Characterization of Mechanical Properties and Corrosion Behaviours of Mn and Al Bronze Castings

Abstract

From ancient times to the present, copper alloys, brasses and bronzes are used for marine applications due to their high resistance to sea water. In time, numerous of copper alloys have been developed and manganese (Mn) and aluminium (Al) bronzes are the well-known members of this large family. They have superior properties and are used to produce some critical components of boats. These alloys are in competition with each other. For this reason, C86500 Mn bronze and C95800 Al bronze were evaluated in this study. Mechanical and corrosion tests were carried out on specimens which were taken from sand castings. Tensile, impact and hardness tests were applied to determine mechanical properties. Corrosion behaviour of the alloys was characterized in HCl, NaCl, and H2SO4 solutions. Additionally, microstructure observations and a definition of phases were realized. According to mechanical tests results, Al bronze has better properties than Mn bronze. Moreover, Mn bronze provides lower corrosion rates in HCl solution as Al bronze in H2SO4. Intergranular corrosion was detected in HCl solutions. Moreover, some micro shrinkage zones were seen on an Al bronze specimen after corrosion tests.