Mechanical and wear behaviors of Al–12Si–XMg composites reinforced with in situ Mg2Si particles

A study has been conducted to investigate the mechanical and wear behaviors of the Al–12Si–XMg alloys (where Mg contents were 5%, 10% and 20%) cast by adding modifiers such as Sr, red phosphorous and salt mixtures. Mechanical properties were determined by hardness measurements, compression and wear tests. Reciprocating wear tests were conducted by rubbing ceramic (Al2O3) and steel (AISI 52100) balls on the unlubricated surfaces by applying the normal load of 2 N. The microstructure of the Al–12Si–XMg alloys consisted of the Si needles and Mg2Si precipitates (two morphologies of which are polyhedral shape dark particles and grey colored components of Chinese script) in the Al matrix. Results demonstrated that volume fraction and size of the primary Mg2Si particles increased with increasing the Mg content. Mg containing alloys exhibited higher hardness and better wear resistance than the Mg free alloy.