Effect of alloying elements on microstructure of aluminum-based piston alloys: experimental and simulation studies

The present study provides a comparison of three piston alloys (Al-Si-Cu-Mg-Ni). Microstructures were examined by optical microscope (OM), optical emission spectrometry (OES), x-ray diffraction (XRD) and Brinell hardness test in order to investigate the chemical composition, microstructure, phases and hardness, respectively. Quantometric results showed that chemical compositions of pistons are in 3xx.x range. Results indicated that silicon in the microstructure of pistons is in bar, eutectic and polygonal shapes which represents the hypo-eutectic, hyper-eutectic and eutectic Al-Si alloys. In addition, different phases were characterized based on their shapes. The results of Brinell hardness test indicated that the sequence of hardness is as follows: Alloy 1 > Alloy 3 > Alloy 2 which is because of the hard phases and the value, size and dispersion of silicons. Likewise, graphical simulations using Finite element method (FEM) were executed for these alloys, representing different Von Mises stress, pile-up displacement, and dimeter of indentation.

Keywords:

piston alloy , microstructure , silicon , hardness , simulation