Influence of particles on recrystallization textures of ferritic stainless steels

Five microalloyed ferritic steels with a Cr content of 10 to 17 % were cold rolled and recrystallized. Steels with a high volume fraction of Nb and Ti precipitations revealed a deviation from the typical {111} fibre texture. The new main component {557}<583> was explained by particle induced growth selection.     

Manipulation of matter by electric and magnetic fields: Toward novel synthesis and processing routes of inorganic materials

The use of external electric and magnetic fields for the synthesis and processing of inorganic materials such as metals and ceramics has seen renewed interest in recent years. Electromagnetic energy can be utilized in different ways to improve or accelerate phase formation and stabilization, chemical ordering, densification and coarsening of particle-based materials (pore elimination and grain growth), and mechanical deformation (plasticity and creep). In these new synthesis and processing routes, the resulting microstructures and macroscopic material behavior are determined by the interaction of the applied fields with defects such as single or clustered point defects, dislocation networks, and interfaces. Multiscale experimental investigations and modeling are necessary to unveil the mechanisms underlying this field-assisted manipulation of matter.     

A Comprehensive Review of Genetically Engineered Mouse Models for Prader-Willi Syndrome Research

Prader-Willi syndrome (PWS) is a neurogenetic multifactorial disorder caused by the deletion or inactivation of paternally imprinted genes on human chromosome 15q11-q13. The affected homologous locus is on mouse chromosome 7C. The positional conservation and organization of genes including the imprinting pattern between mice and men implies similar physiological functions of this locus. Therefore, considerable efforts to recreate the pathogenesis of PWS have been accomplished in mouse models. We provide a summary of different mouse models that were generated for the analysis of PWS and discuss their impact on our current understanding of corresponding genes, their putative functions and the pathogenesis of PWS. Murine models of PWS unveiled the contribution of each affected gene to this multi-facetted disease, and also enabled the establishment of the minimal critical genomic region (PWScr) responsible for core symptoms, highlighting the importance of non-protein coding genes in the PWS locus. Although the underlying disease-causing mechanisms of PWS remain widely unresolved and existing mouse models do not fully capture the entire spectrum of the human PWS disorder, continuous improvements of genetically engineered mouse models have proven to be very powerful and valuable tools in PWS research.     

Alloy Design,Combinatorial Synthesis,and Microstructure–Property Relations for Low-Density Fe-Mn-Al-C Austenitic Steels

We present recent developments in the field of austenitic steels with up to 18% reduced mass density. The alloys are based on the Fe-Mn-Al-C system. Here, two steel types are addressed. The first one is a class of low-density twinning-induced plasticity or single phase austenitic TWIP (SIMPLEX) steels with 25–30 wt.% Mn and <4–5 wt.% Al or even <8 wt.% Al when naturally aged. The second one is a class of κ-carbide strengthened austenitic steels with even higher Al content. Here, κ-carbides form either at 500–600°C or even during quenching for >10 wt.% Al. Three topics are addressed in more detail, namely, the combinatorial bulk high-throughput design of a wide range of corresponding alloy variants, the development of microstructure–property relations for such steels, and their susceptibility to hydrogen embrittlement.     

Simulation of dislocation penetration through a general low-angle grain boundary

The interaction of dislocations with low-angle grain boundaries (LAGBs) is considered one important contribution to the mechanical strength of metals. Although LAGBs have been frequently observed in metals, little is known about how they interact with free dislocations that mainly carry the plastic deformation. Using discrete dislocation dynamics simulations, we are able to quantify the resistance of a LAGB—idealized as three sets of dislocations that form a hexagonal dislocation network—against lattice dislocation penetration, and examine the associated dislocation processes. Our results reveal that such a coherent internal boundary can massively obstruct and even terminate dislocation transmission and thus make a substantial contribution to material strength.     

A 2D approximation of standard electrical steel losses and permeability

A first design approach for an electrical machine need not be done with the efforts of detailed magnetic field considerations. Often a more pragmatic way already fulfills the desired accuracy. Performing fast by hand calculations depends on the data that is available; for e.g., the lamination geometry or material. This article provides a table for different electrical steels that can be used in the analytical calculation of magnetic circuits. In comparison with existing publications this article shows two-dimensional functions for the specific iron losses and the relative permeability. Both magnetic flux density and frequency are input variables.     

Solvent Influence on the Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H‐MFI 90 Catalysts

Second generation biofuels are produced in the bioliq® process at the Karlsruhe Institute of Technology via gasification of pyrolysis oil and synthesis of gasoline from the emerging synthesis gas. An alternative strategy is the direct upgrading of the pyrolysis oil by hydrodeoxygenation (HDO). The present study reports on the HDO of guaiacol as one of the phenolic compounds strongly abundant in such mixtures. Special focus was laid on the solvent influence using Pt‐based catalysts. Higher HDO ability was seen using nonpolar solvents and acidic supports. Characterization of the catalysts before and after the test showed that the solvent did not only influence the reactivity, but also the catalyst stability.     

Optimizing continuous annealing of interstitial-free steels for improving deep drawability

The crystallographic textures and the resulting plastic anisotropy of five interstitial-free (IF) steels with different carbon equivalents and Nb and Ti microalloying content have been investigated. The steels were industrially hot rolled, cold rolled, annealed, and finally hot-dip galvanized. An alternative heat treatment of the cold rolled samples was conducted in laboratory scale using parameters close to those in industry-scale continuous annealing lines. The anisotropy parameters were both measured and predicted on the basis of the measured texture data. The calculated values were corrected by using functions that were fitted to the experimental data. It was found that for a given hot and cold rolling state even minor changes in the annealing conditions can improve the anisotropy parameter by up to 13 pct. Increase in recrystallization texture and improvement of the resulting anisotropy parameters are discussed in terms of partial transformation of ferrite to austenite in the intercritical regime.