp;Masayuki Uranagase","doi":"10.1016/j.actamat.2024.120513","DOIUrl":"10.1016/j.actamat.2024.120513","url":null,"abstract":"<div><div>In this work, molecular dynamics (MD) simulations of ferroelectric BaTiO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> are used to generate parameters for a phase-field (PF) model. The MD simulations provide important input parameters, such as elastic and piezoelectric properties, as well as domain wall (DW) widths and velocities. A parameterization technique is proposed to incorporate the MD results into the PF simulations, allowing for the generation of relevant parameters. Anisotropic interface energy coefficients are used to match the widths of both the 180° and 90° DWs in the PF simulations to the MD data. The velocities of the DWs are calculated and compared to the results obtained from MD simulations, demonstrating excellent agreement. Furthermore, we investigate the disparity between coercive fields obtained from PF simulations and MD simulations. Initially, our PF simulations yield coercive fields approximately twice as high as those observed in MD simulations. To address this discrepancy, we introduce a nucleus into the PF simulation system. The parameters of this nucleus are derived from a statistical analysis of coercive field data from MD simulations. By incorporating the nucleus model, we achieve a coercive field in PF simulations that closely aligns with the MD results. Validation of the parameterized PF model using MD data obtained with different initial conditions and thermodynamic constraints shows good agreement, further confirming the model’s accuracy.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120513"},"PeriodicalIF":8.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crossover strain glass alloy exhibiting large recoverable strain over a wide temperature range","authors":"Yu Qian ,&nbsp;Wenjia Wang ,&nbsp;Yu Wang ,&nbsp;Andong Xiao ,&nbsp;Yao Liu ,&nbsp;Ge Zhang ,&nbsp;Zhizhi Xu ,&nbsp;Yun Pan ,&nbsp;Guanqi Wang ,&nbsp;Xiaobing Ren ,&nbsp;Yuanchao Ji","doi":"10.1016/j.actamat.2024.120533","DOIUrl":"10.1016/j.actamat.2024.120533","url":null,"abstract":"<div><div>Superelastic alloys, being successfully used in cutting-edge space technologies, are desired to possess large recoverable strain and wide working temperature range simultaneously. However, achieving such a combination has proven challenging. Here we report a finding of crossover strain glass transition in the crossover region between martensite and strain glass regimes of temperature vs. annealing-time phase diagram of cold-rolled Ti₅₀Ni₅₀ alloys. The crossover strain glass alloy exhibits a large recoverable strain of ∼ 4%-6% and ultrawide working temperature range from 453 to 93 K, outperforming previously reported superelastic alloys. Moreover, such exceptional properties were revealed to stem from the crossover strain glass transition occurring at a high transition temperature <em>T</em>_g ∼ 276 K, which possesses a unique transition behavior of strain glass transition accompanied by a sluggish and partial martensitic transformation from strain glass to martensite with cooling. This transition was further characterized by <em>in-situ</em> microscopic observations: upon cooling both several nanometer-sized and dozens of nanometer-sized B19’ martensitic domains gradually appear and increase in the matrix of B2 parent phase over a wide temperature range, which contribute to large recoverable strain and ultrawide working temperature range. Our work indicates that the crossover strain glass may provide a new mechanism to achieve large recoverable strain over a wide temperature range, and large field-induced strain over a wide temperature range may be obtained in other crossover ferroic glasses.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120533"},"PeriodicalIF":8.