Thermo-mechanical fatigue of polycrystalline, directionally solidified and single crystal nickel base superalloys repaired by laser beam welding

The low cycle thermo-mechanical fatigue of laser beam welded conventionally cast Inconel 738, directionally solidified Rene 80 and single crystal Rene N5 has been evaluated. Results have been compared to gas tungsten arc and baseline alloy conditions. Metallographic examination of laser beam welds and the associated heat affected zone were conducted by scanning electron microscopy and energy dispersive spectroscopy. The impact of laser beam welding on thermo-mechanical fatigue properties of Inconel 738, Rene 80 and Rene N5 has been evaluated and recommendations for improvements and areas of further research have been presented.