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The results of quasi-static tensile experiments on the 20%(volume fraction) SiCp/2009Al composite show a significant dispersion of the mechanical properties such as failure strain. The effects of two uncertainties on macroscopic mechanical properties of the composite were investigated using a multiscale finite element approach. The distribution characteristics of failure strain and fracture energy, and their correlations were obtained from FE simulations of a series of mesoscale RVE models. Then combined with the macroscale model, the randomness of mechanical properties in various regions within the actual material can be characterized. The results of the quasi-static tensile simulations of the macroscale model show good agreement with the experimental results, and are also able to simulate the dispersion behavior of failure strain very well due to the introduction of material stochasticity. more...

As a classic in-situ reaction, the Al-TiO2 reaction is expected to prepare aluminum matrix composites with high thermal stability. In this study, it was found that the preparation method of ensuring sufficient reaction using higher temperatures in previous studies was not conducive to acquiring optimized high-temperature strength. With the increase of hot-pressing temperature and the extension of holding time, the in-situ reaction became more thorough, but the strength of the composites first increased and then decreased. Coarsening of the microstructure at high temperatures would lead to degradation of strength and controlling the in-situ reaction process by the hot-pressing parameters could optimize the mechanical properties of the composites. Strengthening mechanisms at room and high temperatures were studied, and it was found that the load-transfer and Orowan strengthening mechanisms are the main strengthening effects at room temperature, while the pinning effect of fine particles became more crucial at elevated temperatures. As a result, the coarsening of the reinforcing phases was more detrimental to the high-temperature strength. Therefore, an insufficient in-situ reaction led to more excellent mechanical properties, and the composite hot-pressed at 605°C and held for 2 h exhibited the highest strength, which was 367 MPa at room temperature and 170 MPa at 350°C. [ABSTRACT FROM AUTHOR] more...