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金属顶刊双语导读丨Acta Mater. Vol.211,1 Jun. 2021(上)

2021-07-04 来源:GS_Metals

 

本期包含金属材料领域论文9,涵盖了马氏体、镁合金、增材制造等,国内科研单位包括上海交通大学等(通讯作者单位)。

 

Vol. 211 目录

1. A generally reliable model for composition-dependent lattice constants of substitutional solid solutions

置换型固溶体晶格常数随组分变化的普适模型

 

2. Accurate prediction of vacancy cluster structures and energetics in bcc transition metals

BCC过渡金属空位团簇结构与能量的精确预测

 

3. Frequency-dependent fatigue damage in polycrystalline copper analyzed by FIB tomography

多晶铜疲劳损伤随频率变化的FIB断层扫描研究

 

4. Factors controlling segregation tendency of solute Ti, Ag and Ta into different symmetrical tilt grain boundaries of tungsten: First-principles and experimental study

Ti、Ag、Ta等溶质元素在对称倾侧晶界偏聚的第一性原理计算与实验研究

 

5. Universal prediction of strain footprints via simulation, statistics, and machine learning: low-Σ grain boundaries

基于模拟、统计和机器学习方法识别低Σ晶界

 

6. Stacking-fault mediated plasticity and strengthening in lean, rare-earth free magnesium alloys

无稀土元素掺杂低合金化镁合金中层错介导的强塑性协同提高

 

7. The development of grain structure during additive manufacturing

增材制造过程中的晶粒结构演化研究

 

8. Fracture resistance of AlSi10Mg fabricated by laser powder bed fusion

激光粉末熔炼AlSi10Mg的抗断裂性能研究

 

9. Ultrafine-grained dual-phase maraging steel with high strength and excellent cryogenic toughness

高强度、高低温韧性超细晶双相马氏体时效钢研究

 

 

ACTA

Vol. 211,1 Jun. 2021, 116865

1. A generally reliable model for composition-dependent lattice constants of substitutional solid solutions

置换型固溶体晶格常数随组分变化的普适模型

 

Mingxu Wang, Hong Zhu, Gongji Yang, Jinfu Li, Lingti Kong

L. Kongkonglt@sjtu.edu.cn(上海交通大学)

https://doi.org/10.1016/j.actamat.2021.116865

 

摘要

固溶强化是一种提高材料性能的有效手段,其效果通常与晶格畸变密切相关,因此,准确描述晶格常数与固溶成分的关系对材料设计具有重要意义。而现有模型很难描述成分和晶格常数之间的非线性关系。本研究中,我们通过同时考虑尺寸效应和电子效应,提出了一个在虚拟晶体近似框架下的新模型。对于n元系统,模型以n元元素和基本性质参数作为输入,即可预测体系中任何成分固溶体的晶格常数。我们通过高通量第一性原理计算和实验数据对模型进行了验证,证明了我们的模型具有高可靠性和泛用性。此外,我们对模型的相关应用和局限性进行了讨论。该模型能够大大加深我们对材料成分-性能关系的理解

向上滑动阅览英文摘要

Solid solutioning has long been employed to improve the performance of enegineering materials, the degree of improvement generally correlates closely with the resultant lattice parameters. It is therefore of great importance for materials design to describe accurately the composition-dependent lattice constants of the solid solutions (SSs). However, existing models could hardly reproduce the usually non-linear relationship between the compositions and the lattice constants. Herein, we present a new model within the framework of virtual crystal approximation by taking into account both the size factor and the electronic effect. The model takes inputs as simple as the fundamental property parameters of the elementary substances and N referential SSs for an N-component system, and can then predict the lattice constant of SS with any composition within the system. Systematical validation using datasets obtained from high-throughput first-principles calculations and available experiments confirmed the high reliability and general applicability of our model for various substitutional SSs. Applications and limitations of the model as well as outlooks were also discussed. It is expected that this model will deepen the understanding of the relationship between the composition and the properties of materials.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116860

2. Accurate prediction of vacancy cluster structures and energetics in bcc transition metals

BCC过渡金属空位团簇结构与能量的精确预测

 

