Abd Al- khalaq Fawzy Hamood
Abstract
High power pulsed Neodymium doped Yttrium Aluminum Garnet- (Nd– YAG)- laser with 1J power was used to fuse coatings containing a mixture of FeAlO and Al. This mixture produced ...
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High power pulsed Neodymium doped Yttrium Aluminum Garnet- (Nd– YAG)- laser with 1J power was used to fuse coatings containing a mixture of FeAlO and Al. This mixture produced by aluminizing pack cementation treatment and thermal spray of low alloy steel, That is for Studying the mechanical , surface and metallurgical properties for each coating system , and to make a comparison before and after irradiation , and also the specified properties including the coating thickness . Aluminum Coated samples were made by two advanced techniques pack cementation and thermal spray methods in order to compare the resulted coating layer properties before and after irradiation, and also to determine the technique role from one hand ,also fusing effect and thermal residual stresses role which resulted from irradiation in the variation of studied properties on the other. Results showed that pack cementation coating layer has roughness, Micro hardness and wear resistance higher than thermal spray coating layer. Irradiation results was showed an improvement in studied properties, this was attributed to the fusing, thermal residual stresses and laser rays role in refining the grains which are in conjunction with finer microstructure . After irradiation a formation of a hard phase (martensite) was recorded, this was attributed to the sufficient percentage of carbon (0.4%) in the selected alloy, this was enshured by microstructure images taken by optical microscopy. X-ray diffraction showed, for laser surface irradiated coating layers, presence of the phase due to interaction between the base metal constituents. A modification of coating phases composition could be concluded for both coating techniques. Also the two techniques illustrate a formation of coating layer with a different thickness.