bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement of the martensitic stainless steel X46Cr13 by Q&P heat treatment
Authors: Dieck S , Ecke M , Halle T , Rosemann P 
Published: August 2020

Abstract
The innovative heat treatment concept of “Quenching and Partitioning” (Q&P) enables the production of high-strength martensitic steels with high ductility. Residual austenite is stabilized in the partitioning process by carbon diffusion. This enables the strain-induced phase transformation from austenite to martensite and increases the ductility without reducing the strength. So far, little research has been done on the application of the Q&P process on martensitic stainless steels and their related corrosion resistance. The present work supplements the first investigations by Yuang and Raabe with important material-technical parameters as well as the achievable corrosion resistance. The Q&P heat treatment offers enhanced mechanical properties and a higher corrosion resistance in comparison to the conventional quenching and tempering heat treatment.
On the effect of aluminum and chromium on the deformation twinning of body-centered cubic iron
Authors: Ecke M , Michael O , Halle T 
Published: August 2020

Abstract
This paper reports on investigations on the effect of aluminum and chromium on the formation of deformation twins in body-centered cubic iron. For this purpose, impact loading experiments (ε = 104 s−1) were carried out at room temperature on samples of iron and the alloys Fe-10at.-% Al and Fe-10at.-% Cr. Furthermore, the grain size was varied in order to consider the effect of the alloying elements for both fine-grained and coarse-grained microstructures. The investigations on twin formation were carried out by electron backscatter diffraction (EBSD) and by quantitative image processing using optical microscopy. The observations show a comparable twin portion in iron and Fe 10at.-% Cr after impact loading for both grain sizes. In the alloy Fe-10at.-% Al the portion of twins is significantly increased for fine-grain and coarse-grain state. In order to clarify the possible reason, X-ray diffraction analyses (XRD) were additionally carried out. These show a shift in the reflexes which can be attributed to an elastic distortion of the lattice. This lattice distortion due to the formation of solid solution correlates very well with the determined twin fractions.
Comparison of liquid and gel electrolytes for the investigation of pitting corrosion on stainless steels
Authors: Heyn A 
Published: August 2020

Abstract
Electrochemical methods have become established for the investigation and testing of stainless steels for their resistance to pitting corrosion. In contrast to liquid electrolytes, which are normally used for this purpose, gel-like electrolytes have clear advantages regarding their usability. However, it must be clarified whether both types of electrolyte lead to the same or different results. In the investigations presented here, various agar-based gel electrolytes were characterized regarding their corrosion-relevant properties, such as chemical composition, rheo-logical properties and the electrolyte film forming on the surface. To compare the two electrolyte types, electrochemical investigations were carried out with graduated agar and NaCl concentrations on the material 1.4301 (AISI 304). Pitting and repassivation potentials were determined by dynamic polarization experiments and the varied factors were statistically evaluated regarding their influence. The results show that liquid and gel electrolytes provide comparable results. However, the pitting corrosion phenomena under external polarization are shallower with gel electrolytes and therefore their repassivation is supported. Also, the use of gel electrolytes with indicators for iron ions, which at the same time act as oxidizing agents and allow polarization into critical areas, gives comparable results. Gel electrolytes are therefore a very good alternative to liquid electrolytes if the detection of corrosion-sensitive surfaces is in focus.
Recent advances in additive manufacturing of Mo-Si-B alloys – A status report on the cooperative project LextrA -
Authors: Krüger M , Schmelzer J , Fichtner D , Heinze C , Küsters Y , Rittinghaus S K , Weisheit A , Heinz R , Gerking L , Gruber K , Schmigalla S , Schultze S 
Published: August 2020

Abstract
Mo-Si-B alloys are potential materials for ultra-high temperature applications, e.g. as turbine blades. Due to their excellent mechanical properties they are subject to basic research for about 20 years. The next step towards industrial application of this type of alloys is to use the current knowledge on microstructure-properties relationships and combine this with innovative laser additive manufacturing (AM). This way of processing is very challenging since the melting point of Mo-Si-B materials is > 2000 °C and the brittle-to-ductile transition temperature is typically about 900 °C. The authors demonstrate that gas atomized Mo-Si-B powders of three different compositions could be successfully processed by different AM processes, namely Direct Energy Deposition (DED) and Laser Powder Bed Fusion (LPBF). It is verified that the mechanical and oxidation properties provided by the AM materials are comparable and competitive to similar alloy compositions from conventional processes.
Simulative and experimental investigations on single-sided resistance spot brazing of sheet metal tube connections as an alternative to single-sided resistance spot welding
Authors: Najuch M , Jüttner S , Schmicker D 
Published: August 2020

