Sana Chaabani joint PhD between Mondragon Unibertsitatea and Arts et Métiers ParisTech (ENSAM)

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Sana Chaabani joint PhD between Mondragon Unibertsitatea and Arts et Métiers ParisTech (ENSAM)

THESIS

Sana Chaabani joint PhD between Mondragon Unibertsitatea and Arts et Métiers ParisTech (ENSAM)

Title of the thesis: "Cryogenic machining of the aeronautic alloy: Inconel 718". Obtained the SOBRESALIENTE CUM LAUDE qualification.

2021·06·28

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  • Title of the thesis: "Cryogenic machining of the aeronautic alloy: Inconel 718".
  • Court:
    • President: Dr. Lorenzo Sevilla Hurtado (Universidad de Málaga)
    • Vocal: Dr. Yessine Ayed (Arts et Métiers ParisTech)
    • Vocal: Dr. Óscar Martín Llorente (Universidad de Valladolid)
    • Vocal: Dr. Pedro José Arrazola Arriola (Mondragon Unibertsitatea)
    • Vocal: Dr. Mohammed Nouari (Institut Supérieur d’Ingénierie de la Conception)
    • Vocal: Dr. Jose Carlos Outeiro (Arts et Métiers ParisTech)
    • Secretary: Dr. Aitor Madariaga Zabala (Mondragon Unibertsitatea)

Abstract

Nickel-based alloys are widely used in the manufacture of aerospace engine components due to their excellent high-temperature thermo-mechanical properties and good corrosion resistance. However, machining these materials poses a number of challenges, mainly because they maintain their properties at high temperatures. Additional difficulties result from their high chemical reactivity with most cutting tool materials and their low thermal conductivity, which leads to wear due to the high temperatures reached at the cutting edge. In this context, the use of cooling/lubrication systems are very relevant in order to improve productivity in machining.

Thus, this research work focuses on cryogenic machining, which consists of projecting liquid nitrogen (LN2) or liquid carbon dioxide (LCO2) into the cutting zone to reduce the temperature. The aim is to reduce some wear mechanisms and increase tool life. However, the application of this lubrication system machining Inconel 718 has to date shown limitations in terms of tool life and surface integrity of the machined part, as opposed to Ti64 titanium alloy. It is therefore considered of great interest to discern the mechanisms responsible for the poor machinability of Inconel 718 in cryogenic machining in order to propose a suitable process window. To this end, the dynamic behavior of Inconel 718 at cryogenic temperatures is characterized to determine the metallurgical alterations that may occur in the machined part. The surface integrity condition obtained is also analyzed and a study is made of the fatigue behavior of drilled specimens under cryogenic conditions.