Institute of materials and machine mechanics Slovak Academy of sciences

The study and modeling of mechanical and tribological characteristics of novel ultra-finegrained Al-Al2O3 composites


Acronym:SAPLIKE
Project start:01.01.2012
Project end:31.12.2014
Programme:Academic agreement
Project number:SAS-NSC JRP 2011/06
Institute position in the project:Project co-lead partner
Project leader at the institute:Martin Balog
Aluminium alloys are widely applied in transport and precision machine industry mainly due to their high specific strength and light-weight. In this project, a team composed of researchers from Slovak Academy of Science and National Chung Cheng University of Taiwan were cooperated to develop ultrafine-grained Al-Al2O3 composites; and investigate the critical parameters of processing route that could effect on the mechanical strength as well as tribological performance of Al powder compacts. The study conducted experimental testing and theoretical modelling to investigate ultrafine-grained Al-Al2O3 composites related to mechanical properties, high strain rate deformation and tribological performances. In this project, ultrafine-grained Al-Al2O3 composites with four different fine atomised Al powders were consolidated to study the effect of characteristics on mechanical properties of compacts and their thermal stability. A micro-force impact tester with environmental thermal control system (up to 150°C) was set up in this research for testing high rate force-displacement curves under different impact speed. A numerical method that coupled genetic algorithm with FEM was used to reverse finding the constitutive model of Al compacts with strain rate and temperature effects. The constitutive model was coupleed into ABAQUS software to examine the energy absorbing performance of machine components such as aluminium steering wheel and CNC components. A lateral force measurement technique attached to a nanoindenter system has proven to be one of the best ways of evaluating the scratch resistance, in which scratching at different locations at constant load can be used to investigate Al-Al2O3 composites quality and homogeneity. The nanowear procedure consisted of sequential constant load scratches over the same track, with a low load topography measurement performed between each scratch, in which can be used to determine the friction and lubrication of Al powder compacts. Moreover, the tribological performance including coefficient of friction, wear, surface temperature and surface hardened layer were evaluated using a tribo-meter and energy dispersive X-Ray spectroscopy (EDXS). Test conditions included a wide array of geometry configuration, loading and relative speed for the evaluation of industrial applications. In addition, the mechanical properties data were then input to a suitably trained artificial neural network (ANN) in order to inversely derive the corresponding critical parameters of processing route such that the mechanical properties of the Al compact could be extracted. Through this proposed research, the processing route that influence the mechanical properties, high rate deformations, and tribological performances were thoroughly investigated so that a novel ultra-fine grained Al-Al2O3 composite could be proposed to utilize in many industrial applications.