Effect of porosity on dry sliding wear of Al–Si alloys

Porosity adversely affects the pressure tightness (ability of a system to hold pressure), mechanical properties and wear resistance of components. The amount of porosity and the size and shape of pores have a great impact on material removal during wear. Al–Si alloy with different porosity levels was prepared using powder metallurgy technique. Dry sliding wear behavior was investigated against AISI 52100 bearing steel ball. It was found that the wear rate gradually rises with surface porosity, then drops as porosity and pore size reach critical levels. A model was developed to explain the relationship between porosity and pore size.

Research highlights►High pressure die cast Al–Si based alloys suffer from surface porosity. ►Surface and subsurface porosity in castings accelerate delamination wear. ► A strong correlation exists between wear rate and pore size.