Fungal biorefinery is a popular method for producing advanced fabrics but is currently limited to leather alternatives and similar by the sheet-based nature of most fungal materials. Biopolymers in the fungal cell wall, such as chitin and chitosan, are only soluble in harsh chemicals, making established extrusion-based yarn production systems expensive and hazardous. The Japanese art of Shifu is used to produce fungal chitin-β-glucan yarns of varying linear density from engineered fungal sheets, enabling the production of yarns. Yarn mechanical strength is influenced by sheet precursor grammage and can be tuned using various chemical modifications such as glycerol-based plasticization. Yarns hybridized with nanocellulose exhibited low strength, stiffness, and ductility, due to weak interfacing with fungal sheets. With mechanical properties outperforming commercial cellulose paper yarns and on par with cotton and viscose yarns, fungal yarns produced from engineered sheets of fungal biomass using Shifu techniques represent a viable yarn candidate for a broad range of applications, yet unachieved using fungi, such as textiles, upholstery, and carpets for the fashion and décor sectors. ... Read more

The quenching and partitioning (Q&P) process is a heat treatment process, aiming at the creation of steel microstructures composed of martensite and retained austenite. Herein, the thermal stability of the microstructure is investigated upon reheating steel microstructures, created with different Q&P settings, in different thermal routes, using dilatometry and thermomagnetometry to quantitatively monitor phase fractions. Analysis of the derivative of dilatometry curves and thermomagnetic data reveals that upon reheating the retained austenite decomposes. The decomposition occurs in two stages when the heating rate is relatively low. The retained austenite completely transforms to ferrite and cementite upon reheating to 550 °C, followed by isothermal holding for 1800 s. Increasing the partitioning time from 50 to 300 s at 400 °C after quenching to 260 °C significantly increases the thermal stability of retained austenite. In all conditions, both carbon-depleted martensite (formed in the initial quenching step) and fresh martensite (formed in final Q&P quenching) are found to be partially tempered during the reheating experiments. ... Read more

This paper presents a detailed characterization of the microstructural development of a new quenching and partitioning (Q&P) steel. Q&P treatments, starting from full austenitization, were applied to the developed steel, leading to microstructures containing volume fractions of retained austenite of up to 0.15. The austenite was distributed as films in between the martensite laths. Analysis demonstrates that, in this material, stabilization of austenite can be achieved at significantly shorter time scales via the Q&P route than is possible via a bainitic isothermal holding. The results showed that the thermal stabilization of austenite during the partitioning step is not necessarily accompanied by a significant expansion of the material. This implies that the process of carbon partitioning from martensite to austenite occurs across low-mobility martensite–austenite interfaces. The amount of martensite formed during the first quench has been quantified. Unlike martensite formed in the final quench, this martensite was found to be tempered during partitioning. Measured volume fractions of retained austenite after different treatments were compared with simulations using model descriptions for carbon partitioning from martensite to austenite. Simulation results confirmed that the carbon partitioning takes place at low-mobility martensite–austenite interfaces. ... Read more

This study focuses on the dissolution and growth of small possibly initially non-smooth particles within a diffusive phase. The dissolution or growth of the particle is assumed to be affected by concentration gradients of a single chemical element within the diffusive phase at the particle boundary caused by diffusion and by an interface reaction. The combined formulation results in a mixed-mode formulation. The moving boundary problem is solved using a level-set method and finite-element techniques such as SUPG. The appropriate meshes are derived using a fixed background mesh and the level-set function. We experimentally show that these techniques give mass-conserving solutions in the limit of infinite resolution, give a linear experimental order of convergence, can handle arbitrary particles and give the possibility to incorporate surface tensions using the Gibbs-Thomson effect and the local curvature. ... Read more

The quenching and partitioning (Q&P) process is a new heat treatment for the creation of advanced high-strength steels. This treatment consists of an initial partial or full austenitization, followed by a quench to form a controlled amount of martensite and an annealing step to partition carbon atoms from the martensite to the austenite. In this work, the microstructural evolution during annealing of martensite–austenite grain assemblies has been analyzed by means of a modeling approach that considers the influence of martensite–austenite interface migration on the kinetics of carbon partitioning. Carbide precipitation is precluded in the model, and three different assumptions about interface mobility are considered, ranging from a completely immobile interface to the relatively high mobility of an incoherent ferrite–austenite interface. Simulations indicate that different interface mobilities lead to profound differences in the evolution of microstructure that is predicted during annealing. ... Read more