The response of boronized 34CrAlMo5-10 (EN41B) steel to nanoindentation, oxidation, and wear

Abstract

The present study deals with the properties of boronized and non-boronized low-alloy steel (34CrAlMo5-10). Specimens are characterised using microscopy, various spectroscopic techniques, nanoindentation, surface profilometer, and tribometer. The boronized region contains (i) (Fe, M)2B columns and (ii) matrix between the columns. Nanoindentation study reveals the difference in the mechanical behaviour of boride, matrix, and core regions. Strain-rate sensitivity of different regions of the specimen cross-section varies between 0.005 and 0.011. The boride phase is more sensitive to the strain-rate than matrix and core. The room-temperature oxidation resistance of the steel surface is enhanced by the presence of a higher proportion of mixed-boride and the oxide layer enriched with Cr2O3. At 550 and 850°C, boronized specimens have higher oxidation resistance than the non-boronized specimens, where the layer of iron-borates protects the surface. At 200°C, the boronized specimen has deprived oxidation resistance. Amongst the investigated wear-parameters, the maximum and minimum wear-resistance of the boronized surface is about 46 and 8 times the wear-resistance of the non-boronized surface, respectively. A steeper drop in the tribological advantage gained by the boronizing treatment is perceived with the increase in load, especially under higher sliding speed. © 2020 Informa UK Limited, trading as Taylor & Francis Group.