We investigated the mechanical properties of -oriented square cross-sectional silicon nanowires under tension and compression, with a focus on the effect of side surface orientation. Two types of silicon nanowires (i.e., nanowires with four {100} side surfaces and those with four {110} side surfaces) were simulated by molecular dynamics simulations at a temperature of 300 K. The deformation mechanism exhibited no dependence on the side surface orientation, while the tensile strength and compressive strength did. Brittle cleavage was observed under tension, whereas dislocation nucleation was witnessed under compression. Silicon nanowires with {100} side surfaces had a lower tensile strength but higher compressive strength. The effect of side surface orientation became stronger as the nanowire width decreased. The obtained results may provide some insight into the design of silicon-based nano-devices.

Tailoring the morphology and distribution of the Al₂Ca second phase is important for improving mechanical properties of Al₂Ca-containing Mg-Al-Ca based alloys. This work employed the industrial-scale multi-pass rotary-die equal channel angular pressing (RD-ECAP) on an as-cast Mg-3.7Al-1.8Ca-0.4Mn (wt %) alloy and investigated its microstructure evolution and mechanical properties under three different processing parameters. The obtained results showed that RD-ECAP was effective for refining the microstructure and breaking the network-shaped Al₂Ca phase. With the increase of the ECAP number and decrease of the processing temperature, the average sizes of Al₂Ca particles decreased obviously, and the dispersion of the Al₂Ca phase became more uniform. In addition, more ECAP passes and lower processing temperature resulted in finer α-Mg grains. Tensile test results indicated that the 573 K-12p alloy with the finest and most dispersed Al₂Ca particles exhibited superior mechanical properties with tensile yield strength of 304 MPa, ultimate tensile strength of 354 MPa and elongation of 10.3%. The improved comprehensive mechanical performance could be attributed to refined DRX grains, nano-sized Mg₁₇Al₁₂ precipitates and dispersed Al₂Ca particles, where the refined and dispersed Al₂Ca particles played a more dominant role in strengthening the alloys.

The fracture of the Mg/Mg₁₇Al₁₂ interface was investigated by molecular dynamics simulations. The interface crack extends in a brittle manner without noticeable plasticity. The distributions of normal stress and separation along the interface were examined to render a quantitative picture of the fracture process. A normal traction–separation curve was extracted from simulation and compared with three cohesive zone models, i.e., cubic polynomial cohesive zone model, exponential cohesive zone model, and bilinear cohesive zone model. The exponential cohesive zone model exhibits the best agreement with simulation results, followed by the bilinear cohesive zone model.

Although cutting flow peanut-picking is the main peanut harvesting method, it has the problems of a large harvest loss and a high damage rate of peanut shells. The analysis of impact-friction contact characteristics during peanut fruit picking is crucial to illustrate peanut fruit picking damage. A typical peanut variety, “Dabaisha”, was considered in this study. The characteristics of peanut-picking impact-friction were studied using a peanut-picking impact-friction test bench under different conditions. An orthogonal test with three factors and levels was performed after the single-factor condition was determined. The apparent morphologies of peanut shells before and after the collision and friction tests were compared and analyzed using micro-computed tomography, white-light interferometry, and optical microscopy, whereas the impact-friction damage characteristics of peanuts under the influence of various factors were discussed. The results show that the orders of influence of the coefficient of friction of peanuts and wear loss of peanut pods were as follows: invasion depth > moisture content > contact linear velocity and moisture content > invasion depth > contact linear velocity, respectively. The experimental results and discussion in this study can provide a data reference for developing and designing peanut mechanization production equipment.

An Mg–5Sn alloy was processed by equal channel angular pressing (ECAP) for different passes (4P, 8P, and 12P), and the microstructure evolution and mechanical properties were investigated. The grain size, amount of Mg₂Sn precipitates, and texture of ECAP alloys depend on the number of passes. The ECAP 8P alloy has the finest grains and largest area fraction of Mg₂Sn particles, followed by the ECAP 12P alloy. The ECAP 4P and 8P alloys exhibit basal textures tilted towards transverse direction (TD), whereas the ECAP 12P alloy shows basal texture with the c-axis of the grains parallel to the extrusion direction (ED). ECAP alloys show superior strengths compared to the as-cast alloy, mainly attributed to fine grain strengthening, precipitation strengthening, texture strengthening, and dislocation strengthening. The ultimate tensile strength (UTS) increases while the elongation (EL) decreases with increasing ECAP pass.

A Mg-5Sn alloy was hot rolled at 380 °C with three different rolling reductions (30%, 50%, and 70%), and its effect on the microstructure and mechanical performance was examined. Grain size decreases, whereas the area fraction of Mg₂Sn particles and dislocation density increase with the increase in rolling reduction. Therefore, the yield strength (YS) and ultimate tensile strength (UTS) exhibit an ascending trend, whereas the elongation (EL) shows a descending trend with increasing rolling reduction. The alloy hot rolled for 70% possesses a high strength of 310 MPa and an EL of 8.4%. The strength enhancement is mainly ascribed to precipitation strengthening, grain refinement strengthening, and dislocation strengthening.