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( Ti 0.705 Fe 0.295 ) 100 − x Sn x (x=0 and 3.85) ultrafine eutectics were prepared by slow cooling from the melt through cold crucible casting. The addition of 3.85 at. % Sn to the binary Ti–Fe eutectic decreases the strength slightly but considerably improves the plastic deformability under uniaxial compressive loading from εf=2.1% to 9.6% strain to failure. The change in the morphology of the eutectic and the distribution of the FeTi phase are suggested as origin of the improvement of the mechanical properties.

Zr 62−x Ti x Cu 20 Ni 8 Al 10  (3⩽x⩽5) amorphous alloys crystallize via precipitation of icosahedral quasicrystals in the primary crystallization step, leading to nano-sized quasicrystals embedded in an amorphous matrix. Ti is the decisive component favoring the precipitation of quasicrystals. The mechanical properties of the crystallized alloys with different amounts of quasicrystalline phase were measured by compression and bending tests. If the volume fraction of quasicrystalline precipitates is below about 50%, the strength increases with an increasing amount of quasicrystalline precipitates, but the ductility does not decrease significantly in comparison with the amorphous counterpart. The fracture stress reaches 1835 MPa for 50 vol % of quasicrystals. Quasicrystalline precipitates of more than 60 vol % lead to reduction of ductility and strength. This shows a way of producing bulk quasicrystalline materials of high strength by crystallization of bulk amorphous alloys.

Articles you may be interested inEffects of quasicrystal formation on the crystallization of (Ti36.1Zr33.2Ni5.8Be24.9)100−xCux (x=5, 7, 9, 11, 13, 15, 17) metallic glasses J. Appl. Phys. 113, 033508 (2013); 10.1063/1.4775836Correlation between icosahedral short range order, glass forming ability, and thermal stability of Zr-Ti-Ni-Cu-(Be) glasses Appl. Phys. Lett. 91, 021907 (2007);

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Zr 73.5 Nb 9 Cu 7 Ni 1 Al 9.5 and Zr66.4Nb6.4Cu10.5Ni8.7Al8.0 composites of bcc β-Zr(Nb) dendrites embedded in a nanocrystalline matrix were prepared by slow cooling from melt. The increase of Nb content from 6.4 to 9 at. % slightly reduces the strength, but considerably improves the plastic elongation under uniaxial compressive loading from εp=0.6% to 14.8%. The interaction of strain with dendrites and the nanocrystalline matrix is suggested as origin of the improvement of the mechanical properties.

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