Surface structural features and wear analysis of a multilayer Ti6Al4V-B₄C thin film coated AISI 1040 steel

Abstract The deprived wear resistance of AISI 1040 steel often results in higher wear rates. The best ways to upgrade their wear resistance are to introduce hard particle reinforcement to produce a metal matrix composite which can be used as a coating. In the present study Ti-6Al-4V-4B₄C metal matrix composite coatings were coated on AISI 1040 steel using the magnetron sputtering process and their dry sliding wear behavior was studied at room temperature. The coating morphology was explored by SEM, XRD, FT-IR, and AFM. The constant coating thicknesses of 80 nm and 115 nm were achieved for 0.5 h and 1 h coating duration, respectively. The effects of introducing B₄C on the hardness, thermal behavior, wear, and friction characteristics were studied. The nano hardness and elastic modulus were attained by AFM nanoindentation technique which showed a maximum of 21.7 GPa and 218.4 GPa, respectively. It was proven that the adding of B₄C increases the thermal stability of Ti-6Al-4V-4B₄C coatings as well as modifies the oxidation mechanism. It is expected that the addition of B₄C will improve the thermal behavior of thin film coatings for their practical application. Wear tests were executed by ball-on-disc wear tester with E-52100 sphere as the counterface at a sliding velocity of 2 m s⁻¹ with 3 N load. Wear rate and coefficient of friction (CoF) reduced with an increase in load and sliding distances also composite coatings exhibited higher wear resistance within entire loading conditions, hereafter suggesting that it could be a favorable substitute to other hard coatings.