Transformation Boundary Research Articles

On the martensitic phase transformation and grain boundary character evolution in laser powder bed fusion 17-4 precipitation hardened stainless steel

Abstract Laser powder bed fusion (L-PBF) of 17-4 precipitate hardened (PH) stainless steel is well-known for its significant variations in reported microstructures. While recent research has provided better understanding of the phase transformation pathways leading to as-built microstructures of $$\delta$$ δ -ferrite, martensite, and/or austenite, reproducible and fully martensitic microstructures would be more desirable to provide strength and age-hardening potential. However, the understanding of the martensitic phase transformation as a function of 17-4 PH powder feedstock and L-PBF route remains limited. We aim to fill this gap by comparing builds from two processing routes with different powder feedstocks and processing parameters. As-built and heat treated (1 h at 1040 °C followed by water quenching) conditions are considered. We reveal the link between the parent austenite grain size (PAGS) and the resulting martensite microstructure. A detailed five-parameter characterization of interfaces shows that a smaller PAGS results in improved grain boundary connectivity and higher length fractions of 60°/[1 1 $$\overline{1 }$$ 1 ¯ ] and 10.5°/[0 1 1] intervariant boundaries in the martensite. Computational material science demonstrates the link between the processing parameters and composition with microstructural variations and development. Our results are broadly applicable to steel L-PBF, underpinning that refinement of martensite will improve the grain boundary network and selection of desirable intervariants. This is expected to impact material properties such as toughness, strength, intergranular corrosion, cracking, slip, and the segregation of impurities. Graphical abstract

Digital transformation and firm boundary reshaping: based on the dispersion of subsidiaries †

Digital transformation and firm boundary reshaping: based on the dispersion of subsidiaries ^†

Populism and Anti-Populism in Climate Politics: Conflict Line, Contingent Relation, or Tacit Alliance in Climate Obstruction?

AbstractDenial and far-right populism are regularly blamed for the inability of liberal democracies in the Global North to address climate change properly. But what is the nexus of populism and climate obstruction? In this article, I explore how ideational and discursive approaches to populism illuminate mechanisms of climate obstruction. While ideational approaches erroneously imply that there is a line of climate political conflict between “bad” populism and “good” anti-populism, discursive approaches suggest a contingent and relational character of populism, anti-populism, and climate obstruction. They not only enable raising awareness of the strategic–authoritarian character of far-right obstruction and the prevalence of obstruction beyond the far right but also prompt that anti-populist responses qua anti-populism contribute to obstruction by depoliticising climate politics. Eco-populist responses to obstruction that feature a political–strategic proximity to discursive approaches to populism, however, overlook an unresolved tension between agendas of inclusion via economic growth and agendas of ecological limitation. By ignoring this tension, they fail to capture societal boundaries of transformation, and they spread unwarranted strategies to break through climate obstruction politically. Therefore, I argue that instead of establishing a conflict line or a contingent relation, far-right obstruction, anti-populist, and eco-populist responses result in a tacit alliance in climate obstruction. To overcome this deadlock, I suggest research on (far-right) climate obstruction to focus on multiple entanglements of authoritarian defences of an unsustainable and imperial mode of living.

Digital transformation: The geopolitical-organizational nexus

This special issue aimed to attract articles situating digital transformation in the geopolitical-organizational nexus. Unlike innovation and change panaceas (or fads) like business process reengineering (BPR) which became popular in the 1990s, digital transformation is a multi-level concept. Extending beyond the redesign of organizational and business processes, the analytical boundaries of digital transformation include ecosystems, organizational networks, business and operational processes, organizational identities, governance structures, and quality/cost dynamics. However, the extant literature on digital transformation continues to use the organization as the primary unit of analysis. Definitions of digital transformation vary widely, with some not dissimilar to the BPR era. The papers included in this special issue provide analytical and empirical examples on the pervasive effects from contemporary digital technology for society, organizations, and citizens. Future work which isolates the digital technology artefact would benefit from further refinement of the digital transformation concept. A starting point is to revisit the digital technology evolution over past decades which reveal the inflection points of technological change, specifically for mainframes, PCs, and the Internet. Such analysis will increase our understanding and contextualization of past panaceas like BPR for generating new insights on how digital technologies are front and center in debates on digital transformation.

Identifying Rare Events in Quantum Molecular Dynamics of Nanomaterials with Outlier Detection Indices.

