| Microstructural characteristics of the built up layer of cast alloy Inconel 713 by electrospark deposition |
| Paper ID : 1326-UFGNSM-FULL |
| Authors: |
|
Farshid Malek Ghaini *1, Mohsen Ghorbani Azar2, Mohammad Ebrahimnia3 1Jalal Al Ahmad Ave. 2Tarbiat Modares University,Tehran, Iran 3Tarbiat Modares University, Tehran, Iran |
| Abstract: |
| Buildup of precipitation hardened nickel base superalloys by electro spark deposition due to the low heat input of the process has many attractions. Characterization of the microstructure of the ESD built up layer of IN713LC over an as-cast base metal is accomplished in this work. The grain structure and solidification texture of the coating are investigated by optical and scanning electron microscopy. It is shown that the deposited layer is formed mainly through epitaxial nucleation and growth on the base metal structure while discontinuities acting as nucleation sites produce fine grains with independent orientations. An ESD machine which is designed and manufactured in Tarbiat Modares university was used for deposition on cast parts with 5 mm thickness. Same material was used as electrode (4 dia). Effect of process parameters like voltage, on time pulse and ferequency in form of inserted heat to the substrate, as well as cross section of samples were studied. It is shown that such independent grains can have a significant role in improving the integrity of the ESD built up layer, since they can act as crack arrest sites and make the coating more resistant to the propagation of liquation and solidification fissures. Moreover, it is found that nanosized γ′ precipitates (82nm) exist in the coating indicating the high tendency of γ′ for precipitation even in the extremely high cooling rates involved in the ESD process. Hardness measurements indicated a higher value for the built up layer which is attributable to the nanostructure of the coating. |
| Keywords: |
| Electrospark deposition, nickel based superalloys, nanosized γ′, IN713LC |
| Status : Paper Accepted (Poster Presentation) |
