Design and Optimization of Microstructure for Improved Corrosion Resistance in Laser Surface Alloyed Aluminum with Molybdenum

摘要

The in-situ measurement of dilution during the laser surface alloying process is an enormously difficult task, due to the localized nature of laser energy and very short laser-material interaction time. Therefore, a computational approach (finite-element method and analysis of variance) was effectively employed to evaluate the dilution during the laser surface alloying process. Firstly, a finite-element model based on COMSOL multiphysics was developed to predict the dilution of Mo with Al during non-equilibrium laser surface alloying process. Secondly, the optimization model based on Design-Expert was developed to find the optimal laser surface alloying parameters (laser power, scanning speed, and fill spacing) to obtain a microstructure suitable for improved corrosion resistance that is primarily attributed to the formation of Al_5Mo intermetallic phase (16.7 at% Mo). The present optimization model utilized the prior experimental and computational (finite-element) modeling data for the concentration of Mo (at%). The optimization analyses were carried out for the all the current datasets and the analysis revealed 44 optimal solutions that indicate the highest desirability. The confirmation runs were carried out to validate the optimization model. The experimental observation showed that the sample processed with optimal processing conditions demonstrates good corrosion resistance.