The tensile creep behavior of an equiatomic CoCrFeNiMn high-entropy alloy was systematically investigated over an intermediate temperature range (500–600 °C) and applied stress (140–400 MPa). The alloy exhibited a stress-dependent transition from a low-stress region (LSR-region I) to a high-stress region (HSR-region II). The LSR was characterized by a stress exponent of 5 to 6 and an average activation energy of 268 kJ mol⁻¹, whereas the HSR showed much higher corresponding values of 8.9–14 and 380 kJ mol⁻¹. Microstructural examinations on the deformed samples revealed remarkable dynamic recrystallization at higher stress levels. Dislocation jogging and tangling configurations were frequently observed in LSR and HSR at 550 and 600 °C, respectively. Moreover, dynamic precipitates identified as M₂₃C₆ or a Cr-rich σ phase were formed along grain boundaries in HSR. The diffusion-compensated strain rate versus modulus-compensated stress data analysis implied that the creep deformation in both stress regions was dominated by stress-assisted dislocation climb controlled by lattice diffusion. Nevertheless, the abnormally high stress exponents in HSR were ascribed to the coordinative contributions of dynamic recrystallization and dynamic precipitation. Simultaneously, the barriers imposed by these precipitates and severe initial deformation were referred to so as to increase the activation energy for creep deformation.

A numerical study on the indentation and scratch responses of epoxy (EP) and its composites using finite element modeling is presented. This work is motivated by previous experimental results [1 Z.Z. Wang, P. Gu, Z. Zhang, L. Gu, and Y.Z. Xu, Mechanical and tribological behavior of epoxy/silica nanocomposites at the micro/nano scale, Tribol. Lett., vol. 42, pp. 185–191, 2011.[Crossref], [Web of Science ®] [Google Scholar]], which show that the addition of silica nanoparticles can obviously increase the hardness and modulus and improve the scratch-resistance of the EP matrix. Simulation results are compared with these experimental ones and show very close agreements. The modification mechanisms of the nanoparticles are also presented. Stress analysis demonstrates that the load transferring from matrix to particles is the direct strengthening mechanism.

A polypropylene nanofibrillar array was successfully fabricated by template-assisted nanofabrication strategy. Adhesion properties of this gecko-inspired structure were studied through two parallel and independent approaches: experiments and finite element simulations. Experimental results show relatively good normal adhesion, but accompanied by high preloads. The interfacial adhesion was modelled by effective spring elements with piecewise-linear constitution. The effective elasticity of the fibre-array system was originally calculated from our measured elasticity of single nanowire. Comparisons of the experimental and simulative results reveal quantitative agreement except for some explainable deviations, which suggests the potential applicability of the present models and applied theories.