Finding and Characterising Active Slip Systems: A Short Review and Tutorial with Automation Tools.

The behaviour of many materials is strongly influenced by the mechanical properties of hard phases, present either from deliberate introduction for reinforcement or as deleterious precipitates. While it is, therefore, self-evident that these phases should be studied, the ability to do so-particularly their plasticity-is hindered by their small sizes and lack of bulk ductility at room temperature. Many researchers have, therefore, turned to small-scale testing in order to suppress brittle fracture and study the deformation mechanisms of complex crystal structures. To characterise the plasticity of a hard and potentially anisotropic crystal, several steps and different nanomechanical testing techniques are involved, in particular nanoindentation and microcompression. The mechanical data can only be interpreted based on imaging and orientation measurements by electron microscopy. Here, we provide a tutorial to guide the collection, analysis, and interpretation of data on plasticity in hard crystals. We provide code collated in our group to help new researchers to analyse their data efficiently from the start. As part of the tutorial, we show how the slip systems and deformation mechanisms in intermetallics such as the Fe7Mo6 µ-phase are discovered, where the large and complex crystal structure precludes determining a priori even the slip planes in these phases. By comparison with other works in the literature, we also aim to identify "best practises" for researchers throughout to aid in the application of the methods to other materials systems.

Effects of Gd element and SiC particles on microstructures of Cf/Mg composites.

In present work, Cf/Mg-8Gd and SiC+Cf/Mg-8Gd composites were fabricated by squeeze infiltration method. Gd2O3 coating layers were found on the surface of the carbon fibers in these two kinds of the composites, while GdC2 precipitations were found in the hybrid reinforced composite only. Owing to this phenomenon, the coating layer in SiC+Cf/Mg-8Gd composite (88 nm) was much thinner than the one without the SiC particles (160 nm). The Gd2O3 coating layer formed on the surface of carbon fibers can improve the wettability between carbon fibers and magnesium alloy.