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  • Low-cycle fatigue propertie...
    Wang, M.; Pang, J.C.; Li, S.X.; Zhang, Z.F.

    Materials science & engineering. A, Structural materials : properties, microstructure and processing, 09/2017, Letnik: 704
    Journal Article

    The influences of temperature on the microstructure evolution, tensile properties, especially low-cycle fatigue (LCF) behaviors and damage mechanisms of Al-Si piston alloy have been investigated in this paper. The results show that the alloy exhibits cyclic softening at high-temperature. Fatigue cracks usually initiate from primary silicon phase and preferentially grow along particles in a slightly zigzag path at relatively low temperature. With temperature increasing, however, the ductile tearing fracture through micro-cracks can be found. In order to evaluate the fatigue life, considering the temperature and loading conditions, a comprehensive 3-parameter model based on hysteresis energy has been proposed; at a constant temperature the fatigue life can be controlled by two parameters, i.e., the intrinsic fatigue toughness W0 (the resistance to crack propagation) and the fatigue cracking exponent β (the resistance to fatigue cracking), which dominate the LCF damage mechanisms (from fatigue-induced particle cracking to rapid fatigue crack growth). For the current Al-Si alloy, the combined effect of W0, β and temperature T can lead to an optimal fatigue life at a critical temperature. This model provides a new clue for optimizing and designing the high-temperature materials.