Tobias Brink

Tobias Brink
Max Planck Institute for Iron Research GmbH | MPIE · Department of Structure and Nano-/ Micromechanics of Materials

Dr.-Ing.

About

29
Publications
7,153
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504
Citations
Citations since 2016
26 Research Items
495 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120

Publications

Publications (29)
Article
In the last few decades, it has been recognized that a single grain boundary (GB) may exist in several different stable and metastable states, which differ in their atomic structure. However, experimental insights at the atomic structure level are rarely reported. In this study, two different microstates of incoherent Σ3 [111] (112¯) GBs from two d...
Preprint
Full-text available
Building on an analogy to ductile fracture mechanics, we quantify the size of debris particles created during adhesive wear. Earlier work suggested a linear relation between tangential work and wear debris volume, assuming that the debris size is proportional to the micro contact size multiplied by the junction shear strength. However, the present...
Article
Full-text available
The phase behavior of grain boundaries can have a strong influence on interfacial properties. Little is known about the emergence of grain boundary phases in elemental metal systems and how they transform. Here, we observe the nanoscale patterning of a grain boundary by two alternating grain boundary phases with distinct atomic structures in elemen...
Article
Frictional contacts lead to the formation of a surface layer called the third body, consisting of wear particles and structures resulting from their agglomerates. Its behavior and properties at the nanoscale control the macroscopic tribological performance. It is known that wear particles and surface topography evolve with time and mutually influen...
Article
Full-text available
Grain boundaries (GBs) in metals usually increase electrical resistivity due to their distinct atomic arrangement compared to the grain interior. While the GB structure has a crucial influence on the electrical properties, its relationship with resistivity is poorly understood. Here, we perform a systematic study on the resistivity–structure relati...
Preprint
Full-text available
The phase behavior of grain boundaries can have a strong influence on interfacial properties. Little is known about the emergence of grain boundary phases in elemental metal systems and how they transform. Here, we observe the nanoscale patterning of a grain boundary by two alternating grain boundary phases with distinct atomic structures in elemen...
Article
Full-text available
We report experimental measurements of friction between an aluminum alloy sliding over steel with various lubricant densities. Using the topography scans of the surfaces as input, we calculate the real contact area using the boundary element method and the dynamic friction coefficient by means of a simple mechanistic model. Partial lubrication of t...
Preprint
Full-text available
Grain boundaries (GBs) in metals usually increase electrical resistivity due to their distinct atomic arrangement compared to the grain interior. While the GB structure has a crucial influence on the electrical properties, its relationship with resistivity is poorly understood. Here, we perform a systematic study on the resistivity and structure re...
Preprint
Full-text available
Frictional contacts lead to the formation of a surface layer called the third body, consisting of wear particles and structures resulting from their agglomerates. Its behaviour and properties at the nanoscale control the macroscopic tribological performance. It is known that wear particles and surface topography evolve with time and mutually influe...
Article
Full-text available
In order to develop predictive wear laws, relevant material parameters and their influence on the wear rate need to be identified. Despite decades of research, there is no agreement on the mathematical form of wear equations and even the simplest models, such as Archard’s, contain unpredictable fit parameters. Here, we propose a simple model for ad...
Article
Adhesion between two bodies is a key parameter in wear processes. At the macroscale, strong adhesive bonds are known to lead to high wear rates, as observed in clean metal-on-metal contact. Reducing the strength of the interfacial adhesion is then desirable, and techniques such as lubrication and surface passivation are employed to this end. Still,...
Preprint
Full-text available
In order to develop predictive wear laws, relevant material parameters and their influence on the wear rate need to be identified. Despite decades of research, there is no agreement on the mathematical form of wear equations and even the simplest models, such as Archard's, contain unpredictable fit parameters. Here, we propose a simple model for ad...
Preprint
Adhesion between two bodies is a key parameter in wear processes. At the macroscale, strong adhesive bonds are known to lead to high wear rates, as observed in clean metal-on-metal contact. Reducing the strength of the interfacial adhesion is then desirable, and techniques such as lubrication and surface passivation are employed to this end. Still,...
Article
Current engineering wear models are often based on empirical parameters rather than built upon physical considerations. Here, we look for a physical description of adhesive wear at the microscale, at which the interaction between two surfaces comes down to the contact of asperities. Recent theoretical work has shown that there is a critical micro-c...
Article