Jie Hou, Yu-Wei You, Xiang-Shan Kong, Jun Song, C.S. Liu

X.-S. Kongxskong@sdu.edu.cn(中科院固体物理研究所/山东大学)

J. Songjun.song2@mcgill.ca

https://doi.org/10.1016/j.actamat.2021.116860

 

摘要

空位团簇的结构和能量是金属缺陷演化中最重要的参数之一。然而,目前还没有可以准确确定空位团簇精细结构和能量的可靠方法。本研究中,我们采用第一性原理对BCC金属中空位团簇的稳定结构和能量进行了计算,证明了空位团簇的稳定结构可以通过最小化Wigner-Seitz区域来精确预测,并揭示了形成能与空位团簇Wigner-Seitz区域之间的线性关系。我们进一步建立了一个新物理模型来准确预测任意大小空位簇的稳定结构和能量学。模型得到了第一性原理计算和空位团簇退火实验的验证,且相比广泛使用的球面近似模型具有明显优势。本研究为空位团簇的形成演化提供了见解,对原子间作用势的分析具有重要意义,在预测和调控金属中的空位相关损伤方面迈出了关键一步

向上滑动阅览英文摘要

Knowledge on structures and energetics of vacancy clusters is fundamental to understand defect evolution in metals. Yet there remain no reliable methods able to determine essential structural details or to provide accurate assessment of energetics for general vacancy clusters. Here, we performed systematic first-principles investigations to examine stable structures and energetics of vacancy clusters in bcc metals, explicitly demonstrated the stable structures can be precisely determined by minimizing their Wigner-Seitz area, and revealed a linear relationship between formation energy and Wigner-Seitz area of vacancy clusters. We further developed a new physics-based model to accurately predict stable structures and energetics for arbitrary-sized vacancy clusters. This model was well validated by first-principles calculations and recent vacancy cluster annealing experiments, and showed distinct advantages over the widely used spherical approximation. The present work offers mechanistic insights that crucial for understanding vacancy cluster formation and evolution, provides crucial benchmarks for assessing empirical interatomic potentials, and enables a critical step towards predictive control and prevention of vacancy cluster related damage processes in structural metals.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116859

3. Frequency-dependent fatigue damage in polycrystalline copper analyzed by FIB tomography

多晶铜疲劳损伤随频率变化的FIB断层扫描研究

 

S. Fintová, I. Kuběna, A. Chlupová, M. Jambor, I. Šulák, Z. Chlup, J. Polák

S. Fintováfintova@ipm.cz

https://doi.org/10.1016/j.actamat.2021.116859

 

摘要

我们研究了多晶纯铜在4Hz-20kHz频率循环荷载下的疲劳性能。研究表明,随着频率增加,断裂循环周期增加。我们通过准静态和动态拉伸试验,从应变率敏感性的角度对以上现象进行了解释。我们首先使用SEM研究了不同应力幅度和频率下样品表面起伏的演化,发现表面形成了特征滑移带。在所有样品中,滑动带下方的主滑动平面周围都形成了孔洞。随后通过对FIB样品进行三维重构,获得了孔洞的分布形貌。我们发现孔洞分布和表面浮凸之间存在密切联系。粗糙的表面和表面下滑移平面附近的孔洞共同导致了疲劳裂纹的产生。我们从滑移带内空位聚集形成孔洞的角度,对循环应变下的应变率进行了分析

向上滑动阅览英文摘要

 

Pure polycrystalline copper has been subjected to cyclic loading with frequencies from 4 Hz to 20 kHz. With increasing frequency, the S-N curve was shifted to a higher number of cycles to fracture. Quasi-static and dynamic tensile tests were performed to identify the strain rate sensitivity corresponding to the increase of the cyclic frequency in order to explain the shift of the S-N curve with the frequency.

