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The thixomolding technology offers distinct advantages for producing magnesium matrix composites with intricate geometries. This study explores the effects of incorporating hybrid SiC–Al2O3 particles on the microstructure, deformation, fracture, and mechanical properties of a thixomolded Mg–10Zn alloy. The composite exhibits a homogeneous distribution of Al2O3 and SiC particles within the matrix. The addition of SiC–Al2O3 reinforcements helps reduce the content of primary α -Mg solid and refine the microstructure. The composite demonstrates a yield strength of 186 MPa, an elastic modulus of 48.6 GPa, and a respectable elongation of 6.8%. The digital image correlation measurement was performed at the sample scale, unveiling overall deformation characteristics. Crystal plasticity finite element method was employed for high-fidelity microstructure, showcasing mesoscale deformation feature such as the deformation mechanism of grains adjacent to reinforcements. It was found that SiC–Al2O3 particles prevent the formation of large shear band, benefiting the ductility of the material. The post-mortem analysis using scanning electron microscope near the fracture position reveals micro-cracks inside the SiC particles. Notably, the SiC/Mg interface shows no signs of cracking, while some Al2O3/Mg interfaces are separated. Reinforcement cracking is correlated to the stress it withstands, and the mesoscale deformation analysis reveals that the reinforcement stress is increased when non-basal slip in grains adjacent to the reinforcement becomes difficult to be activated. This work serves as an example for developing Mg matrix composites through the thixomolding process. The findings of this study provide valuable insights for the design of high-performance thixomolded Mg-based composites [ABSTRACT FROM AUTHOR]

Single crystal particle morphologies have become highly desirable for next generation cathode materials, removing grain boundary fracture and thereby reducing the surface area exposed to electrolyte. The intrinsic mechanical behavior of single crystal layered oxides, however, is poorly understood. Here, faceted single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811) particles are compressed in situ in a scanning electron microscope (SEM), to determine mechanical deformation mechanisms as a function of crystallographic orientation. In situ, the dynamical deformation sequence observed is initial cracking at the compression zone, followed by accelerated transparticle crack propagation and concurrent (0001) slip band formation. The greatest loads and contact pressure at fracture, non‐basal cracking, and activation of multiple basal slip systems in larger (>3 μm) particles, occur for compression normal to the (0001) layered structure. Loading on {012} preferentially activates basal fracture and slip at lower loads. Regardless of particle orientation, non‐basal slip systems are not observed, and non‐basal cracking and particle rotation occur during compression to compensate for this inability to activate dislocations in 3‐dimensions. Crystallographic dependent mechanical behaviour of single crystal NMC811 means that particle texture in cathodes should be monitored, and sources of localised surface stress in cathodes, e. g. particle‐to‐particle asperity contacts during electrode manufacture, should be minimised. [ABSTRACT FROM AUTHOR]

Three types of layered‐hybrid lattice structures (LHLSs) with different layer thicknesses composed of body‐centered‐cubic (BCC) and face‐centered‐cubic (FCC) unit cells are designed and manufactured by selective laser melting using Ti–6Al–4V powder. The microstructure and surface morphologies of the three types of the selective laser melting‐formed LHLSs are examined by an optical microscope and scanning electron microscope (SEM), respectively. Quasistatic compression experiments are carried out to investigate the mechanical properties. The results show that the layer thickness has a significant effect on the mechanical properties and deformation behaviors. The elastic modulus, yield strength, and ultimate compressive strength of LHLS increase with the increasing BCC and FCC layer thickness, respectively. Based on the observations of deformation process, a 45° shear band and axial fracture are observed in LHLS‐8, and step‐like deformation bands are observed in both LHLS‐4 and LHLS‐2 samples. Besides, the influence of different loading directions on mechanical properties is also investigated; it is found that the ultimate compressive strength loaded in the transverse direction is independent of the layer thickness in LHLSs. [ABSTRACT FROM AUTHOR]

For the purpose of investigating the microstructure deformation of 28Mn-10Al-C steel at high speeds under different strain rates, the dynamic properties of 28Mn-10Al-C steel under varying strain rates and the feasibility of the tensile specimens with a variable cross-section were evaluated using a combination of tensile test, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), and electron back scatter diffraction (EBSD). The test results demonstrate that the high-tension tensile process of 28Mn-10Al-C steel involves a competitive process of work hardening, deformation speed reinforcement, and adiabatic temperature elevation. The elasticity limit, tensile strength, and elongation of 28Mn-10Al-C steel increase with the rate of deformation. Specifically, at a deformation rate of 103 s−1, the yield strength, tensile strength, and elongation of the test steel increase to 817 MPa, 1047 MPa, and 60.6%, respectively, indicating significant improvements in all properties. Through analyzing its mechanical properties, dislocation density, and angle grain boundary density, this article discusses the deformation behavior of 28Mn-10Al-C steel during dynamic deformation. It is found that the dominant hardening mechanism and softening mechanism in the deformation process change with the increase in strain rate. [ABSTRACT FROM AUTHOR]

Titanium alloys are widely employed in aerospace applications due to an outstanding combination of properties. The variety of loading conditions and microstructures encountered in industrial components is urging the development of microstructure sensitive modeling capabilities. In particular, reliable predictions require a good knowledge of operating deformation mechanisms. The present study aims at providing a thorough characterization of deformation mechanisms in the near-α Ti-6Al-2Sn-4Zr-2Mo alloy using experiments and simulations. The sequential activation of deformation mechanisms in the α phase was monitored in situ during a tensile test carried out in a scanning electron microscope using a combination of slip traces analysis and electron back-scattered diffraction. Basal slip is activated first, and prismatic slip activity, which proceeds at a higher macroscopic stress level, is needed for a significant creep/relaxation to occur. While little evidence of 〈 a 〉-type pyramidal slip was found, 〈 c + a 〉 pyramidal slip involved first-order pyramidal planes and operates at stress levels near or above the 0.2% proof stress. Atomic force microscopy characterization of the features of the different slip modes revealed that 〈 a 〉 slip is coarser and wavier than 〈 c + a 〉 slip. Twinning, which is usually neglected in such alloys within this strain regime, was observed to be slip stimulated at a plastic strain as low as 0.5%. Crystal plasticity parameters leading to an accurate simulation of the activation sequence of deformation mechanisms were then determined. For this purpose, critical resolved shear stress values were derived for the different slip and twinning modes using specific approaches and subsequently validated using crystal plasticity simulations based on fast-Fourier transforms. [ABSTRACT FROM AUTHOR]