Strengthening of an L1₂-ordered g'-intermetallic by disordered g-precipitates

The effects of disordered g-precipitates on the critical resolved shear stress of an L1₂-long-range ordered g'-phase has been investigated along three lines:

1. computer simulations of the glide of dislocations in such a material,
2. measuring of the critical resolved shear stress of Ni₆₉Co₉Al₁₈Ti₄, measuring the g-particle dispersion by transmission electron microscopy, observing the relevant dislocation processes in this material,
3. representing all results by analytical formulae.

The results obtained by 1) and 2) are in good argument. In describing them by analytical formulae, special attention has to be paid to the choice of the dislocation line tension.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft

Beteiligte Wissenschaftler:

Dr. D. Baither, Dr. V. Mohles, Prof. Dr. E. Nembach, Dipl.-Phys. T. Pretorius, Dr. D. Rönnpagel (Institut für Metallphysik und Nukleare Festkörperphysik, TU Braunschweig, bis Frühjahr 2000)

Veröffentlichungen:

Pretorius, T., E. Nembach: Strengthening of an L1₂-ordered g'-intermetallic by disordered g-particles, Part 1: Computer simulations, Acta Mater., in press

Pretorius, T., D. Baither, E. Nembach: Strengthening of an L1₂-ordered g'-intermetallic by disordered g-particles, Part 2: Measurements of the CRSS and TEM observations of disloction processes in Ni₆₉Co₉Al₁₈Ti₄, Acta Mater., in press

Pretorius, T., D. Baither, W. Liu, D. Rönnpagel, E. Nembach: Particle hardening of an L1₂-ordered g'-(Ni,Co)₃(Al,Ti)-intermetallic - simulation calculations and bulk measurements, Proc. Int. Conf. Strength of Materials 12, 2000, Mat. Sci. Eng., in press