Product Code: ICAL06_1205

Qualification of Nd:YAG Laser Direct Metal Deposition Techniques for Repair of Nickel Superalloy Components
Authors:
A A Lugan, TWI Ltd; Cambridge Great Britain
C Rinaldi, CESI RICERCA SpA; Milano Italy
G B Melton, TWI Ltd; Cambridge Great Britain
Paul Hilton, TWI Ltd.; Great Abington, Cambridge Great Britain
Presented at ICALEO 2006

The high temperature operating components of power utility gas turbines are often made with gamma prime reinforced nickel based superalloys. As a result, there is a very high cost ascociated with the replacement of any parts damaged during service. The economic benefits to be gained by using repair procedures as opposed to replacement are considerable, with potential savings amounting to several million dollars per turbine. In this paper, the development of procedures for Nd:YAG laser direct metal deposition of nickel superalloys are presented. The paper describes the process by which high density and imperfection free deposition of the superalloy powder was achieved and goes on to describe production of a series of test specimens with geometries designed to qualify the quality of the deposition in terms of tensile, low cycle fatigue, and creep properties. The results of the tests show that the target of achieving high temperature mechanical properties in excess of 80% of the parent material properties, was achieved.