Wear performance of boron and carbon alloyed iron aluminide laser claddings

Abstract

FeAl-based materials demonstrate high mechanical stability at ambient and elevated temperatures at comparatively low overall ecological impact compared to classical wear-resistant materials. Therefore, laser metal deposited Fe₃Al-based claddings, alloyed with B, C, were prepared using a high-power diode laser at energy densities between 22 and 32 J/mm². With these parameters, precipitation strengthened claddings with a strong metallurgical bond to the substrate, increased hardness, containing about 30 at.% Al were achieved. Alloying with B results in the formation of very hard Fe₂B and FeB precipitates (14.1–25.0 GPa and 9.7–11.4 GPa respectively), leading to the highest macrohardness of 813 ± 9 HV10 for the 20 at.% B alloyed cladding. Alloying with C causes the formation of Fe₃AlC₀.₆ (7.6–7.9 GPa) and graphite (for higher C additions), with the 10 at.% C alloyed cladding showing a macrohardness of 500 ± 5 HV10. The combined 10 at.% B and 10 at.% C alloying results in a slightly higher hardness of 530 ± 34 HV10. Regardless of alloying, the Fe₃Al matrix itself provides a hardness of 4.4–5.2 GPa. In terms of wear resistance, the Fe30Al20B cladding demonstrates the lowest wear rate (0.0024 mm³/m) - outperforming other claddings like FeCrC or Stellite - but also Fe30Al10B and Fe30Al10B10C claddings offer high wear resistance (0.0133 mm³/m and 0.0173 mm³/m, respectively). These results highlight the better performance of the developed Fe₃Al-based claddings in comparison to currently used wear protection solutions – particularly those alloyed with boron – enabling wear protection without (high) amounts of Co, Cr and Ni.