Anomalous{1012}tensile twinning and subsequent detwinning in a friction stir processed carbon fiber-reinforced Mg composite

1.Main text Owing to their low density and high specific strength,magnesium alloys and magnesium-based composites have great potential as structure metal materials in applications where lightweight matters[1–4].Deformation twins[5],especially the{1012}tension twins(also called tensile or extension twins)with a low critical resolved shear stress(CRSS)[6],are commonly observed in Mg alloys.They can provide the much-needed deformation along the c-axis in their hcp structure resulting from the very few easily activated slip systems in this crystal structure[7].The tensile twinning activation usually follows the macroscopic Schmid factor law[2],i.e.,the twin variant with the highest Schmid factor occurs,and it only appears when its Schmid factor is positive.

Enhanced tensile ductility of tungsten microwires via high-density dislocations and reduced grain boundaries

Despite being strong with many outstanding physical properties,tungsten is inherently brittle at room temperature,restricting its structural and functional applications at small scales.Here,a facile strategy has been adopted,to introduce high-density dislocations while reducing grain boundaries,through electron backscatter diffraction(EBSD)-guided microfabrication of cold-drawn bulk tungsten wires.The designed tungsten microwire attains an ultralarge uniform tensile elongation of~10.6%,while retains a high yield strength of~2.4 GPa.in situ TEM tensile testing reveals that the large uniform elongation of tungsten microwires originates from the motion of pre-existing high-density dislocations,while the subsequent ductile fracture is attributed to crack-tip plasticity and the inhibition of grain boundary cracking.This work demonstrates the application potential of tungsten microcomponents with superior ductility and workability for micro/nanoscale mechanical,electronic,and energy systems.

In situ mechanical characterization of silver nanowire/graphene hybrids films for flexible electronics

Flexible transparent conductive films are indispensable for nowadays wearable electronic devices with various applications.However,existing solutions such as ITO and metal mesh were limited by their poor intrinsic stretching ability.In this work,we designed and fabricated silver nanowires(AgNWs)on graphene hybrid films for enhanced mechanical and electrical performance.In situ TEM characterizations show that,beside conductive paths,silver nanowire network,can also contribute to the toughening mechanisms of the hybrid films.Furthermore,bending and electrical tests were applied to examine the corresponding flexible electronics’perfor-mance.Finally,we showed that the fabrication of our AgNW/graphene hybrid films could be scaled up for large film applications and extended to other 1D/2D hybrid systems.