Comparison of tribological characteristics of LM13/B4C and LM13/ilmenite composites at high temperature conditions

Abstract

Abstract In this work, high temperature tribological characteristics of ilmenite reinforced LM13 aluminium alloy based composites (AMCs) and boron carbide reinforced AMCs are compared. Stir-cast composites were processed using boron carbide (CDP) and ilmenite (NDP) particles separately as reinforcements. Particle size range was 106–125 μm and reinforcement levels were 5, 10, and 15 wt.% for both types of composites. Both composites exhibited uniform distribution of reinforced particles and grain refinement. Compared to the LM13 base alloy, NDP composite containing 15 wt.% reinforcement showed significant improvement in hardness (57%), coefficient of friction (57%), mild-to-severe wear transition temperature, average steady-state wear rate (49%), and coefficient of thermal expansion (55%). CDP-15 composite showed slightly better properties than NDP-15 composite. Microstructure refinement, increased dimensional stability, formation of oxide layer, and formation of tribo-layer due to reinforcement of the ceramic fillers were the main reasons for improvement in properties of processed AMCs. SEM-EDS of wear tracks-debris showed abrasive/delamination wear as the main mechanisms for materials loss. The research showed that the low-cost ilmenite particles can substitute for the very costly boron carbide particles as reinforcements in AMCs used for dry sliding wear applications under high operating temperatures-applied load conditions of the order of 300°C-49 N.