Abstract
In order to reduce the deficits in single-sided resistance welding (SSSW), single-sided resistance brazing is a promising alternative. The reason for this is a process-related reduced thermal and mechanical component impact compared to SSSW. In the underlying article, the single-sided resistance brazing process will therefore be presented. In addition to the process architecture, the process advantage is presented and the joining characteristics are clarified. Finally, the presumed process advantage is confirmed by means of a practical example.
Hydrogen diffusion and local Volta potential in high- and medium-entropy alloys
Authors: Rhode M , Wetzel A , Ozcan O , Nietzke J , Richter T , Schroepfer D 
Published: August 2020

AbstractHigh-entropy alloys (HEAs) are characterized by a solid solution of minimum five and medium-entropy alloys (MEAs) of minimum three principal alloying elements in equiatomic proportions. They show exceptional application properties, such as high-strength and ductility or corrosion resistance. Future HEA/MEA-components could be exposed to hydrogen containing environments like vessels for cryogenic or high-pressure storage where the hydrogen absorption and diffusion in these materials is of interest. In our study, we investigated the HEA Co20Cr20Fe20Mn20Ni20and the MEA Co33.3Cr33.3Ni33.3. For hydrogen ingress, cathodic charging was applied and diffusion kinetic was measured by high-resolution thermal desorption spectros-copy using different heating rates up to 0.250 K/s. Peak deconvolution resulted in high-temperature desorption peaks and hydrogen trapping above 280 °C. A total hydrogen concentration > 40 ppm was identified for the MEA and > 100 ppm for HEA. This indicates two important effects: (1) delayed hydrogen diffusion and (2) considerable amount of trapped hydrogen that must be anticipated for hydrogen assisted cracking phenomenon. Local electrochemical Volta potential maps had been measured for the hydrogen free condition by means of high-resolution Scanning Kelvin Probe Force Microscopy (SKPFM).
Influence of modern machining processes on the surface integrity of high-entropy alloys
Authors: Richter T , Schröpfer D , Rhode M , Börner A 
Published: August 2020

Abstract
High Entropy Alloys (HEAs) are a recent class of materials. In contrast to conventional alloys, HEAs consist of five alloying elements in equiatomic equilibrium. The high entropy effect is due, among other things, to the increased configuration entropy, which promotes solid solution formation. Many HEAs have enormous application potential due to excellent structural property combinations from very low to high temperatures. For the introduction of HEAs in real components, however, the question of the applicability of machining production technologies for component manufacture is of central importance. This has so far received little attention in global materials research. Reliable and safe processing is essential for the demand of economical component production for potential areas of application, e.g. in power plant technology. For metals, milling is the standard machining process. This article presents the results of machining analyses. It focuses on the surface integrity resulting from the milling process on a Co20Cr20Fe20Mn20Ni20-HEA. For this purpose, investigations were carried out using ball nose end milling tools for conventional milling process in comparison to an innovative hybrid process available at BAM Berlin, Ultrasonic-Assisted Milling (USAM). USAM promises a lower degradation of the surface properties due to lower loads on the workpiece surface during machining. For this purpose, basic milling parameters (cutting speed and tooth feed) were systematically varied and cutting forces were measured during the milling experiments. The subsequent analysis of these forces allows an understanding of the mechanical loads acting on the tool and component surface. These loads cause topographical, mechanical and microstructural influences on the surface and consequently on the surface integrity. For their characterization, light and scanning electron microscopy were used, and the roughness and residual stresses via X-ray diffraction were measured. The results indicate significant advantages using USAM, especially due to reduced cutting forces compared to the conventional milling process. This causes lower mechanical loads on the tool and surface, combined with lower tensile residual stresses on and below the surface, and ultimately results in a significantly enhanced surface integrity.
KorroPad testing - applications from industry and research
Authors: Rosemann P , Kauss N , Heyn A 
Published: August 2020

