Fabrication of heat-treated nano-clay-composite for improving high-cycle fatigue properties of AlSiCu aluminum alloy under stress-controlled fully-reversed bending loads

Abstract

In the present article, a heat-treated nano-clay-composite was fabricated by stir-casting to improve high-cycle bending fatigue properties of AlSiCu aluminum alloys, which have been widely used in engine cylinder-heads. For such an objective, after ball milling of nano-clay-particles with micro-copper-particles, these coated particles were added to the aluminum melt and cylindrical specimens were stir-casted. Then, fully-reversed stress-controlled fatigue testing was performed on standard samples. In addition, the fracture surface was examined by the field-emission scanning electron microscopy to find failure mechanisms. Obtained results showed that reinforcements, including nano-clay-particles and the heat treatment increased the fatigue lifetime, at least 9%. Such an improvement in the fatigue lifetime was 125% under low values of the stress level. Due to have a proper distribution of nano-particles in the aluminum matrix, the scatter-band for the fatigue lifetime was narrower in the heat-treated nano-composite. The endurance fatigue limit was also improved 30% at 106 cycles, for the heat-treated nano-composite, comparing to the base material. The brittle fracture was observed due to have cleavage and quasi-cleavage marks on the fracture surface for both materials. Micro-cracks were initiated and propagated from Si and intermetallics phases.

Bending cyclic behavior and scatter-band analysis of aluminum alloys under beneficial and detrimental conditions through high-cycle fatigue regime

“…Increasing the fatigue lifetime of aluminum alloys by the reinforcement was also reported by Rezanezhad et al [10], Sharifi et al [13], and Khisheh et al [14], which could be claimed as an agreement with obtained results in this research. The reason for such an improvement was due to the microstructural changes in the microstructure of the aluminum alloy.…”

“…More details for the fabrication of the studied materials could be found in the literature by Aroo et al [1], Azadi et al [3], Rezanezhad et al [10], and Zolfaghari et al [11]. In addition, more details of fatigue testing and the geometry of standard cylindrical samples could be followed in the literature by Parast et al [12], Sharifi et al [13], and Khisheh et al [14]. After testing, a regression curve-fitting process was done for the sensitivity analysis on experimental data.…”

Corrosion Effects on High‐cycle Fatigue Lifetime and Fracture Behavior for Heat‐treated Aluminum‐matrix Nano‐clay‐composite Compared to Piston Aluminum Alloy

“…More details of these microstructures including FE-SEM images were found in previous studies [1,3]. Azadi et al [17,38] and Shari et al [53] showed that by the presence of the reinforcement (nano-particles plus the heat treatment), the change in the Si morphology was signi cant and seemed to be the needle-shape and also the block shape. Due to the reinforcement, the Si phase percentage enhanced as 8%.…”

“…As a rst statement, the brittle fracture was seen according to the presence of cleavage and quasi-cleavage marks in all specimens under fatigue and corrosion-fatigue tests. Moreover, tear ridges, micro-cracks, and also broken intermetallics phases were also observed on the fracture surface of specimens, as also represented in the literature [13,[53][54]. As Zhang et al [55] reported, when there was a brittle facture behavior in the material, the fatigue fracture of the piston aluminum alloy happened in a perpendicular direction to the force axis.…”