Surface relief evolution has been studied in specimens cycled with various stress amplitudes and frequencies. Scanning electron microscopy inspection of the surface and the perpendicular cuts produced by focused ion beam sectioning allowed characterizing the surface relief and internal structure of the individual specimens subjected to cycling. Characteristic types of slip bands were found. In all cases, cavities formed in or around the primary slip plane below the slip markings. Focused ion beam slicing and image recording with subsequent 3D reconstruction allowed obtaining the distribution of cavities below the slip markings. A close relation was established between the distribution of cavities and resulting surface relief. Formation of cavities in the slip band led to the development of extrusions and in some cases also to tiny intrusions. Both rough surface relief and the cavity distribution below the surface along the slip plane contributed to the initiation of the fatigue cracks. Localized cyclic straining with a high strain rate has been analyzed in terms of vacancy generation within the slip band leading to cavity formation

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ACTA

Vol. 211,1 Jun. 2021, 116868

4. Factors controlling segregation tendency of solute Ti, Ag and Ta into different symmetrical tilt grain boundaries of tungsten: First-principles and experimental study

TiAgTa等溶质元素在对称倾侧晶界偏聚的第一性原理计算与实验研究

 

Ahmed Tamer AlMotasem, Teodor Huminiuc, Tomas Polcar

A.T. AlMotasema.almotasem@aun.edu.eg, ahmed.alasqalani@soton.ac.uk

https://doi.org/10.1016/j.actamat.2021.116868

 

摘要

实验研究表明,晶界(GB)偏聚对晶体材料的热稳定性和强度具有重要影响。本研究中,我们利用密度泛函理论(DFT)计算了W的小/大角度对称倾斜晶界(STGBs)TiAgTa等溶质原子的偏聚,并用TEM实验进行了验证。我们发现在小角度对称倾侧晶界处,不发生TiTa元素的偏聚;而这两种元素在大角度对称倾侧晶界核心处则表现出一定的偏聚倾向。相比之下,Ag更容易在晶界平面内及其周围偏聚。我们计算了力学效应和电子效应对固溶元素能量的贡献,发现电子的影响占主导地位。此外,我们利用局域态密度函数(PDOS)分析了溶质原子和W原子d轨道电子的作用。发现,在Ta固溶的情况下,大量d轨道电子发生杂化,对W-Ta键的稳定起重要作用。另一方面,W-Ti键各向异性的特点也有助于周围W原子的稳定。电荷转移分析表明,电子从TiTa原子转移至W原子。与电负性规则相反,Ag原子从邻近的W原子获得电子,显著的s-s杂化可以有效解释Ag原子在晶界处的偏聚

向上滑动阅览英文摘要

In previous reports, experimental studies have shown that both thermal stability and strength can be controlled by grain boundary (GB) segregation. In this study, we investigate the segregation behavior of solute (Ti, Ag and Ta) atoms to low/high-angle symmetric tilt grain boundaries (STGBs) of W using density functional theory (DFT) calculations and supported by TEM experiments. We found no segregation preference for Ti or Ta at low-angle STGBs; however, they exhibit a slight segregation tendency to the core of high-angle STGBs. In contrast, Ag is more prone to segregate in and all around the GB plane. We estimated the mechanical and electronic contributions to solution energy and found that the electronic contribution is dominant. Furthermore, the role of d−valence electrons of solute and W atoms, was analyzed using the local density of states (PDOS). We found that substantial d−valence electrons hybridization in the case of Ta plays an important role in stabilizing W-Ta bonds, while the anisotropic nature of W-Ti bond contributes to stabilize surrounding W atoms. Charge transfer analysis revealed that Ti and Ta lose electrons to W atoms. Contrary to the electronegativity rule, Ag atoms gain charge from neighboring W atoms and excellent s−s hybridization may explain the increased GB segregation of Ag atoms.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116850

5. Universal prediction of strain footprints via simulation, statistics, and machine learning: low-Σ grain boundaries

基于模拟、统计和机器学习方法识别Σ晶界

 

Matthew T. Curnan, Wissam A. Saidi, Judith C. Yang, Jeong Woo Han

J.W. Hanjwhan@postech.ac.kr

https://doi.org/10.1016/j.actamat.2021.116850

 

摘要

人们常常通过界面对材料的催化性能进行综合调控。由于金属晶界(GBs)呈无序结构,因此具有巨大的调控潜力。虽然实验表明晶界的催化路径取决于位错的弹性应变,但晶界的原子结构和催化能力的能量起源尚不清楚。在以往通过宏观自由度定义亚稳态晶界的模型中,我们往往无法对重晶格点位模型预测的低Σ晶界进行准确识别。因此在本研究中,我们发展出了一种结构-能量关系,能够将原子性质变化与物理模型联系起来,从而从常规大角晶界中区分出异常晶界。这项工作基于三个微观自由度构建晶界的弹性响应,通过直接统计方法对晶界进行区分。这一方法可以成功地从大角晶界中区分出低Σ晶界。我们基于亚稳态晶界和相应的弹性响应,构建了机器学习分类算法。验证表明,其性能优于以往的分类模型

