Interface strength in NiAl–Mo composites from 3-D X-ray microdiffraction

The depth-dependent strain gradients near buried interfaces in a model system of NiAl–Mo composite were nondestructively probed with 3-D X-ray microdiffraction. Coupled with micromechanical analysis, our study shows that the relaxation of the residual thermal strains in the NiAl–Mo composites results in the formation of a near-surface “slip zone” with large strain gradients in both the reinforcing Mo fibers and NiAl matrix. Based on these results an approach to calculate the fiber–matrix interface strength for composite materials is suggested.

Research highlights
► Strain gradients in NiAl–Mo composite were probed with 3D X-ray microdiffraction.
► Residual strains relaxation results in the formation of a near-surface slip zone.
► An approach to calculate the fiber–matrix interface strength is suggested.