Effect of non-isothermal aging on microstructure and corrosion behavior of multilayer friction surfaced Al-Mg-Si alloy with Ag additive
(Department of Materials Engineering, Babol Noshirvani University of Technology, Babol 47148-71167, Iran)
Abstract: The influence of non-isothermal aging on the microstructure and corrosion behavior of multilayer friction surfaced Al-Mg-Si alloy with different amounts of silver additive was investigated. The silver in 4, 8, and 13 wt.% was inserted into the consumable rods by drilling holes in the cross-section of the consumable rods. The coating microstructure was studied by using light and electron microscopy, the mechanical properties of the coatings were studied by using microhardness and tensile tests, and the corrosion resistance of samples was studied by using electrochemical testing. The results show that the grain size of friction surfaced layers decreases from (1.5±0.3) to (1.0±0.3) μm with increasing the silver additive content from 4 to 13 wt.%. The solute silver in the aluminum matrix increases the precipitation kinetics in the Al-Mg-Si alloy. After non-isothermal aging, the yield and tensile strengths of the silver-containing coating are 50.6% and 43.5% higher than those of the silver-free coating, respectively. Non-isothermal aging treatment reduces corrosion current density and increases corrosion resistance of both samples with and without silver additive. The corrosion resistance of the silver-containing coating after non-isothermal aging is 96.5% higher than that of the silver-free coating.
Key words: non-isothermal aging; microstructure; corrosion behavior; Al-Mg-Si alloy; silver additive; multilayer friction surfacing