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2014) Effects of particle/matrix interface and strengthening mechanisms on the mechanical properties of metal matrix composites, Composite Interfaces, 21:5, 415-429, A randomly distributed multi-particle model considering the effects of particle/matrix interface and strengthening mechanisms introduced by the particles has been constructed. Particle shape, distribution, volume fraction and the particles/matrix interface due to the factors including element diffusion were considered in the model. The effects of strengthening mechanisms, caused by the introduction of particles on the mechanical properties of the composites, including grain refinement strengthening, dislocation strengthening and Orowan strengthening, are incorporated. In the model, the particles are assumed to have spheroidal shape, with uniform distribution of the centre, long axis length and inclination angle. The axis ratio follows a right half-normal distribution. Using Monte Carlo method, the location and shape parameters of the spheroids are randomly selected. The particle volume fraction is calculated using the area ratio of the spheroids. Then, the effects of particle/matrix interface and strengthening mechanism on the distribution of Mises stress and equivalent strain and the flow behaviour for the composites are discussed.

Aiming at the problem that temperature filed changes can lead to edge cracks emerge to Al-Si alloy 4004 in the process of hot rolling, in this paper, finite element model of temperature field variations in the process of rolling have been established by the method of finite element numerical simulation. The relationship between temperature field variations and edge crack defects has been analyzed. The results show that temperature field of rolled piece is gradient variations, low in the center and high in the edge, metal accumulation in the edge, leading to stress concentration and forming cracks source, resulting in edge cracks arising in edge of roller piece. Finally, the reliability and accuracy of the numerical simulation method have been verified by hot-rolled tests and tensile tests. All the studies provide ideas for theoretical analysis of temperature variation during hot rolling and have important significance on improve the quality of products.

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