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlative activation free energy (CAFE) model: Application to viscous processes in inorganic oxide glass-formers","authors":"Cameran Beg,&nbsp;Jaemin Byeon,&nbsp;Nova Berman,&nbsp;John Kieffer","doi":"10.1016/j.actamat.2024.120538","DOIUrl":"10.1016/j.actamat.2024.120538","url":null,"abstract":"<div><div>We explore the concept of correlative activation free energy (CAFE) for the analysis and interpretation of viscosity data of a collection of 847 inorganic oxide glass formers that exhibit various degrees of non-Arrhenius behavior. The CAFE model formalism is strictly based on transition state theory and accounts for the variation in the activation barrier height for the viscous dissipation due to the structural evolution the system undergoes upon traversing the glass transition regime. Thus, fitting parameters are meaningful in a statistical thermodynamic context. Compared to the VFT and MYEGA equations, fits using the CAFE model are more robust when extrapolating to infinite temperature because the latter encodes non-enthalpic contributions to the rate coefficient more realistically. The CAFE model-based analysis reveals a strong connection between melt fragility and the degree of change in the potential energy landscape with temperature. Accordingly, while the average ground-state potential energy of the glass forming liquid gradually increases with temperature, the energy of the activated state remains relatively invariant. Our analysis also allows one to estimate the number of atoms involved in the viscous relaxation process, which ranges from approximately 10 to 50 atoms for the oxide glass formers studied. We observe that thermally activated dynamic phenomena exhibited by glassy networks, such as the mixed alkali effect, persist into the supercooled liquid state.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120538"},"PeriodicalIF":8.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Substrate Polarity on Thermal Stability, Grain Growth and Atomic Interface Structure of Au Thin Films on ZnO Surfaces","authors":"Martin Dierner, Michael Landes, Johannes Will, Andreas Ziegler, Sabine Hübner, Thomas Przybilla, Tobias Zech, Tobias Unruh, Bernd Meyer, Erdmann Spiecker","doi":"10.1016/j.actamat.2024.120531","DOIUrl":"https://doi.org/10.1016/j.actamat.2024.120531","url":null,"abstract":"The influence of the polarity of ceramic substrates on the structural evolution of thin metal films during annealing at elevated temperatures is investigated, including the competing processes of solid state dewetting (SSD) and grain growth, as well as the atomic structure of the epitaxial interface. For this purpose, Au thin films on polar O-ZnO&lt;span&gt;&lt;span style=\"\"&gt;&lt;/span&gt;&lt;span data-mathml='&lt;math xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow is=\"true\"&gt;&lt;mo is=\"true\"&gt;(&lt;/mo&gt;&lt;mrow is=\"true\"&gt;&lt;mn is=\"true\"&gt;000&lt;/mn&gt;&lt;mover accent=\"true\" is=\"true\"&gt;&lt;mn is=\"true\"&gt;1&lt;/mn&gt;&lt;mo is=\"true\"&gt;&amp;#xAF;&lt;/mo&gt;&lt;/mover&gt;&lt;/mrow&gt;&lt;mo is=\"true\"&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"&gt;&lt;svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 2851 1196.3\" width=\"6.622ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;&lt;g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"&gt;&lt;g is=\"true\"&gt;&lt;use is=\"true\" xlink:href=\"#MJMAIN-28\"&gt;&lt;/use&gt;&lt;g is=\"true\" transform=\"translate(389,0)\"&gt;&lt;g is=\"true\"&gt;&lt;use xlink:href=\"#MJMAIN-30\"&gt;&lt;/use&gt;&lt;use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"&gt;&lt;/use&gt;&lt;use x=\"1001\" xlink:href=\"#MJMAIN-30\" y=\"0\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;g is=\"true\" transform=\"translate(1501,0)\"&gt;&lt;g is=\"true\" transform=\"translate(35,0)\"&gt;&lt;use xlink:href=\"#MJMAIN-31\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;g is=\"true\" transform=\"translate(0,198)\"&gt;&lt;use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"&gt;&lt;/use&gt;&lt;use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;/g&gt;&lt;/g&gt;&lt;use is=\"true\" x=\"2461\" xlink:href=\"#MJMAIN-29\" y=\"0\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;/g&gt;&lt;/svg&gt;&lt;span role=\"presentation\"&gt;&lt;math xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow is=\"true\"&gt;&lt;mo is=\"true\"&gt;(&lt;/mo&gt;&lt;mrow is=\"true\"&gt;&lt;mn is=\"true\"&gt;000&lt;/mn&gt;&lt;mover accent=\"true\" is=\"true\"&gt;&lt;mn is=\"true\"&gt;1&lt;/mn&gt;&lt;mo is=\"true\"&gt;¯&lt;/mo&gt;&lt;/mover&gt;&lt;/mrow&gt;&lt;mo is=\"true\"&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;&lt;/span&gt;&lt;script type=\"math/mml\"&gt;&lt;math&gt;&lt;mrow is=\"true\"&gt;&lt;mo is=\"true\"&gt;(&lt;/mo&gt;&lt;mrow is=\"true\"&gt;&lt;mn is=\"true\"&gt;000&lt;/mn&gt;&lt;mover accent=\"true\" is=\"true\"&gt;&lt;mn is=\"true\"&gt;1&lt;/mn&gt;&lt;mo is=\"true\"&gt;¯&lt;/mo&gt;&lt;/mover&gt;&lt;/mrow&gt;&lt;mo