Abstract
The pitting corrosion resistance of stainless steels can be assessed with the KorroPad test in a very simple, quick and inexpensive way. The KorroPad is therefore an interesting alternative to time-consuming long-term tests and complex electrochemical investigations for manufacturers, processors and users of stainless steels. In this article, the basic functionality of the KorroPad is described and selected examples from industry and research illustrate it´s application. The assessment of grinding processes and post-weld treatment are first presented as relevant examples regarding industrial surface treatments on the pitting corrosion resistance. Subsequently, current research to the modification of the KorroPad test is presented, which shows the specific detection limit of KorroPads on binary Fe-Cr reference alloys. Finally, modified KorroPads are used to detect microstructure related susceptibility to pitting corrosion induced by sensitizing heat treatment. The KorroPad enables the creation of a sensitization T-t diagram based on the pitting corrosion resistance.
Sensitization behaviour of the nitrogen alloyed austenitic stainless steel X8CrMnMoN18-19-2
Authors: Rosemann P , Müller C , Halle T 
Published: August 2020

Abstract
Austenitic stainless steels have been used in many different industrial branches. Nitrogen alloyed austenite´s with up to 20 wt. % manganese and 0.8 wt. % nitrogen have been available on the market as nickel-free grade for some years. In these steels, the austenitic matrix is stabilized without the addition of nickel, while the corrosive resistance and mechanical properties are significantly improved by addition of Mn and N. As with all stainless steels, the chemical composition and heat treatment have a decisive influence on structure, mechanical properties and corrosion resistance. Solution annealing, quenching and work hardening are applied to combine excellent mechanical properties (Rm from 900 MPa to 2,000 MPa, A5 > 50 %, Av > 350 J) with high corrosion resistance. Solution annealing is applied to eliminate undesired precipitation phases (Cr2N, M23C6 and sigma phase), distribute the alloy elements homogeneously in the austenite and assure the high corrosion resistance. If the distribution of the alloy elements (Cr, Mo and N) is impaired by suboptimal heat treatment, processing or high temperature conditions, the corrosion resistance can be reduced. Precise knowledge of the sensitization behaviour of these high nitrogen alloyed steels is necessary. Therefore, the sensitization behaviour of the nitrogen alloyed austenitic steel X8CrMnMoN18-19-2 (1.4456) was investigated by thermal ageing in the temperature rage of 500 °C to 900 °C for up to 100 h. Thermodynamic calculations were used to predict the formation of different phases. The microstructure of the various sensitization states was evaluated by scanning electron microscopy (SEM) and compared with the corrosion resistance characterized by the electrochemical potentiodynamic reactivation (EPR) test and the KorroPad method. The reduction of corrosion resistance is correlated with the occurrence of M2N nitrides in the microstructure and two sensitization diagrams were created based on the experimental results.
Einfluss des Umwandlungs- und Erstarrungsverhaltens nicht-rostender Chrom-Nickel-Stähle auf die Schweißeignung beim Hochleistungsschweißen
Authors: Schuster J 
Published: August 2020

AbstractInhalt. Die Zielstellung der vorgestellten Untersuchungen bestand in der Klärung des Einflusses der gegenüber den herkömmlichen Schweißprozessen größeren Abkühlgeschwindigkeit des Laserstahlschweißens auf das Erstarrungs- und Umwandlungsverhalten hochlegierter Chrom-Nickel-(Molybdän)Stähle. Wie nachgewiesen werden konnte, treffen für Strahlschweißprozesse u. U. die Iso-Ferritlinien im WRC-92- und im SCHAEFFLER-Diagramm nicht mehr zu. Dabei zeigt das SCHAEFFLER-Diagramm Erstarrungswechsel besser an als das WRC-92-Diagramm. So verschiebt sich im WRC-92-Diagramm der Erstarrungswechsel zu höheren Werten des Ni-Äquivalents.
First principles density functional theory calculations on the elastic properties of Mo-Si based solid solutions
Authors: Touzani R S , Krüger M 
Published: August 2020

