Dislocation structure in precipitation-hardened Ir-based binary alloys

This paper examines the microstructure and the strength behavior up to 1800 degreesC of Ir-V, -Ti, -Nb, -Ta, -Hf, and -Zr alloys which formed fee and Lit L1(2) two-phase coherent structures. It is indicated that the precipitation-hardening effect depends on microstructure, resulting from differences in the lattice misfit. A maze structure such as in the Ir-Zr alloy was more effective for precipitation hardening than an orderly arrayed structure such as in the Ir-Nb alloy. The dislocation structure of deformed samples was investigated by TEM. The deformation mechanism of the alloys with different microstructures was discussed.