is=\"true\"&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/script&gt;&lt;/span&gt; and Zn-ZnO&lt;span&gt;&lt;span style=\"\"&gt;&lt;/span&gt;&lt;span data-mathml='&lt;math xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow is=\"true\"&gt;&lt;mo is=\"true\"&gt;(&lt;/mo&gt;&lt;mn is=\"true\"&gt;0001&lt;/mn&gt;&lt;mo is=\"true\"&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"&gt;&lt;svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 2781 1196.3\" width=\"6.459ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;&lt;g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"&gt;&lt;g is=\"true\"&gt;&lt;g is=\"true\"&gt;&lt;use xlink:href=\"#MJMAIN-28\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;g is=\"true\" tra","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"33 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing resistance to hydrogen embrittlement in high-strength hot-press-forming steel sheets through Al-Si-Zn coating optimization","authors":"Seok-Hyun Hong ,&nbsp;Hyung-Jun Cho ,&nbsp;Selim Kim ,&nbsp;Sang Yoon Song ,&nbsp;Hyun Chung ,&nbsp;Suk-kyu Lee ,&nbsp;Sunghak Lee ,&nbsp;Seok Su Sohn ,&nbsp;Sung-Joon Kim","doi":"10.1016/j.actamat.2024.120527","DOIUrl":"10.1016/j.actamat.2024.120527","url":null,"abstract":"<div><div>This study addresses critical issues of hydrogen embrittlement (HE) and liquid metal embrittlement (LME) in Al-Si-coated and Zn-coated hot-press-forming (HPF) steel sheets, respectively, by proposing an innovative approach of incorporating (24–30) wt% Zn into the conventional Al-Si (AS) coating to mitigate HE issues while leveraging the absence of LME associated with Zn coating. To the best of the authors' knowledge, no other paper has considered this subject. The optimal Al-Si-Zn (ASZ) sheet formed a surface oxide layer and Zn-enriched zone, acting as local trap sites to reduce H intrusion, while the AS sheet lacked this zone, leading to continuous H intrusion. The ASZ sheet reached complete H emission in 4 weeks, whereas significant H remained in the AS sheet even after 4 weeks due to higher H intrusion. This result emphasizes the crucial role of Zn addition in impeding H diffusion and ensuring excellent resistance to HE. Bending angles at peak load, crucial for assessing bending and sheet forming properties, were adversely affected by diffusible H contents within the sheets. When austenitized at 900 °C for 3 min and then cooled to 800 °C for tensile testing, the ASZ sheet experienced abrupt premature fracture due to selective Zn diffusion from the liquid alloy to grain boundaries, inducing LME. However, prolonged austenitization to 6 min mitigated LME, with no expected issues on LME. These findings underscore the significance of the tailored Al-Si-Zn coating in enhancing resistance to HE, making it suitable for broad applications in high-strength HPF steel sheets.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120527"},"PeriodicalIF":8.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142563074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Standard deviation in maximum restoring force controls the intrinsic strength of face-centered cubic multi-principal element alloys","authors":"Fei Shuang ,&nbsp;Luca Laurenti ,&nbsp;Poulumi Dey","doi":"10.1016/j.actamat.2024.120508","DOIUrl":"10.1016/j.actamat.2024.120508","url":null,"abstract":"<div><div>In this study, we explore the mechanisms underlying the exceptional intrinsic strength of face-centered cubic (FCC) Multi-Principal Element Alloys (MPEAs) using a multifaceted approach. Our methods integrate atomistic simulations, informed by both embedded-atom model and neural network potentials, with first-principles calculations, stochastic Peierls-Nabarro (PN) modeling, and symbolic machine learning. We identify a consistent, robust linear correlation between the strength of MPEAs and the standard deviation of the maximum stacking-fault restoring force (<em>τ</em>_max,sd) across various potentials. This finding is substantiated by comparing the experimental strengths of Cantor alloys’ subsystems and Ni_62.5V_37.5 against <em>τ</em>_max,sd values from high-throughput first-principle calculations. Our theoretical insights are derived from integrating the stochastic Peierls-Nabarro model with a shearable precipitation hardening framework, demonstrating that lattice distortion alone does not directly enhance intrinsic strength. Instead, <em>τ</em>_max,sd emerges as a critical