Nanoscale and condensed matter systems evolve on multiple length- and time-scales, and rare events such as local phase transformation, ion segregation, defect migration, interface reconstruction, and grain boundary sliding can have a profound influence on material properties. We demonstrate how outlier detection indices can be used to identify rare events in machine-learning based, high-dimensional molecular dynamics (MD) simulations. Designed to order data-points from typical to untypical, the indices enable one to capture atomic events that are hard to detect otherwise. We demonstrate the approach with a nanosecond MD simulation of a grain boundary in a metal halide perovskite that is extensively studied for solar energy and optoelectronic applications. The method captures the initial grain boundary sliding and a spontaneous fluctuation half a nanosecond later, both events giving rise to persistent deep electronic trap states that impact charge carrier lifetime and transport and material performance. The approach offers a generalizable and simple method for identifying outlier events in complex condensed matter, molecular, and nanoscale systems.

Heterogeneous‐Structured Refractory High‐Entropy Alloys: A Review of State‐of‐the‐Art Developments and Trends

AbstractRefractory high‐entropy alloys (RHEAs) inspire the development of novel high‐temperature structural materials due to their outstanding resistance to softening and phase stability at elevated temperatures. However, they struggle to simultaneously achieve high‐temperature strength and room‐temperature ductility, while exhibiting insufficient room‐temperature strain hardening capability. Heterogeneous structure strengthening possesses a unique plastic self‐coordinated ability, which can effectively maintain strain hardening rate to achieve an excellent combination of strength and ductility. Benefiting from slow atomic diffusion, severe lattice distortion, and broad compositional design space, RHEAs with heterogeneous structures can be prepared from both chemical composition and interface structure perspectives. Chemical composition heterogeneity primarily focuses on fluctuations of alloying elements at the nanoscale, along with the formation of heterogeneous precipitates and unique lamellar eutectic structures. While, interface structure heterogeneity manifests in the activation of phase transformation and twin boundaries within grains, along with the formation of grains of vastly different sizes. The trend in RHEAs development is toward structural‐functional integration. Heterogeneous structures can also optimize functional properties, such as irradiation resistance, biomedical properties, and high‐temperature softening resistance of RHEAs. Finally, a brief outlook is provided on the future development direction of heterogeneous structure RHEAs.

Kinetics of the α → γ′ stress-induced martensitic transformation in a Fe–Mn–Al–Ni shape memory bicrystal

The Fe–Mn–Al–Ni pseudoelastic system has garnered interest for diverse engineering applications owing to its promising characteristics. The poor pseudoelasticity in polycrystals is generally attributed to activation of new martensite variants and the high density of dislocations close to austenite/martensite interface. High-energy synchrotron X-ray diffraction and microscopy studies on a Fe–Mn–Al–Ni bicrystal reveal the sequence of transformation, deformation mechanisms, and grain boundary effects on martensite nucleation, shedding light on its limited pseudoelasticity in polycrystalline configurations. The results highlight challenges in achieving pseudoelasticity in polycrystalline configurations due to disparities in deformation between grains and at grain boundaries.

ON THE ONTOLOGICAL PURPOSE OF MAN

The position is substantiated that the possibility of overcoming chaos in the value sphere and the infinity of the processes of “revaluation of values” is associated with the search and acquisition of a person’s existential purpose. If in religious teachings the processes of transcendence, movement towards the “super-rational” and “supernatural” act as a condition for the formation of absolute values, then in philosophy different types of transcendence are considered. In the modern situation, in the conditions of the “struggle against metaphysics,” it becomes relevant not only to determine meaning and significance, but also to substantiate the right to the existence of the transcendent. At the same time, it is shown that the contradictions of the rapidly developing, high-tech world are the basis for searching for ways to reach the transcendent. The concept of the transcendent is explicated in the process of considering eternal philosophical problems, such as: the search for the integrity of the world; defining the boundaries of knowledge and transformation of reality; man’s acquisition of his own existence. It is shown that the fight against various kinds of “centrisms” leads to the formation of a new integrity, the basis of which is permanent variability and multidirectionality. The success of goal-oriented rational activity ultimately leads to the formation of such problems, the overcoming of which is possible only if one goes beyond the limits of empirical reality. The value of thought lies not in the fact that it reflects the objective world, but in the possibility of a person introducing personal, original things into the world he describes. Consequently, both in religion and in philosophy, a person is endowed with an “ontological purpose”, and the question of gaining/giving up the search for being is in the horizon of his (man’s) decisions. It is concluded that without access to the transcendental, the search for personal existence, value foundations, and cognitive truths is impossible, since all forms of activity carried out within the phenomenal world will lead to stagnation. The transition from phenomenal to noumenal being is necessary in order to set a different hierarchy, form other evaluation criteria and methods of systematization.

