On the tribological behavior of nanoalumina reinforced low alloy sintered steel

• A novel process has done to ameliorate wear resistance.
• We examine changes in the level of porosity by adding alumina nanoparticles.
• Effect of load on tribological behavior of metal matrix composite has investigated.
• By adding alumina nanoparticles, volume loss decrease up to 73%.
• Wear mechanisms have studied completely.

Powder metallurgy (PM) technique offers progress of new material processing for applications requiring various combinations of properties. Demanding for applying ceramic materials in tribological concept is increasingly growing over last two decades. Unique characteristic of ceramic materials such as low density, high hardness, low thermal expansion, high corrosion and tribological resistance is the rudimentary reason. In this study, different weight percentage of alumina nanoparticles was added to low alloy powder steel (Astaloy 85Mo) as reinforcement agent. Microstructure and tribological behavior of the metal matrix composite has investigated at dry condition and room temperature for different loads by reciprocating tribometer. Sintered specimens possess homogenous microstructure with bainitic and partial ferrite feature in retained austenite matrix. Outcomes show improvement in wear resistance by increasing of alumina nanoparticles containing 3 wt.%, porosity level of 15.38% and micro hardness of 105.4 HV which demonstrates the best wear resistance properties. Tribological behavior of PM steel parts is so complex due to existing pores. Not only do surface pores deteriorate the wear resistant as inherent characteristic but also the properties could enhance at optimum porosity level. An important role of surface porosities which have crucial influence on decreasing wear rate is trapping wear debris causes severe wear. Mixed mode of abrasive, adhesive and oxidation mechanisms were distinguishing according to electron image analysis.