determinant, capable of boosting the strength of MPEAs by up to tenfold. Our analysis reveals the critical role of the exponential form of the PN model in achieving substantial strength improvement by transforming the Gaussian-like distribution of <em>τ</em>_max into an exponential-like distribution of local Peierls stress. Additionally, using an advanced symbolic machine learning technique, the sure independence screening and sparsifying operator (SISSO) method, we derive interpretable relationships between MPEA strength, elastic properties, and <em>τ</em>_max statistics, offering new insights into the design and optimization of advanced MPEAs. These findings highlight that the nonlinear physics and atomic fluctuations characterizing MPEAs not only underpin their unconventional intrinsic strength but also contribute to other complex properties such as sluggish diffusion and cocktail effect.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"282 ","pages":"Article 120508"},"PeriodicalIF":8.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slip transfer and crack initiation at grain and twin boundaries during strain-controlled fatigue of solution-hardened Ni-based alloys","authors":"I. Escobar-Moreno,&nbsp;E. Nieto-Valeiras,&nbsp;J. LLorca","doi":"10.1016/j.actamat.2024.120497","DOIUrl":"10.1016/j.actamat.2024.120497","url":null,"abstract":"<div><div>Slip transfer/blocking at grain and twin boundaries as well as preferential fatigue crack nucleation locations were studied in two solution-hardened Ni-based alloys (Inconel 600 and Hastelloy C276) deformed under strain-controlled, fully-reversed cyclic deformation in the low-cycle fatigue regime. Electron backscatter diffraction-based slip trace analysis was used to identify the active slip systems after interrupted fatigue tests. It was found that the Luster-Morris parameter <span><math><mrow><msup><mrow><mi>m</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>6</mn></mrow></math></span> was an accurate geometrical criteria to discriminate between slip transfer and blocking at grain and twin boundaries. Moreover, it was found that fatigue cracks initiation was always intergranular and cracks were nucleated at grain and twin boundaries when the slip transfer across was blocked. The probability of crack nucleation increased with the misorientation angle and was independent of the grain size. This behavior was associated with the development of stress concentrations at grain and twin boundaries as well as triple junctions in which slip was blocked and is different from previous reports on fatigue crack nucleation in Ni-based superalloys deformed, in which the slip system parallel to the TB in the parent grain was suitably oriented for slip. This contrast in the fatigue crack nucleation sites between both types of Ni alloys were attributed to the differences in the degree of strain localization and show how this factor controls damage nucleation in polycrystals.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120497"},"PeriodicalIF":8.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nb-doped coherent TiO2/LaAlO3 interfaces: Segregation mechanism and improved photocatalytic performance","authors":"Xiang Li ,&nbsp;Yixiao Jiang ,&nbsp;Qianqian Jin ,&nbsp;Fei Qin ,&nbsp;Tingting Yao ,&nbsp;Ang Tao ,&nbsp;Xuexi Yan ,&nbsp;Chunyang Gao ,&nbsp;Zhiqing Yang ,&nbsp;Chunlin Chen ,&nbsp;Gang Liu ,&nbsp;Xiu-Liang Ma ,&nbsp;Hengqiang Ye","doi":"10.1016/j.actamat.2024.120504","DOIUrl":"10.1016/j.actamat.2024.120504","url":null,"abstract":"<div><div>Elemental doping at coherent interfaces is very difficult and rarely used to improve the interfacial properties since coherent interfaces have low interfacial energies and lack open space for trapping dopant atoms. Exploring universally applicable strategies for elemental doping at coherent interfaces represents an important progress in interface science and engineering. In this study, Nb atoms are successfully doped at coherent (001) LaAlO₃/anatase-TiO₂ interfaces, which enhances greatly the efficiency of photocatalytic hydrogen production from water. Transmission electron microscopy investigations reveal that both LaO- terminated and AlO₂-terminated LaAlO₃/anatase-TiO₂ interfaces can trap two layers of Nb atoms, which accompanies with the formation of La vacancies between them. First-principles calculations suggest that Nb atoms segregate at the interfaces under the action of potential gradient, which increases significantly the strength of the built-in electric field in TiO₂, thereby facilitating the separation of photogenerated carriers and improving the photocatalytic performance. The H₂ production of the Nb doped coherent interface is about 4 times that of the pristine coherent interface. Since potential gradient widely exists at various interfaces including the coherent ones, elemental doping by potential gradient should be an universally applicable fabrication method for tuning the properties of interfaces and heterostructures.