How does business environment affect firm digital transformation: A fsQCA study based on Chinese manufacturing firms

Digital transformation can improve firms' competitive advantages and contribute to regional economic development. The question of how to enhance the business environment to facilitate and encourage firm digital transformation emerges as a crucial area of inquiry. To explore the relationship between city-level business environment and firm digital transformation, we conducted configuration analysis based on a sample of 3088 manufacturing firms across 240 Chinese cities in year 2022. Based on results, we identified three distinct business environments, consisting of both detrimental and favorable factors, that can promote firm digital transformation. Thereinto, limited public resources, a shortage of human resources, and an underdeveloped market environment work that prompt firms' motivation of digital transformation, since the negative consequences stemming from those limitations can be mitigated by digital transformation. Meanwhile, a conducive innovation environment, significant financial development, a favorable legal environment, and a supportive political environment serve as advantageous factors that amplify firms' willingness to embrace digital transformation, since they mitigate costs and risks associated with digital transformation. Our study expands the theoretical boundaries of digital transformation, and provides valuable insights for government to optimize business environments to support firms’ digital transformation.

Oil-Water Two-Phase Flow with Three Different Crude Oils: Flow Structure, Droplet Size and Viscosity

The study focuses on the flow patterns and pressure drop characteristics of three crude oils and water in a horizontal pipe. The experimental results showed that the transformation boundary of the flow pattern and phase inversion water fraction were related to the flow parameters. Comparing the three oils, it was found that the viscosity and composition of the oil also significantly influence the flow performance, which can be explained by the adsorption properties of the asphaltenes at the oil-water interface. In particular, the droplet size in water-in-oil dispersion flow was observed and measured. It showed that the water droplet size decreased with the increase of oil viscosity, the decrease of water content, the drop of temperature, and the growth of mixing velocity, probably due to higher shear stress and lower frequency of collision and coalescence between droplets. The apparent viscosity of water-in-oil emulsions was calculated by the rheological model, and the qualitative relation between flow parameters and interfacial area concentration on apparent viscosity was obtained. Taking the influence of interfacial area concentration into consideration, a simple and accurate viscosity model was established based on dimensional analysis, which is of great significance for process design in gathering and transportation systems.

SCTBEM: A scaled coordinate transformation boundary element method with 99-line MATLAB code for solving Poisson's equation

This study introduces the scaled coordinate transformation boundary element method (SCTBEM), a novel boundary-type method for solving three-dimensional potential problems. To apply the BEM to complex problems, it is common practice to use the fundamental solution corresponding to the partial governing equation operator to establish the integral equation. However, this approach introduces the domain integral, which may jeopardize the dimensionality reduction advantages of BEM. To preserve the benefits of dimensionality reduction, this study proposes a novel domain integral transformation method named SCT. The SCT is purely a mathematical operation that does not rely on a particular solution of the operators, which requires only discretization on the surface of the structure while remaining analytical in the radial direction. An even more significant advantage is that the lower-order singularity can be eliminated by the coordinate translation technique. To facilitate the wider adoption of BEM, the authors present an open-source 99-line MATLAB code. Numerical results demonstrate that the SCTBEM exhibits high numerical accuracy even when dealing with complex models.

Proceedings of the Round Table "Cyborgization: New Challenges for the Modern Governance System" (October 2024, MGIMO, Moscow)

The article presents an analysis of the round table "Cyborgization: New Challenges for Modern Management Systems" held at MGIMO in October 2024. The event brought together leading Russian and international experts from various scientific fields for an interdisciplinary discussion on the merger of human and technological aspects. Key aspects of cyborgization were examined in the context of medicine, education, cybersecurity, psychotherapy, and social robotics. Special attention was paid to ethical issues of technology implementation, regulation of cyborgization processes, and determining acceptable boundaries of human technological modification. Results of practical experience in applying neurotechnologies, bionic prosthetics, and artificial intelligence systems were presented. Culture-specific features of new technology perception in different countries were analyzed. The necessity of developing a balanced approach to defining the boundaries of human technological transformation and the degree of recognition of cyborgized entities' subjectivity was formulated.

Can digital transformation improve the quality of enterprise innovation in China?

