X Ray Topography Study of Deformed Crystal-Quasicrystal Composites of Al Cu Fe Alloy

Abstract

Crystal-quasicrystal columnar composites (CQ composites) of Al Cu Fe alloy subject to tensile strain at room temperature were studied by the reflective X ray topography. In those composites singlecrystalline β phase occurred as the matrix and rods consisting of quasicrystalline ψ phase and crystalline λ phase as the reinforcement. X-ray topograms of plate like composite specimens were obtained using reflexes of singlecrystalline matrix. It has been found that at strains ε up to 0.33% in a linear range of stress strain σ(ε) relationship the topograms remain unchanged. Instead, at ε higher than 0.33% significant contract changes have been observed in some areas of topograms. It has been determined that at ε higher than 0.33% the components of misorientation angle of those areas increase with increasing strain. Methods of powder phase analysis, metallographic examinations by means of optical microscopy methods and X-ray diffraction topography methods were used.

The Fracture Morphology of Composites with Quasicrystalline Phase

“…The composites microstructure and spatial arrangement of reinforcement fibers are similar as in Ref. [8]. The plate-like samples for tensile tests were prepared from composite ingot using a spark erosion cutter, so that the tensile direction was parallel to the fibers direction.…”

“…In Ref. [8] presented that the crack growth take place in the matrix regions with small angle boundary and was preceded by the formation of the local strains at the matrix-reinforcement boundaries. However, the good quality of boundary between matrix and reinforcement made impossible to pull-out of fibers.…”