Deformation behavior during micro-pillar compression in an ordered phase strengthened single crystalline Ni–Cr–Mo micropillars at room temperature

Eliminating the interference of grain boundary, grain size and grain orientation, the effect of pure nanoscale ordered phases with Pt₂Mo-type structure on the micro-mechanical behavior of single crystalline Ni–Cr–Mo micropillar was investigated by micro-pillar compression at room temperature. The pattern of stress-strain curve on the deformed pillar containing ordered phases (LRO pillar) is quite different from that on the LRO free-pillar during compression. Increasing in yield strength induced by ordered phases for the pillar (360 MPa) is slight lower than that of the bulk sample (379 MPa) due to absence of the transition of ordered-disordered in the deformed LRO pillar. Nanostructural refinement induced by ordered phases is responsible for weak size effect sensitivity of the LRO pillar. The ordered phase also changes the preferred deformation mode from single (1(—)11)[011(—)] slip in the deformed LRO free-pillar into the dominant of double deformation twins combined with the stacking faults in the deformed LRO pillar. A remarkable disordering, as opposed to retaining of ordering in the deformed bulk sample, is found in the deformed LRO pillar. Dislocation with different mobile behaviors in the deformed LRO pillar due to starvation of dislocation may be responsible for the disordering.