向上滑动阅览英文摘要

 

Interface engineering usually imposes a trade-off between catalytic activity, product selectivity, and property tunability, facilitating multiple product yields. Due to their structural disorder, metal grain boundaries (GBs) can be constructed to satisfy all of these conditions. Though experiments show GB catalytic footprints are determined by dislocation-induced elastic strain, the atomistic structural and energetic origins of GB catalytic performance are not currently known. In former models solely reviewing metastable GBs defined by macroscopic degrees of freedom (DOFs), exceptional low-Σ GBs anticipated by the coincident site lattice model cannot be consistently discerned. Herein, a structure-energy correlation linking changes in atomistic properties to physical models is developed, distinguishing exceptional GBs from unexceptional high-angle GBs over structural DOFs. This work constructs particular GB elastic responses by varying three microscopic DOFs, comparing low-Σ distinguished and other GB responses via a directed statistical approach. Such elastic properties successfully distinguish low-Σ GBs from high-angle grain boundaries (HAGBs) by their strain-related footprints without failure of a single unique GB structure and composition combination. A priori application of machine learning classification is completed using metastable GB and elastic response related properties. This classification not only validates distinguished strain footprints, but also identifies GB subgroups with footprints unexpected by former models.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116877

6. Stacking-fault mediated plasticity and strengthening in lean, rare-earth free magnesium alloys

无稀土元素掺杂低合金化镁合金中层错介导的强塑性协同提高

 

I. Basu, M. Chen, J. Wheeler, R.E. Schäublin, J.F. Löffler

I. Basuindranil.basu@mat.ethz.ch

J.F. Löfflerjoerg.loeffler@mat.ethz.ch

https://doi.org/10.1016/j.actamat.2021.116877

 

摘要

我们在室温下,对ZX10合金(即少量添加了1wt.%Zn0.3wt.%Ca的镁合金)和纯镁进行了微柱压痕试验。我们制备了两种不同取向的单晶微柱,分别用于激活c轴方向的拉伸和压缩。在两种加载条件下,与纯Mg相比,ZX10的强度增加了22.5倍,且塑性也增强。背散电子和透射电子表征表明,拉伸条件下,ZX10变形是通过孪晶发生的,在较高的应力水平下,基底滑移和非基滑移被均匀激活。而纯镁则通过拉伸孪晶和基底滑动发生变形。压缩条件下,纯Mg通过基底位错介导的大规模滑移发生变形,而ZX10中则发生a位错和c+a位错的双重激活。锌和钙的添加改变了层错能,从而导致材料了材料强度和塑性的协同增强。研究证明了少量添加锌和钙对激活Mg合金变形机制有益,对无稀土元素添加的高强高塑镁合金结构材料和生物材料的设计具有重要意义

向上滑动阅览英文摘要

A magnesium alloy with lean additions of Zn (1 wt.%) and Ca (0.3 wt.%), ZX10, and pure Mg were subjected to orientation-dependent micropillar indentation tests at ambient temperature. Single-crystalline micropillars of two different orientations were fabricated to activate extension and compression along the c-axis, respectively. For both loading conditions, ZX10 exhibits a strengthening increment by a factor of 2 to 2.5 compared to pure Mg along with plasticity enhancement. Correlative transmission electron back-scattered diffraction and transmission electron microscopy reveal that deformation in ZX10 proceeds by deformation twinning under c-axis extension, generating homogeneous activation of basal and non-basal slip at higher strains. In contrast, pure Mg displays deformation through tension twinning and basal slip. Pure Mg under c-axis compression deforms by basal dislocation-mediated massive sliding, while ZX10 reveals dual activation of basal a and pyramidal c+a dislocations. Mechanistically, the minute additions of Zn and Ca solutes modify the intrinsic stacking-fault energy, which accounts for the simultaneous strengthening and ductility enhancement. These findings highlight the beneficial impact of dilute additions of Zn and Ca in activating novel deformation pathways that are critical for designing rare-earth (RE) free high-strength, highly ductile magnesium alloys for structural and biomedical applications.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116862

