The Study On Microstructure And Property Of Blade And The Thermal Barrier Coatings

The heavy-duty gas turbine is widely used in industrial production and has greatpotential for development. The movable guide vanes of first stage bear themax-temperature rushing. It is one of the most difficult thing to develop the gas turbine.Improving the property of blade and thermal barrier coatings is crucial to increase theproductive efficiency of the heavy-duty gas turbine.In this paper, the effect of grit blast on the coating bond and deformation of base alloyis researched. The impact of thermal shock process on the organization and stress ofthermal barrier coatings has been analyzed. The thermal and stress field simulation ofpartial experiment in ANSYS and ABAQUS has been used. The microstructure on thermalshock samples is analyzed in stages.The results show that velocity, grit size, materials has a significant effect on stressdistribution of base alloy, can generate compressive stress under the base alloy. The valueof compressive stress is increased along with the increasing of gritblasting time andbecomes stable at last in the range of simulation. The value of maximum compressivestress and the deformation is also increased along with the increasing of the velocity, sizeand density of the sand. The base alloy after gritblasting is satisfied with the sprayedcondition. The location of maximum compressive stress concentrate to the center of basealloy. The last heat and cooling time of thermal shock test is selected five minutesaccording to the simulation. The microstructure morphology of as-sprayed coatings issatisfied with the test condition. After five hundred times, The constitude and theorganization are same with the as-sprayed. After one thousand times, The TGO has beengenerated. After two thousand times, The β phase has been generated. The size of β phaseincreased in proportion to the thermal shock times. The number of β phase decreased inproportion to the thermal shock times. After three thousand times, The thickness of TGO isincreased obviously and a little spinel oxide has appeared over the obvious alumina oxide.After four thousand times, The cracks have markedly increased in the borders of TBCs. After four thousand and five hundred times, The large cracks have extended over theboundary of TC and TGO. The thermal barrier coatings are partially spalling finally.