Résumé: Several methods were used to obtain the proper chemical composition and to determine the useful heat treatment to study the possible improvement of creep behaviour by fine precipitates of [gamma] phase (disordered and ductile) in Ni3Al alloy (ordered [gamma]' phase), which is an inverted structure with respect to that of superalloys.In the present work, compression creep tests were performed on the Ni78Al11Si11 alloy (in at.%) at temperatures and stresses near that of the flow stress peak observed at about 550 [deg]C. The stress exponent and activation energy of creep were determined. First observations of the microscopic creep behaviour were made after a low strain by transmission electron microscopy.

Langue: Anglais