The corrosion of aluminum matrix composite <i>in situ</i> based on Al–7Si–1Fe alloy

Abstract

The results of a comparative research into the corrosion resistance of an aluminum matrix composite material produced by the oxygen lancing of a prehydrogenated aluminum alloy melt based on Al–Si–Fe with an iron content of over 1.0% and Al–7% Si alloy with an iron content of up to 0.3% modified by ligature 5Al–Ti for 2% are shown. The aluminum-alloy corrosion was conditioned by the film discontinuity of the oxide on some phases, primarily Al5SiFe. The composite and reference alloy-sample couples with a diameter of 15 mm and a length of 50 mm were put to the test in a 7% solution of NaCl salt fog in SFC-1 chamber on suspension brackets at a temperature of 22°C for 300 h. The results show the mass loss close values of the samples, despite the significantly higher iron content in the composite, because particles 100–200 nm in size formed in the melt by lancing are deposited on the composite phase boundaries, reducing the interaction surface area with the corrosive environment. The researched composite material can be recommended as a corrosion-resistant alternative to alloys with elevated iron content, which are used for high pressure die casting (HPDC).