A novel Ni2MnCuSnAl0.1 multi-principal element alloy coating to enhance the wear resistance and corrosion resistance of Mg-Li alloy

The evaporation and dilution of substrate are the key deficiencies that limit the performance of laser-cladded coatings on Mg-Li alloys (or Mg alloys). In order to overcome these drawbacks, in this work, a novel Ni2MnCuSnAl0.1 multi-principal element alloy (MPEA) coating and a multi-step ultrasonic assisted laser cladding technique were proposed. Dense metallurgical Ni2MnCuSnAl0.1 MPEA coatings were successfully synthesized on Mg-Li alloy. Typical gradient microstructure of low-diluted layer, diffusive layer and interfacial layer were obtained in the coating. The low-diluted layer was composed of BCC solid solution, Ni2MnAl and Ni2MnSn while the diffusive layer and interfacial layer showed an interactive microstructure of Mg-CuMg2 eutectic, Ni2MnAl, Li2MgSn/SnMg2 and Mg/Mg-Li substrate. The corrosion potential of Ni2MnCuSnAl0.1 MPEA coating (-108 mVSHE) was 1283 mVSHE higher than that of Mg-Li alloy (-1391 mVSHE), while the corrosion current density of the coating (5.85 x 10-7 A.cm- 2) was about three orders of magnitude lower than that of Mg-Li alloy (1.12 x 10-4 A.cm- 2). The micro-hardness gradually increased from the substrate to the coating, and the average microhardness of the coating was - 541.2 HV0.2, which is about 10 times higher than that of Mg-Li alloy (-57.8 HV0.2). The wear resistance of Mg-Li alloy was also improved approximately 10 times by cladding Ni2MnCuSnAl0.1 MPEA coating.

Automated summary

A novel Ni2MnCuSnAl0.1 multi-principal element alloy coating and a multi-step ultrasonic assisted laser cladding technique were proposed to overcome the deficiencies of evaporation and dilution of substrate in laser-cladded coatings on Mg-Li alloys. The synthesized Ni2MnCuSnAl0.1 MPEA coatings on Mg-Li alloy exhibited improved corrosion resistance, hardness, and wear resistance compared to the Mg-Li alloy.