| Ni-based super-alloy has been used widely in the field of aerospace and gas turbines industry due to its higher temperature strength, plasticity, structure stability and nicer oxidation resistance and corrosion resistance. Studies on the surface modification and repairing of Ni-base super-alloy and its component parts have been paid much attention both at home and abroad because of its expensive cost and severe work environment. At present work, the experiments of laser surface remelting of GH3044 alloy and laser cladding Co- based alloy coatings of GH4169 alloy were conducted by the continuous wave HGL-6000 CO2 multifunctional numerical control processing device, respectively. Microstructure and micro-hardness in the remelting layer, cladding layer and binding region were measured and analyzed by means of metallographic microscope, scanning electron microscopy and micro-hardness tester. The effect of laser processing parameters on the microstructure and micro-hardness of laser remelting layer and cladding layer, and the effect of rare earth Y2O3 on the Co-based alloy cladding coating were studied. And the results are as follows.(1) The laser remelting layer of GH3044 mainly consists of slender column dendrite. The precipitates occurred in the remelting layer after aging at 900℃in 100h, and the larger P/v is, the crystal particles are finer. The precipitates reduced and the grains got coarser after solution treatment at 1160℃in 1h.(2) The dilution rate of Co-based alloy cladding coating of GH4169 alloy increased with increasing laser specific energy (SE). The grains got coarser also.(3) The coarse microstructure in the overlapping zone was found for the samples with multi-track overlaps. Moreover, the dilution rate increased and the micro-hardness decreased for the overlapping coatings.(4) The micro-hardness of the Co-based alloy cladding coating of GH4169 alloy increased by adding appropriate rare earth Y2O3, but decreased when 1.2%. Y2O3 was added. |
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