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"282 ","pages":"Article 120504"},"PeriodicalIF":8.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new approach to solid-state nucleation in kinetically-constrained systems","authors":"Christopher Hutchinson,&nbsp;Yves Brechet","doi":"10.1016/j.actamat.2024.120521","DOIUrl":"10.1016/j.actamat.2024.120521","url":null,"abstract":"<div><div>Nucleation is the first step of the phase transformations that we use to control the microstructures of engineering materials. The starting point for questions of nucleation is usually Classical Nucleation Theory (CNT) but for solid-state nucleation at low temperatures where atomic mobility is limited, such as in engineering alloys, CNT has not been very successful is quantitatively predicting nucleation. A strong assumption of CNT is that all thermally-induced stochastic fluctuations, no matter how far their compositions lie from the bulk alloy composition, are possible and that they become nuclei when a critical size determined from thermodynamics is reached.</div><div>Here we present a new and complementary model for solid-state nucleation. We consider the other extreme where atomic mobility is limited and thermally-induced stochastic clusters cannot form in the time scale relevant for a nucleation event. Instead, we consider the geometric clusters that are a statistical feature of any solution as the origin of the nuclei and present a simple model for the number of nuclei and their rate of ‘activation’. This new ‘geometric cluster’ model is shown to be able to successfully predict the competition in phase nucleation during the crystallization of a series of Al-Ni-Y metallic glass, predict the solvent trapping that is increasingly seen in solid-state nucleation and predict the peak number density of precipitates observed in Cu-Co and Fe-Cu alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120521"},"PeriodicalIF":8.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced reliability of Cu-Sn bonding through the microstructure evolution of nanotwinned copper","authors":"Xinyu Jin ,&nbsp;Huahan Li ,&nbsp;Yingying Sun ,&nbsp;Zhiqin Chen ,&nbsp;Peixin Chen ,&nbsp;Hongwei Su ,&nbsp;Ming Li ,&nbsp;Yunwen Wu","doi":"10.1016/j.actamat.2024.120524","DOIUrl":"10.1016/j.actamat.2024.120524","url":null,"abstract":"<div><div>Kirkendall voids are detrimental to the Cu-Sn bonding interface, causing the failure of the high-density package. Herein, the perpendicularly aligned nanotwinned Cu (p-ntCu) and the horizontally aligned nanotwinned Cu (h-ntCu) are prepared by controlling the electrodeposition procedure. The p-ntCu shows advantages both in fast-bonding process and in void suppression through the in-situ microstructure evolution. Compared with h-ntCu, the abundant perpendicularly aligned twin boundaries in p-ntCu provide fast interdiffusion paths to build a bonding interface. In the bonding process, p-ntCu grows to ultra-large-grained Cu with an average grain size of 6.68 μm. The reduced density of normal grain boundaries in p-ntCu lowers the Cu diffusion rate and contributes to more balanced interdiffusion at the bonding interface, which is confirmed by molecular dynamics simulation and kinetic calculations of intermetallic compound (IMC) growth. In addition, the low impurity content in p-ntCu further reduces the diffusion flux imbalance and limits the nucleation of Kirkendall vacancies. Consequently, the p-ntCu/Sn interface keeps void-free during 150 °C long-term thermal aging due to the synergistic effect of reduced grain-boundary diffusion and lower impurity content, which will be beneficial for achieving high-reliability Cu-Sn bonding.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"283 ","pages":"Article 120524"},"PeriodicalIF":8.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142542108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}