An evaluation of tribological and mechanical properties of Al-Si-Cu alloy with nano-clay particles reinforcement

Abstract

In this paper, comparative evaluations on the mechanical properties of Al-Si-Cu alloy reinforced by nano-clay mineral particles were carried out. Such nano-composites contained 1 wt% nano-clay particles and were manufactured through the stir casting with various stirring temperatures and times. Mechanical behaviors such as the hardness and compressive strengths, the elastic modulus and wear properties were studied. The microstructural observations were conducted by the optical and the scanning electron microscopy. Field emission scanning electron microscopy (FESEM) images showed that nano-clay particles distributed uniformly in the aluminum matrix for the nano-composite fabricated at 800 ℃ and was stirred for 2 min. Besides, the lower stirring temperature of 750 ℃ caused a degree of clustering with a size of lower than 200 nm in some places. In comparison with the base alloy, an improvement of 5% to 33% in Brinell hardness value observed for various nano-composites. The wear resistance of various nano-composites also increased two to five times regarding the base alloy. The parameter of µ/E. H2 would predict the wear rate for all specimens. It was found that nano-composites fabricated at the temperature of 750 ℃ exhibited the lower porosity content and the higher ultimate compressive strength, and the elastic modulus.

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

“…31 The nano-particles size was between 20 and 30 nm, which was proven in the literature. 32,33 It should be noted that the weight percentage of nanoclay-particles (Montmorillonite K10 created by Sigma-Aldrich Chemie GmbH) was 1% in the aluminum melt, during stir-casting, according to the literature. [32][33][34][35][36][37] It should be mentioned that the major percent of nano-clay-particles was 51% of SiO 2 and 20% of Al 2 O 3 , 6% of Fe 2 O 3 , 3% of MgO, 2% of CaO, 1% of Na 2 O, 1% of K 2 O, 1% of TiO 2 and the rest was LOI.…”

“…This process was repeated 3 times and the hold time between each repeat was 15 min. 32,33,35 More details for such a process were described in the literature. 34,35 The process quality of ball milling was proved by the SEM image, depicted in Figure 1.…”

“…To have a better melt, degassing and preheating of the mold were done. The melt temperature in casting was selected as 750 C. 32,33,46 Then, initial cylinders were machined based on the dimension of standard samples for HCF testing. For the nanocomposite, the stir-casting process was used.…”

“…The melt temperature in stir-casting was selected as the same as the casting method. 32,33,46 To find distribution of nano-clay-particles in the aluminum matrix, Figure 2 is presented including the field-emission scanning electron microscopy (FESEM), the Tscan model. Figure 2 shows a proper distribution of nano-clay-particles in the aluminum matrix.…”

“…Comparing to the size of 20-30 nm of initial nano-particles before stir-casting; therefore, no agglomeration of nano-clay-particles could be observed after the fabrication of nano-composites, based on the literature. 33,37,46 It should be again noted that the weight percent of nano-particles was 1% in the aluminum matrix. As an expectation, if the distribution of nano-particles was not proper; then, the fatigue lifetime decreased.…”