Plastic Strain Energy in Low-Cycle Fatigue of A356 (Al-7Si-0.4Mg) Aluminum Alloys
In this paper, the problem of plastic strain energy density as a evaluation of low-cycle fatigue (LCF) properties for A356 alloys with various Ti content and Ti-addition methods is considered. The experimental results reveal that it is not the Ti-addition methods but the Ti content that has played an important role in influencing on the plastic strain energy density, thus on the LCF life. Whether for the electrolytic A356 alloys or for the melted A356 alloys, the alloys with 0.1% Ti content can consume higher cyclic plastic strain energy during the cyclic deformation compared with the alloys with 0.14% Ti content due to the better plasticity, giving rise to a better fatigue resistance and a longer LCF life. Because of the different macro or micro deformation mechanism, the fracture surface of electrolytic A356 alloy exhibits the diverse microstructural morphologies under the various strain amplitude.