Dresden 2003 – wissenschaftliches Programm
M 21.3: Vortrag
Dienstag, 25. März 2003, 12:15–12:30, IFW B
Low cycle fatigue of NiAl alloys: effect on the Ni3Al precipitates — •Peter Drechsler and Ferdinand Haider — Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstraße 1, 86150 Augsburg
The cyclic behavior of the stress response of polycrystalline Ni12.at%Al under lcf loading at frequencies from 0.025 Hz to 5 Hz or mean plastic strain velocities, 1 · 10−3 1/s < εpl < 3 · 10−1 1/s, and at temperatures between rt and 500∘C shows after the initial cyclic hardening caused by the formation of persistent slip bands further cyclic hardening or saturation and cyclic softening.
The samples were aged for 24 h at 600∘C and subsequently water squenched. The mean radius of the Ni3Al precipitates is about 5 to 6 nm.
Cyclic hardening occurs in a region above ca. 350∘C and below 3 to 4 Hz. tem investigation revealed few precipitate free bands. The particles are slightly sheared.
In the softening region precipitate free bands predominate. In the bands precipiates could not be proved by means of transmission elektron microscopy.
The mean particle size increases with temperature.