No abstract

No abstract

In this article, the low cycle fatigue(LCF) behavior of a low silicon cast aluminum alloy Al-3.5Si-0.5Mg-0.4Cu with T6 treat-state at room temperature is investigated by extracting samples from aluminum steering knuckles. Initial microstructure, cyclic stress response behavior and fatigue fracture are studied. Low cycle fatigue experiment results and behavior performance of 6 different total strain amplitudes are included. OM, SEM, XRD and TEM are carried out to observe pre(post)-fatigue microstructures and fracture. The results demonstrate that cracks initiate from surface or subsurface defects and higher total strain amplitude leads to larger sum area of fatigue crack initiation region and steady crack propagation region, and wider fatigue striation bandwidth. Furthermore, crack propagates along the interface between eutectic silicon and α-Al under low strain amplitude while crack grows through eutectic silicon particle if higher strain amplitude is applied.

In this study, the mechanical and biocorrosion behavior of as-cast Zn-xCu-0.1Sr (x = 1, 2, and 3wt%) alloys for potential application was studied. The microstructure, mechanical properties, and in vitro degradation of Zn-xCu-0.1Sr alloys were investigated. The results show that as Cu content increased from 1.0 to 3.0wt%, the number of CuZn5 phases increased and the average grain size of CuZn5 phases increased from 6.96 μm to 10.92 μm. The 2wt% addition of Cu resulted in the best mechanical properties with 129.4 MPa in ultimate tensile strength and 108.4 MPa in yield strength. Furthermore, the higher corrosion rate was experienced in the alloys with higher Cu content after immersion. Zn-xCu-0.1Sr alloys all presented appropriate in vitro degradation rates in a basically uniform degradation mode. The strength, ductility and biocorrosion property exhibited by the Zn-2Cu-0.1Sr alloy compositions make it a promising candidate for cardiovascular stent applications.