PurposeDigital transformation and innovation-driven development have become an international consensus. The purpose of this paper is to examine the effects of relationships, mechanisms and economic consequences between digital transformation and enterprise innovation quality in order to provide a benchmark for developing countries to implement digital transformation strategies and innovation-driven strategies and provide a major support for economic recovery in the post-coronavirus disease 2019 (COVID-19) era.Design/methodology/approachUsing microdata from A-share listed enterprises in Shanghai and Shenzhen from 2010 to 2021, this study examines the relationship between digital transformation and enterprise innovation quality and further reveals the internal logic and economic consequences of digital transformation to improve enterprise innovation quality through the mediating effect and moderating effect models.FindingsThe results demonstrate that digital transformation is beneficial for improving enterprise innovation quality. The heterogeneity test demonstrates that digital transformation has a larger effect on improving enterprise innovation quality in non-state-owned enterprises and eastern enterprises in China. The mechanism test demonstrates that digital transformation can improve enterprise innovation quality by improving internal control quality and analyst attention. Furthermore, with the increase in enterprise innovation inputs, digital transformation plays a significantly stronger role in improving enterprise innovation quality. The extended analysis demonstrates that digital transformation can significantly improve enterprise financial performance by improving innovation quality.Research limitations/implicationsFirst, the construction of the core explanatory variable digital transformation index in this study is based on the Python data analysis software, which calculates the frequency of digital transformation in the text of the business situation analysis portion of the annual report of the listed companies and then obtains the degree of digital transformation of the company in this year. There may be some deviation from the degree of digital transformation in the actual production and operation of enterprises. Second, in addition to internal control quality and analyst attention, are there other mediating mechanisms for the impact of digital transformation on the quality of enterprise innovation? Third, whether the moderating effect of innovation input on digital transformation and innovation quality is related to human capital factors of the research and development (R&D) team, such as the technical background of R&D personnel, etc.Originality/valueThis study enriches the relevant theories of digital transformation and broadens the research boundaries of digital transformation and enterprise innovation. This study's result provides an empirical basis for enterprises to improve enterprise innovation quality and financial performance from the perspective of digital transformation at the micro level and points out specific practical directions, combining theory with practice.

Framework for a chemo‐mechanical model of the breathing effect in lithium–silicon batteries

AbstractWe present a chemo‐mechanical finite element method model for the breathing effect of the silicon anode during lithiation and delithiation. The model is based on the framework for gradient extended standard dissipative solids. It couples diffusion of lithium ions, phase transformation with a moving phase boundary, and the related volume changes, which lead to mechanical stresses in the material. The driving force for diffusion is given by the gradient of the electrochemical potential. Phase transformation and phase boundary movement are described by the Allen–Cahn equation in combination with a constrained double obstacle potential. To shift the constraint from the nodes to the Gauss points, the model makes use of the micromorphic approach.

Construction of Digital Transformation Capability of Manufacturing Enterprises: Qualitative Meta-Analysis Based on Current Research

Competitive advantage in enterprises can be substantially enhanced by the strategic deployment of digital transformation capabilities, which can be considered as distinctive resources. Within the domain of manufacturing enterprises, the discernment and classification of the structural dimensions inherent in digital transformation capabilities can serve as a pivotal factor in facilitating a more adaptable and seamless progression through the digital transformation journey. In pursuit of this objective, 22 typical manufacturing enterprises are selected as data samples, and a four-dimensional digital transformation capability system is constructed through the processes of excerpt, coding, classification, reliability and validity, etc. Combined with the view of capability hierarchy, a three-level capability structure model of digital transformation capability is constructed. The results show that digital transformation capability includes digital technology capability, digital operation capability, digital organization capability and digital strategic capability, and it is found that there is a hierarchical relationship among the capabilities of each dimension. The research findings have extended the theoretical boundaries of digital transformation, augmented the applicability scenarios of dynamic capability theory, and established a foundational framework for future empirical investigations into the digital capabilities of manufacturing enterprises.

Назначение рациональных режимов электроэрозионной обработки деталей из титанового сплава ВТ5 на основе решения тепловой задачи о перемещении границы фазового превращения материала

The paper presents results of theoretical studies of the VT5 titanium alloy machinability by the electrodischarge machining method based on solving the thermal problem of the material phase transformation boundary displacement (Stefan problem). It proposes a method for determining parameters of electrical pulses for the VT5 alloy electrodischarge machining in order to increase the process productivity; recommendations are provided for that purpose. Density of the heat flux and its duration were determined necessary for implementation of the VT5 alloy electrodischarge machining process. Dependences were established of the minimum value of the heat flux pulse duration, when the VT5 alloy electrodischarge machining process was possible, and of maximum value of the heat flux pulse duration ensuring maximum removal of the VT5 alloy from the workpiece in one pulse, on the heat flux density. It is shown that for the maximum productivity of the VT5 alloy electrodischarge machining at the heat flux density used, it is necessary to assign effective duration of such a flux. Dependences of the heat flux effective duration on its density were established. Besides, to assign rational modes of VT5 ally electrodischarge machining, relationships were established and provided between the VT5 alloy machinability curves (dependences of the material penetration depth on the pulse duration) and other materials, including those for which rational modes are currently defined

