Abstract: Aluminium alloys of 5xxx and 6xxx series are commonly used in marine environment due to their good corrosion resistance. 6xxx series alloys show better mechanical properties and good weldability but have comparatively less corrosion resistance. Alloy 6082 has highest strength among 6xxx series, which can be further increased to get peak strength by T6 tempering. Also it has high corrosion resistance due low copper content. Second phase particles formed during precipitation hardening heat treatment gets randomly distributed throughout the grains and helps to increase hardness and corrosion resistance of metal. In this study various experiments of precipitation hardening are done on aluminium alloy 6082-T6 to increase its hardness and corrosion resistance. Effect of time and temperature of solution heat treatment and artificial aging on the hardness and corrosion resistance of alloy is analyzed. Also effect of temperature of corrodent on corrosion behavior is determined. Hardness is measured on Rockwell E scale. Immersion corrosion test is carried out to find general corrosion resistance. Microstructures of hardened as well as corroded samples are analyzed by means of optical microscopy. The results show that during precipitation hardening process, the grain size and grain structure changes; both of which are responsible for change in hardness. Hardness increases with increasing artificial aging time up to 12 Hrs. It is also observed that corrosion resistance of alloy is not only dependent on chemical composition and grain structure of exposed alloy but also on composition of corrodent (e.g. pH, temperature, halide concentration, velocity, aeration). The increase of hardness and corrosion resistance increases alloy strength and life in sea water.
 
Key words: 6082-T6 Al alloy, hardness test, immersion corrosion test, precipitation hardening.

Cite: Aditya R. Prabhukhot, "Effect of Heat Treatment on Hardness and Corrosion Behavior of 6082-T6 Aluminium Alloy in Artificial Sea Water," International Journal of Materials Science and Engineering, Vol. 3, No. 4, pp. 287-294, December 2015. doi: 10.17706/ijmse.2015.3.4.287-294