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Microstructure and Mechanical Properties of a Laser Coated TiB2/TiC/Al Layer on an Aluminium Alloy Substrate
D. Ravnikar, N.B. Dahotre and J. Grum

Laser coating was carried out on EN AW-6082-T651 aluminium alloy with a mixture of TiB2, TiC and Al powders using a diode pumped ytterbium fibre laser. The resulting coating was studied by means of a microstructure and microhardness analysis supported by microchemical analysis. The coating was adherent and free of cracks with average porosity lower then 2%. The average coating microhardness value was 160 ± 24 HV0.1, which represented a 66% higher microhardness value than that of the uncoated aluminium alloy (96.7 HV0.1). The average microhardness value in laser melt zone (LMZ) was 66.6 ± 7.6 HV0.1, whereas this value amounted to 71.6 ± 11.4 HV0.1 in the heat affected zone (HAZ). This was a significantly lower value than the microhardness value of the aluminium alloy prior to the application of coating. It was established that the microhardness value of the LMZ and HAZ may be improved through subsequent heat treatment.

Keywords: Fibre laser, laser coating, aluminium alloy, EN AW 6082-T651, ceramic components, TiC-TiB2, microstructure, microhardness, heat treatment

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