Experimental investigation of tensile fractography and wear properties of Al-12.5Si alloy reinforced with ZrO2 using spray deposition method

Abstract

To improve the wear resistance of Al–12.5Si alloy, various percentage of zirconium oxide as reinforcement particles were used to produce metal matrix composites by spray deposition method. First, the developed metal matrix composites were subjected to dry sliding wear test using pin-on-disk apparatus under 60 N normal load with sliding velocity of 4.5 m/s at room conditions (∼28 °C and ∼60% relative humidity). The experimental results showed that the wear resistance of the developed composite can be optimized using a proper flight distance. In order to model the correlation between the wear properties and applied load, flight distance and sliding velocity of the metal matrix composites, a neural network model with genetic algorithm was developed. Second, the spray forming parameters such as flight distance, gas pressure, melt temperature and ZrO2 reinforcements were examined experimentally and analyse the insight on mechanical properties. Central composite design (CCD) with response surface methodology (RSM) was employed for selecting experimental matrix and latter perform detailed analysis. ZrO2 reinforcements and gas pressure showed major contribution, whereas negligible contributions with melt temperature and flight distance on hardness and UTS. The developed non-linear models for both responses showed similar effects and confirmed their relationship appears linear with good correlation coefficient equal to 0.978. The non-linear models derived empirical equations ensures accurate prediction with ten experimental cases equal to 1.21% for hardness and 6.09% for UTS, respectively. Multiple objective particle swarm optimization based crowding distance (MOPSO-CD) method integrated with desirability function approach (DFA) to determine the optimal spray forming conditions for achieving maximum hardness and UTS. The weights (0.05 for hardness and 0.95 for UTS) which ensures highest desirability value equal to 0.9958, and corresponding optimal spray forming conditions (melt temperature: 798 °C, flight distance: 0.35 m, gas pressure: 0.97 MPa and ZrO2 reinforcements: 11.6%) resulted in highest hardness of 80.4 HV and UTS of 173.2 MPa, respectively.