7. The development of grain structure during additive manufacturing

增材制造过程中的晶粒结构演化研究

 

Alexander F. Chadwick, Peter W. Voorhees

P.W. Voorheesp-voorhees@northwestern.edu

https://doi.org/10.1016/j.actamat.2021.116862

 

摘要

合金增材制造过程中往往会形成复杂的显微组织,通常包括由现有晶粒外延生长得到的长柱状晶粒。在本研究中,我们建立了一个相场模型,模拟固液界面移动足够快,成分变化可忽略不计的情况下,316L不锈钢的凝固过程。通过与运动的激光源热场耦合,模型模拟得到了晶粒在熔池周围凝固的轨迹。我们通过三维模拟研究了界面动力学各向异性对凝固组织影响。通过定性和定量分析,我们发现沿激光移动轨迹中心处,动力学各向异性的影响最大。凝固早期晶粒的形貌主要受熔池形状控制

向上滑动阅览英文摘要

Additive manufacturing of structural alloys results in the formation of complex microstructures, often with long, columnar grains that grow epitaxially from existing grains. A phase-field modeling framework is presented that considers solidification along a single track of 316L stainless steel in a regime where the solid-liquid interface is moving sufficiently fast that there is absolute interfacial stability with negligible composition variations. By coupling to a thermal field of a moving laser source, the model captures the trajectory of grains solidifying around a melt pool. The effect of interfacial kinetic anisotropy on the predicted as-solidified microstructures is examined through three-dimensional simulations. Through a combination of qualitative and quantitative analyses, we find that kinetic anisotropy has the largest impact along the center of the laser track and that the grain morphology in the early stages of solidification is predominantly due to the shape of the melt pool.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116869

8. Fracture resistance of AlSi10Mg fabricated by laser powder bed fusion

激光粉末熔炼AlSi10Mg的抗断裂性能研究

 

Moses J. Paul, Qian Liu, James P. Best, Xiaopeng Li, Jamie J. Kruzic, Upadrasta Ramamurty, Bernd Gludovatz

B. Gludovatzb.gludovatz@unsw.edu.au

https://doi.org/10.1016/j.actamat.2021.116869

 

摘要

激光粉末熔炼(LPBF)制备的AlSi10Mg中,快速冷却导致的组织细化和和熔池诱导形成介观组织使得材料具有优异的强度和断裂韧性。深入了解加工条件对组织的影响能够更好地帮助我们调控材料性能,特别是断裂抗性。为此,我们对以不同层厚、窗口间距和扫描策略加工的AlSi10Mg合金的不同取向抗裂曲线(R曲线)进行了分析,并将其与晶粒尺寸、取向、织构、胞结构形貌、熔池分布等组织特征建立了联系。结果表明,材料的拉伸性能和断裂韧性都具有较强的各向异性,其中,强度主要受层厚和窗口间调控,而断裂韧性主要受扫描策调控。就拉伸性能而言,熔池边界与加载方向相对关系的不同导致了延伸率的各向异性,而强度主要有晶粒尺寸和胞结构控制。而就断裂韧性而言,熔池形貌是影响材料失效的主要因素,因此断裂韧性主要受扫描策调控。进一步研究表明,尽管R曲线具有明显各向异性,但LPBF制备AlSi10Mg中独特的组织还是使得这种材料的耐损伤性能优于铸造合金

