Actas de congresos
Characterization Of Laser Cladding Wc-co Composite Coatings [caracterização De Revestimentos Compósitos Wc-co Depositados Por Fusão A Laser]
Registro en:
58th Congresso Anual Da Abm (associacao Brasileira De Metalurgia E Materiais). , v. , n. , p. 3421 - 3430, 2003.
2-s2.0-1842576575
Autor
Pinto M.A.
Costa L.
Colaco R.
Vilar R.
Lerardi M.C.F.
Institución
Resumen
A number of works have shown that, if a proper selection of the operating parameters is made, laser cladding enables for the production of composite coatings with an homogeneous distribution of hard particles in a tough matrix free from defects, such as porosity or cracks. In the present work WC-Co composite coatings were produced by this technique. A powder mixture with 70%wt. of WC and 30%wt. of Co was used to produce the coating and an AISI 1045 steel was used as substrate. The microstructural characterization was made by optical microscopy, scanning electron microscopy (with EDS microprobe) and X-ray diffraction. Vickers microhardness tests were made in the cross section of the coatings. The microstructure of the coatings is essentially formed by a cobalt rich matrix with WC and Co3W3C carbide particles. Nevertheless, it was found that small local changes in the chemical composition results in different solidification paths that leads to dramatic modifications of the morphologies of the microstructural components. This results are discussed and analyzed on the basis of the C-Co-W ternary phase diagram.
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