Oxidation behavior and control method in laser solid forming of Rene 104 superalloy

To meet the increasing demand for complex-shaped components in aeronautical and naval industries, laser solid forming (LSF) technology has been used in the fabrication and field repair of superalloy components. In this study, fabricating Rene 104 superalloy parts by LSF was experimentally investigated. However, a severe oxidation problem was found in the LSF Rene 104 superalloy part even if the manufacturing area was protected by shielding gas, and the oxides would badly affect the mechanical performance of the LSF part. An optical microscope, a field emission scanning electron microscope, an energy dispersive x-ray spectrometer, and an x-ray diffractometer were used to analyze the oxidation phenomenon. The experimental result demonstrated that Al2O3 and Ti2O3 were the main components of oxides in the LSF sample and the oxidation problem deteriorated when the laser power increased. The reasons for the formation of oxides were analyzed according to the results from the temperature field simulation and oxygen concentration testing experiments. To solve the oxidation problem, a new method to control oxidation was proposed and a new protection device was designed in this study. The effect of the new method was verified by experiments, and the result showed that the oxygen concentration in the manufacturing area was effectively controlled using the new protection device and the oxidation of Rene 104 superalloy was prevented. It is believed that the new protection device can replace the glove box in the fabrication and field repair of large superalloy parts.