向上滑动阅览英文摘要

The combination of refined microstructures (induced by rapid cooling) and melt pool-induced mesostructures in AlSi10Mg fabricated using laser powder bed fusion (LPBF) – a widely used additive manufacturing technique – impart high strength and fracture toughness. Further exploitation of such property combinations requires a detailed understanding of how the processing conditions control the micro- and mesostructures and, in turn, the mechanical performance, especially regarding fracture resistance. Towards this end, the crack resistance curve (R-curve) behavior in different orientations of LPBF-fabricated AlSi10Mg alloys processed with different layer thickness, hatch spacing, and scan strategies was evaluated and correlated with micro- and mesostructural features such as grain size and grain orientation, texture, cell morphology, and melt pool arrangement. Results show a strong anisotropy in both tensile stress-strain behavior and fracture toughness with layer thickness and hatch spacing controlling strength and scan strategy dictating fracture resistance. In terms of tensile stress-strain behavior, the arrangement of melt pool boundaries with respect to loading direction results in anisotropy in ductility whereas strength is controlled by grain size and cellular structure. In case of fracture toughness, measurements show that failure is dominated primarily by melt pool morphology and hence the mesostructure that is controlled by scan strategy. They furthermore reveal, that, despite the pronounced anisotropy in the R-curve behavior the presence of such mesostructure enables a level of damage-tolerance in AlSi10Mg that cannot be achieved in a cast alloy.

 

 

ACTA

Vol. 211,1 Jun. 2021, 116878

9. Ultrafine-grained dual-phase maraging steel with high strength and excellent cryogenic toughness

高强度、高低温韧性超细晶双相马氏体时效钢研究

 

Honglin Zhang, Mingyue Sun, Yuxuan Liu, Dongping Ma, Bin Xu, Mingxin Huang, Dianzhong Li, Yiyi Li

M. Sunmysun@imr.ac.cn(沈阳金属所)

M. Huangmxhuang@hku.hk(香港大学)

https://doi.org/10.1016/j.actamat.2021.116878

 

摘要

我们提出了一种新的热处理工艺,即低温固溶和500°C过时效处理,制备得到了具有超细马氏体(α′)和奥氏体(γ)双相组织的高强、高低温韧性钢铁材料。与传统工艺制备得到的的全马氏体时效钢相比,材料的低温冲击功增加了12倍(77K~140J),而屈服强度没有明显降低。在500°C过时效过程中,马氏体逆转变形成大量超细晶奥氏体(体积分数~50%)。令人惊讶的是,在拥有如此高比例奥氏体的情况下,材料的屈服强度能够与传统马氏体时效钢相当。在马氏体和奥氏体两相中都存在高密度纳米析出,因此两相都具有很高的强度,纳米压痕试验证实了这一点。两相中高密度的纳米析出确保了材料的高强度。而材料优异的低温韧性主要源于:(i)大量FCC结构的奥氏体本身的韧性较高;(ii)冲击过程中奥氏体发生TRIP效应;(iii)马氏体和奥氏体的晶粒细化。这一热处理工艺为低温应用的大型工程部件制备提供了一种有效的解决方案。需要注意的是,为保证部件性能均匀,需要较长的热处理时间

向上滑动阅览英文摘要

A novel heat treatment route consisting of a low-temperature solution followed by an over-aging treatment at 500 °C is proposed to develop a high-strength, high-cryogenic-toughness maraging steel by forming an ultrafine-grained martensite (α′) and austenite (γ) dual-phase microstructure. Compared to the same maraging steel subjected to the conventional heat treatment with a mostly martensitic microstructure, the present dual-phase microstructure offers a remarkable increase by 12 times of cryogenic impact energy (~140 J at 77 K), while the yield strength is not reduced obviously. A large amount of ultrafine-grained austenite (about 50% volume fraction) are formed in the present steel due to the reversed transformation of martensite to austenite during the over-aging process at 500 °C. It is surprised that the present steel with such a high fraction of austenite still possesses a high yield strength comparable to the conventional maraging steel with a mostly martensitic microstructure. Intensive nanoprecipitates are found not only in martensite but also in austenite phases, indicating both phases have high strength. This is confirmed by nanoindentation test, showing similar hardness values in both martensite and austenite phases. Such intensive nanoprecipitates in both phases ensure the high yield strength of the present steel. The excellent cryogenic toughness of the present steel mainly origins from: (i) the pronounced amount of reversed austenite that are intrinsically tough due to their face-centered cubic (fcc) structure; (ii) transformation-induced plasticity (TRIP) toughening as some austenite grains transforming to martensite during impact test; (iii) the ultrafine-grained structure of both martensite and austenite phases. The present heat treatment route offers a potential solution for processing large engineering components for cryogenic application that require a long heat treatment duration to achieving uniform mechanical properties in the components.