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The Ti/TiAl metal-intermetallic laminates were fabricated by hot-pressing starting from the elemental Ti and Al foils. The final microstructures of laminates consist of alternating layers of ductile Ti and brittle intermetallic. The relationships between mechanical properties and layer sequence of Ti/TiAl laminates have been studied by examining the effects of solid solubility of Al in Ti layer, the volume fraction of intermetallic layer and the interlayer spacing. In these three cases, the samples with the best performance are obtained and among them the optimal sample is confirm with fracture strength 752 MPa, K IC 48 MPa·m 1/2 . In particularly, a novel theoretical formula of strength calculation is proposed according to the mixing rule of composites. The theoretically calculated results agree well with the experimental results. [ABSTRACT FROM AUTHOR]

Ti/Ti-Al multilayered composites with different volume fractions of α-Ti layer were fabricated by hot press sintering. Microstructural observation indicates that the phase compositions in all the composites are α-Ti, Ti 3 Al, TiAl, TiAl 2 and TiAl 3 . The tensile strength and fracture toughness of Ti/Ti-Al multilayered composites are influenced by the volume fraction of α-Ti layer. The composite with 53 vol% Ti presents the highest tensile strength and suitable ductility at room temperature, and its fracture toughness can reach 47.6 MPa m , which is much higher than that of TiAl intermetallic alloy and Ti/Al 3 Ti composites. Fracture analysis reveals that a certain volume fraction of Ti layers can effectively prevent the crack propagation when the crack is extended to the interface, resulting in high tensile strength and acceptable ductility at the same time. The improvement of toughness is associated with crack deflection and crack bridging provided by the appropriate thickness of remaining α-Ti layer. [ABSTRACT FROM AUTHOR]

Abstract: In this study, Al–Ni–Ce–Fe–Cu alloy powders with composition of Al87Ni8.5Ce3Fe1Cu0.5 (at%) were atomized and then subjected to mechanical milling for different hours. The consolidation of the mechanical milled powders was performed by using spark plasma sintering followed by hot extrusion. Microstructure analysis and mechanical properties test were employed to the powders and the bulk samples, respectively. XRD patterns and DSC curves indicated that amorphous and nanocrystalline microstructure was obtained after milling for 170h. Room temperature compression test showed that the as-extruded bulk sample made from 170h milled Al–Ni–Ce–Fe–Cu powders had fracture strength of about 780MPa, however, without any visible fracture deformation. In addition, the ductility can be significantly optimized by introducing 20wt% pure Al powder. The strengthening mechanisms of the bulk samples were discussed. [Copyright &y& Elsevier]