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A physically-informed continuum crystal plasticity model is presented to elucidate deformation mechanisms, dislocation evolution and the non-Schmid effect in body-centered-cubic (bcc) tantalum widely used as a key structural material for mechanical and thermal extremes. We show the unified structural modeling framework informed by mesoscopic dislocation dynamics simulations is capable of capturing salient features of the large inelastic behavior of tantalum at quasi-static (10−3 s−1) to extreme strain rates (5000 s−1) and at low (77 K) to high temperatures (873 K) at both single- and polycrystal levels. We also present predictive capabilities of the model for microstructural evolution in the material. To this end, we investigate the effects of dislocation interactions on slip activities, instability and the non-Schmid behavior at the single crystal level. Furthermore, ex situ measurements on crystallographic texture evolution and dislocation density growth are carried out for polycrystal tantalum specimens at increasing strains. Numerical simulation results also support that the modeling framework is capable of capturing the main features of the polycrystal behavior over a wide range of strains, strain rates and temperatures. The theoretical, experimental and numerical results at both single- and polycrystal levels provide critical insight into the underlying physical pictures for micro- and macroscopic responses and their relations in this important class of refractory bcc materials undergoing large inelastic deformations. 

Abstract The development of electronic devices from naturally derived materials is of enormous scientific interest. Melanin, a dark protective pigment ubiquitous in living creatures, may be particularly valuable because of its ability to conduct charges both electronically and ionically. However, device applications are severely hindered by its relatively poor electrical properties. Here, the facile preparation of conductive melanin composites is reported in which melanin nanoparticles (MNPs), directly extracted from squid inks, form electrically continuous junctions by tight clustering in a poly(vinyl alcohol) (PVA) matrix. Prepared as freestanding films and patterned microstructures by a series of precipitation, dry casting, and post‐thermal annealing steps, the percolated composites show electrical conductivities as high as 1.17 ± 0.13 S cm⁻¹at room temperature, which is the best performance yet obtained with biologically‐derived nanoparticles. Furthermore, the biodegradability of the MNP/PVA composites is confirmed through appetitive ingestion byZophobas morioslarvae (superworms). This discovery for preparing versatile biocomposites suggests new opportunities in functional material selections for the emerging applications of implantable, edible, green bioelectronics.