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1370 |
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Industrial technology of laser assisted direct metal deposition |
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Igor Smurov* / Ecole Nationale d'ingénieurs de Saint-Etienne (ENISE), France Ludovic Thivillon / Ecole Nationale d'Ingénieurs de Saint-Etienne (ENISE), DIPI Laboratory, France Philippe Bertrand/ Ecole Nationale d'Ingénieurs de Saint-Etienne (ENISE), DIPI Laboratory, France |
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Laser assisted direct metal deposition (or simply DMD) belongs to the family of laser cladding. This is flexible and efficient method for elaboration of diverse coatings including functionally graded, multilayered, etc. By DMD with coaxial powder injection it is possible to mix different powder producing coating with desired content ?in situ?, to create engineered internal structure. The coatings are characterized by excellent adhesion (metallurgical contact), low porosity and variable thickness up to several millimeters and even centimeters. Functionally graded coatings with advanced tribological properties were produced and examined on tribological reciprocating machine. The coating Stellite/CuSn/nanoWC/Co with solid lubricant matrix reinforced by both internal structure (Stellite lines) and dispersed ceramic phase have shown the best performance with stable dry friction coefficient 0.12. It is shown that the radiation mode is one of the critical parameters defining the coating?s microstructure (and thus, wear properties). Application of the pulsed-periodic mode provides better component remixing in comparison to the continuous wave mode. As follows from AFM analysis, nanostructure of some advanced powder materials, such as FeCu (produced by MBN, Italy) and NANOSTEELtm is partly preserved after laser cladding. Actually DMD technology is under development. The most important objective is to increase product quality, process stability and reproducibility along with the simultaneous decrease of risks, failures and defects both on processes and on end-products. The technology was up-graded to the industrial scale using TRUMPF 505 DMD machine with 5 kW CO2 laser. The targeted applications are related to petrol, chemical and plastics industries where wear resistance is improved by deposition of Stellite coating; in aeronautics DMD is used for Near Net Shape manufacturing from Inconel alloys. |