Anomalous effect of nitrogen flow ratio on mechanical properties of NbMoTaW:(N,O) medium entropy alloy films

In this work, nanocrystalline NbMoTaW:(N,O) thin films were prepared by magnetron sputtering. The effect of nitrogen flow ratio [RNN2/(N2 + Ar)] ranging from 0 to 0.5 on the microstructure and mechanical properties of as-deposited films is investigated. It is found that the microstructure and the mechanical properties are both dependent on RN. The structures of NbMoTaW:O films and NbMoTaW:(N,O) films are body-centered cubic and face-centered cubic, respectively. With increasing RN, the hardness of the film reduces first and then increases, showing an anomalous effect of RN on the mechanical properties compared with previous results. The anomalous effect origins from the phase transformation, dislocation density and grain boundary hardening. The surface roughness and residual stress havelittle influence on the mechanical property.

Stress-induced phase transformation and phase boundary sliding in Ti: An atomically resolved in-situ analysis

In-situ tensile experiments on pure Ti were performed in a transmission electron microscope at room temperature. The dynamic process of stress-induced hexagonal closed-packed (hcp) to face-centered cubic (fcc) structural transformation ahead of a crack tip was captured at the atomic level. Intriguingly, a sliding behavior of the ensuing (0001)hcp/(11¯1)fcc phase boundary was observed to further accommodate the plastic deformation until crack initiation. The sliding was accomplished via the successive conservative glide of extended dislocations along the (0001)hcp/(11¯1)fcc phase boundary. A molecular dynamics simulation was carried out to corroborate the experiments and the results confirm the new dislocation-mediated sliding mechanism.

Reduced Space Optimization‐Based Evidence Theory Method for Response Analysis of Space‐Coiled Acoustic Metamaterials with Epistemic Uncertainty

Acoustic metamaterials have been widely concerned by researchers because of their excellent sound absorption properties. Traditional uncertainty analysis methods for response analysis of acoustic metamaterials with evidence variables have limitations. The excessive time spent on repetitive extreme analysis of focal elements severely impedes the practical application of evidence theory. To reduce the computational costs of uncertainty quantification for acoustic metamaterials under the evidence theory, a reduced space optimization‐based evidence theory method (RSO‐ETM) is proposed. In RSO‐ETM, a simplified surrogate model is first constructed by a modified adaptive arbitrary orthogonal polynomial (MAAOP) expansion method, and then, the monotonicity of the response surface is examined to reduce the space. Subsequently, the Newton iteration technique and a transformation boundary method are used to obtain the extreme points in the reduced space, through which the boundary of the response over each focal element can be readily obtained. By using RSO‐ETM, the optimization for each focal element can be avoided, and correspondingly the computational costs are reduced. Two mathematical examples and acoustic problems are employed to demonstrate the practicality of the methods.

Territorial Structure of Municipal Government at the Present Stage

The paper analyzes federal constitutional laws concerning the entry into the Russian Federation of its new constituent entities — Donetsk and Lugansk People’s Republics, Zaporozhye and Kherson regions — in terms of regulating territorial organization of local self-government. The author analyzes upcoming transformations, makes and justifies proposals regarding the need to expand the system of municipalities in new constituent entitties of the Russian Federation by including settlements as its local self-government territories. The implementation of such a provision will comply with Federal Law No. 131-FZ dated 06.10.2003 «On General Principles of Organization of Local Self-Government in the Russian Federation» and will allow the population of rural and other settlements to participate more actively in local self-government.The paper describes the principles of the territorial basis of local self-government and clarifies the possibilities of their preservation in the conditions of the ongoing transformations of local self-government, due to the introduction of amendments to the Constitution of the Russian Federation in 2020. The author characterizes the procedures fixed in the legislation for ensuring changes in the boundaries of municipalities, transformation and abolition of municipalities, analyzes the norms of relevant laws of constituent entitties of the Russian Federation and municipal legal acts specifying the procedure for solving territorial issues of local self-government, illustrates the process of consolidation of municipalities on the example of the Moscow region. It is noted that in the Russian Federation there is a three-level legal regulation of the municipal-territorial structure, including federal and regional legislation and municipal legal acts. This makes it possible to determine substantive powers of public authorities in this area of local self-government and establish the procedure for their enforcement. Taking into account the results obtained, draft Federal Law No. 40361-8 «On general principles of organization of local self-government in the unified system of public authority» is analyzed in order to identify the degree of stability of the existing system of territorial organization of local self-government. The author summarizes that adoption of the enactment under consideration will not entail significant changes, its principles and will not change the procedure for resolving issues of territorial organization of municipal power.