Abstract
The alloy system Mo-Si-B gained a lot of attention, as it showed superior elastic properties than currently used Ni based superalloys at elevated temperatures. In the Mo-Si-B alloy system, Mo based solid solutions play an important role as a compound and one can observe a solid solution with small amounts of Si and tiny, almost negligible, amounts of B. To improve the ductility of this alloy at higher temperatures, titanium is added and as a result Mo-Si-Ti solid solutions are formed. To get an idea of the elastic properties of new Mo based solid solutions, first principles density functional theory calculations serve as a powerful method for the prediction and qualitative, often almost quantitative results for the elastic moduli are achieved. Here we show the elastic properties like bulk, shear and Young’s modulus as well as the Vickers hardness, calculated with first principles density functional theory (DFT), of Mo-Si-B-Ti based solid solutions with approximated atom concentrations Mo-1 at.% Si, Mo-3 at.% Si, Mo-2 at.% Si-1 at.% Ti, Mo-3 at.% Si-1 at.% B and Mo-3 at.% Si-1 at.% Ti.
Microstructural Characterization of Quenched and Partitioned commercial Medium Carbon Steel
Authors: Wilke A , Dieck S , Härtel M , Lampke T , Halle T 
Published: August 2020

Abstract
In order to achieve the desired properties, the microstructure of metals is often modified by heat treatments. A suitable combination of high strength and good ductility can be achieved by adjusting the amounts of martensite and retained austenite through a Quenching and Partitioning (Q&P) process. Controlling these material properties offers new potentials in the production of light weight steel parts. This paper presents a basic study of heat treatment conditions with subsequent microstructural characterization of quenched and partitioned commercial 0.54C-1.45Si-0.71Mn spring steel. Beginning from full austenitization, different quenching and partitioning parameters were applied. Microstructural characterization was performed using optical microscopy in combination with different etching methods as well as Scanning Electron Microscopy (SEM) and Electron Backscattered Diffraction (EBSD). It is shown that the intended dual phase microstructure with a specific phase fraction of austenite can be produced. Those results and consideration of hardness measurements show that the investigated commercial spring steel is a promising candidate for improving mechanical properties by a Q&P process.
Pyroelectric X-ray Generator for XRF in Combination with Optical Microscopy
Authors: Wilke M , Hanns L , Harnisch K , Knapp W , Ecke M , Halle T 
Published: August 2020

Abstract
X-ray fluorescence spectroscopy (XRF) is a method for elemental analyses of materials. In comparison to other analysing methods such as energy dispersive X-Ray spectroscopy (EDS) within a scanning electron microscope (SEM) or optical emission spectroscopy (OES) there are several advantages. This paper contains experimental investigations to improve the emission behaviour of a pyroelectric X-ray source regarding X-ray energy and output intensity. Pyroelectric lithiumtantalate (LiTaO3) was used to emit and accelerate electrons and to generate primary X-rays subsequently. Geometrical conditions were altered and the design of the X-ray source was optimized. All steps of optimization have been performed with respect to an application in a spectroscopic device in combination with an optical microscope (OM). Based on this purpose, the miniaturization of all applied components is of major importance. Different pure metals, alloys, and a coated specimen were analysed to demonstrate potential applications and current limitations of the designed system. Materials with a wide range of necessary excitation energy for chemical analyses of 1.5 to 10 keV for the Kα and Lα X-ray fluorescent lines were used to demonstrate the technical relevance of this type of application. As a result, a prototype of a spectrometer that combines XRF and OM was designed and tested.
What Can Mechanisms Underlying Derived Traits Tell Us About the Evolution of Social Behavior?
Authors: Treanore Erin , Derstine Nathan , Amsalem Etya 
Published: August 2020