We study the creep behavior of Cu64Zr36 glass-crystal nanocomposites under elastostatic loading conditions in molecular dynamics simulations. By manipulating the glass-crystal interfaces of a precipitation-annealed glass containing Laves-type crystallites, we show that the creep behavior can be tuned. Specifically, we find that for the same microst...
Preprint
Full-text available
Current engineering wear models are often based on empirical parameters rather than built upon physical considerations. Here, we look for a physical description of adhesive wear at the microscale, at which the interaction between two surfaces comes down to the contact of asperities. Recent theoretical work has shown that there is a critical micro-c...
Article
Engineering wear models are generally empirical and lack connections to the physical processes of debris generation at the nanoscale to microscale. Here, we thus analyze wear particle formation for sliding interfaces in dry contact with full and reduced adhesion. Depending on the material and interface properties and the local slopes of the surface...
Article
Full-text available
Friction and wear depend critically on surface roughness and its evolution with time. An accurate control of roughness is essential to the performance and durability of virtually all engineering applications. At geological scales, roughness along tectonic faults is intimately linked to stick-slip behaviour as experienced during earthquakes. While n...
Preprint
Engineering wear models are generally empirical and lack connections to the physical processes at the nano- to micro-scale. Here, we thus analyze wear particle formation for sliding interfaces in dry contact with full and reduced adhesion. Depending on the material and interface properties and the local slopes of the surfaces, we find that collidin...
Article
Full-text available
In this review, we discuss our recent advances in modeling adhesive wear mechanisms using coarse-grained atomistic simulations. In particular, we present how a model pair potential reveals the transition from ductile shearing of an asperity to the formation of a debris particle. This transition occurs at a critical junction size, which determines t...
Article
Full-text available
Nanocrystalline metals contain a large fraction of high-energy grain boundaries, which may be considered as glassy phases. Consequently, with decreasing grain size, a crossover in the deformation behaviour of nanocrystals to that of metallic glasses has been proposed. Here, we study this crossover using molecular dynamics simulations on bulk glasse...
Preprint
Full-text available
Nanocrystalline metals contain a large fraction of high-energy grain boundaries, which may be considered as glassy phases. Consequently, with decreasing grain size, a crossover in the deformation behaviour of nanocrystals to that of metallic glasses has been proposed. Here, we study this crossover using molecular dynamics simulations on bulk glasse...
Article
Full-text available
Wear is the inevitable damage process of surfaces during sliding contact. According to the well-known Archard’s wear law, the wear volume scales with the real contact area and as a result is proportional to the load. Decades of wear experiments, however, show that this relation only holds up to a certain load limit, above which the linearity is bro...
Article
In this work we present molecular dynamics simulations on the creep behavior of $\rm Cu_{64}Zr_{36}$ metallic glass composites. Surprisingly, all composites exhibit much higher creep rates than the homogeneous glass. The glass-crystal interface can be viewed as a weak interphase, where the activation of shear transformation zones is lower than in t...
Article
Full-text available
We study order transitions and defect formation in a model high-entropy alloy (CuNiCoFe) under ion irradiation by means of molecular dynamics simulations. Using a hybrid Monte-Carlo/molecular dynamics scheme a model alloy is generated which is thermodynamically stabilized by configurational entropy at elevated temperatures, but partly decomposes at...
Article
The boson peak appears in all amorphous solids and is an excess of vibrational states at low frequencies compared to the phonon spectrum of the corresponding crystal. Until recently, the consensus was that it originated from "defects" in the glass. The nature of these defects is still under discussion, but the picture of regions with locally distur...
Article
Full-text available
Solid-state amorphization of crystalline copper nanolayers embedded in a Cu64Zr36 metallic glass is studied by molecular dynamics simulations for different orientations of the crystalline layer. We show that solid-state amorphization is driven by a reduction of interface energy, which compensates the bulk excess energy of the amorphous nanolayer wi...
Article
Full-text available
The interaction of shear bands with crystalline nanoprecipitates in Cu-Zr-based metallic glasses is investigated by a combination of high-resolution TEM imaging and molecular dynamics computer simulations. Our results reveal different interaction mechanisms: Shear bands can dissolve precipitates, can wrap around crystalline obstacles or can be bloc...
Article
Full-text available
The low temperature heat capacity of amorphous materials reveals a low-frequency enhancement (boson peak) of the vibrational density of states, as compared with the Debye law. By measuring the low-temperature heat capacity of a Zr-based bulk metallic glass relative to a crystalline reference state, we show that the heat capacity of the glass is str...

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