B. Rottwinkel
I. Alfred
A. Pereira
C. Nölke
S. Kaierle
V. Wesling

Turbine blade tip single crystalline clad deposition with applied remelting passes for well oriented volume extension

International Congress on Applications of Lasers & Electro Optics (ICALEO)
16.-20. Oktober
San Diego
Type: Konferenzbeitrag
The objective of the work presented was to achieve a single crystalline (SX) clad on the tip of an SX turbine blade. It was assumed, that remelting could extend SX-height by re-solidifying the misoriented volume of its clad tracks. Thus remelting was used as a tool to ease clad epitaxy. All tests were performed with the SX Ni-based superalloys CMSX-4 or PWA 1426. To determine remelting parameters the following methodology was devised: An ideal energy input per unit was determined for each clad track shape by applying a variable laser power during the process, while travelling steadily. The energy value was defined using a combination of cross-sectional analyses and different laser parameters, thereby reducing the number of required tests to find effective track remelting parameters; This was then tested thoroughly on five differently-shaped CMSX-4 clad tracks to evaluate its validity. Thereafter, the remelting parameters from one chosen CMSX-4 track were applied to a similarly-shaped PWA 1426 track, resulting in a complete SX clad track. This SX track was used to form the SX deposition on top of the blade, which was also made of PWA 1426. The tests to evaluate the remelting methodology were carried out on the (010)/[100] or (010)/[001] crystalline orientations, which are equivalent to the orientations found on a turbine blade tip.