AbstractSocial behavior, although rare, is a highly successful form of living that has reached its most extreme forms in eusocial insects. A tractable framework to understand social evolution is the study of major transitions in social behavior. This includes the transitions between solitary to social living, from species exhibiting intermediate degrees of sociality to species exhibiting true sociality, and from primitive to advanced eusocial species. The latter transition is characterized by the emergence of traits not previously found in primitive eusocial species, such as fixed morphological differences between castes and task specialization within the sterile caste. Such derived traits appear to exist in a binary fashion, present in advanced eusocial species, and absent or rare in primitive ones, and thus do not exist in a gradient that is easily tracked and compared between species. Thus, they may not be viewed as valuable to explore ultimate questions related to social evolution. Here, we argue that derived traits can provide useful insights on social evolution even if they are absent or rare in species with a lower social organization. This applies only if the mechanism underlying the trait, rather than the function it regulates for, can be traced back to the solitary ancestors. We discuss two examples of derived traits, morphological differences in female castes and primer pheromones regulating female reproduction, demonstrating how their underlying mechanisms can be used to understand major transitions in the evolution of social behavior and emphasize the importance of studying mechanistic, rather than functional continuity of traits.
A Likelihood Ratio Test for Gene-Environment Interaction Based on the Trend Effect of Genotype Under an Additive Risk Model Using the Gene-Environment Independence Assumption
Authors: de Rochemonteix Matthieu , Napolioni Valerio , Sanyal Nilotpal , Belloy Michaël E , Caporaso Neil E , Landi Maria T , Greicius Michael D , Chatterjee Nilanjan , Han Summer S 
Published: August 2020

Abstract
Several statistical methods have been proposed for testing gene-environment (G-E) interactions under additive risk models using data from genome-wide association studies. However, these approaches have strong assumptions from underlying genetic models, such as dominant or recessive effects that are known to be less robust when the true genetic model is unknown. We aimed to develop a robust trend test employing a likelihood ratio test for detecting G-E interaction under an additive risk model, while incorporating the G-E independence assumption to increase power. We used a constrained likelihood to impose 2 sets of constraints for: 1) the linear trend effect of genotype and 2) the additive joint effects of gene and environment. To incorporate the G-E independence assumption, a retrospective likelihood was used versus a standard prospective likelihood. Numerical investigation suggests that the proposed tests are more powerful than tests assuming dominant, recessive, or general models under various parameter settings and under both likelihoods. Incorporation of the independence assumption enhances efficiency by 2.5-fold. We applied the proposed methods to examine the gene-smoking interaction for lung cancer and gene–apolipoprotein E $\varepsilon$4 interaction for Alzheimer disease, which identified 2 interactions between apolipoprotein E $\varepsilon$4 and loci membrane-spanning 4-domains subfamily A (MS4A) and bridging integrator 1 (BIN1) genes at genome-wide significance that were replicated using independent data.
Are Physical Activity, Screen Time, and Mental Health Related During Childhood, Preadolescence, and Adolescence? 11-Year Results From the German Motorik-Modul Longitudinal Study
Authors: Nigg Claudio R , Wunsch Kathrin , Nigg Carina , Niessner Claudia , Jekauc Darko , Schmidt Steffen C E , Woll Alexander 
Published: August 2020

AbstractMental health (MH) and behavioral health are fundamental to a good quality of life. Only a few studies have investigated the association between behavioral health (e.g., physical activity (PA), screen time (ST)) and MH from childhood to adolescence. Therefore, we investigated the relationships of PA and ST with MH by sex in an 11-year longitudinal cohort study of German schoolchildren during 2003–2017. A subsample (n = 686; 55.2% female) of participants from the German Motorik-Modul (MoMo) Longitudinal Study who participated in all 3 measurement phases (mean ages: time 1 (baseline; 2003–2006), 5.57 (standard deviation (SD), 1.00) years; time 2 (wave 1; 2009–2012), 11.85 (SD, 1.03) years; time 3 (wave 2; 2014–2017), 16.86 (SD, 1.04) years) were analyzed with regard to PA, ST, and MH (emotional symptoms, conduct problems, hyperactivity/inattention, peer relationship problems, prosocial behavior, and overall strengths and difficulties). Path panel prediction models were fitted with time 1, time 2, and time 3 PA, ST, and MH indicators. PA predicted less television (TV)/video watching in females, and TV/video watching predicted personal computer (PC)/Internet use in both sexes. Behavior and MH results suggested that, for females, higher TV/video watching and PC/Internet use was related to higher MH challenges over the course of maturation. Some preadolescent males’ MH challenges increased ST (TV/video watching and PC/Internet use) in adolescence. Researchers should explore innovative and effective methods for reducing childhood ST, especially among females with early signs of MH issues, and addressing preadolescent males’ MH challenges.