Abstract
Ni superalloys are widely used for hot section components in jet engines because they are very resistant to corrosion and maintain reasonably high strength at elevated temperature. However, the repair cost of the parts is high, partly due to the complexities of process variable optimization and control in laser cladding. In particular, optimizing the process parameters by experiments is time-consuming and costly. The microstructure and properties of the metal deposit are significantly influenced by values temperature gradient G and solidification rate R at the weld pool solidification boundary. Optimized values can help to reduce defects and improve properties of laser deposits. Optimization is hindered by the fact that the clad melt pool is hot and small, making in situ measurement of such solidification conditions difficult. Numerical simulation of the laser deposition process is a possible alternative to experimental measurement to obtain values of clad solidification parameters. In this investigation, G and R values at the weld pool solidification boundary were obtained from a three dimensional numerical simulation of laser deposition process and melt pool. The primary dendrite arm spacing and cooling rate of the deposited material were then correlated to these solidification conditions.
Original language | English |
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Pages (from-to) | 1520-1529 |
Number of pages | 10 |
Journal | Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science |
Volume | 45 |
Issue number | 4 |
DOIs | |
State | Published - Aug 2014 |
Externally published | Yes |
Funding
The authors would like to thank Rolls-Royce Corporation for the funding support and providing laser cladding samples in this work. They also appreciate NSF-I/UCRC: Center for Integrative Materials Joining Science for Energy Applications. The authors express their thanks to J.S. Bader for helpful suggestions and interest in this project.