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In this work, graphene powder-reinforced Ti-Al metal-intermetallic laminated composite (GPEP-Ti/Al MIL composite) was designed and fabricated using the hot rolling and the vacuum hot-pressing sintering with the materials of graphene powder, titanium foil (TA1), and aluminum foil (1060 Al). The microstructure characterization of the composite was performed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffractometer (XRD), and the transmission electron microscopy (TEM). The results showed that single-phase Al3Ti was formed at the interface between Ti layer and Al layer. And the graphene powder and pure Al can be bonded well during the preparation process. In addition, the mechanical properties of the tensile, compressive, three-point bending, and fracture toughness tests indicated that the GPEP-Ti/Al MIL composite exhibits enhanced strength and superior plasticity. Ductile fracture predominates in Ti layer and Al layer, while the interface between them shows obvious brittle fracture. [ABSTRACT FROM AUTHOR]

In this paper, B2-FeAl based metal-intermetallic laminate (MIL) composites with and without NiTi shape memory alloy fibers were fabricated by two-step vacuum hot pressing combined with "multi-thin foils" stacking configuration. The microstructure of the composites were studied by scanning electron microscopy and electron backscattered diffraction. Compressive mechanical properties of the composites under quasi-static conditions and high strain rates are investigated via an Instron 5500R load frame and a Split Hopkinson Pressure Bar, respectively. Quasi-static compression stress–strain curves under the strain rate of 10–3/s at 20 °C and dynamic stress–strain curves under the strain rates of 1500/s and 2500/s at 0 °C, 20 °C and 80 °C were obtained, and fracture behavior of the composites were analyzed. The experimental results indicated that the strengths of the composites decreased unexpectedly under high strain rates compared to that under quasi-static condition whether or not NiTi fibers were introduced. Partial phase transition from austenite to ferrite occurred in metal layer during either quasi-static or dynamic compression process. During quasi-static compression, deformation was mainly concentrated in the metal layer. By contrast, metal layers and intermetallic layers exhibit similar deformation capacity during the dynamic loading process, thus, cracks easily appeared in intermetallic layers, causing the premature failure of the composites. Even so, B2-FeAl based MIL composites still possess the best dynamic mechanical properties in the MIL composites family to date. The strength of NiTi fiber reinforced composite is basically higher than that of the counterpart without NiTi fibers at each testing temperature, and fewer microcracks appeared in the intermetallic layer of the former. The reinforcing mechanism was discussed in details. [ABSTRACT FROM AUTHOR]

A novel specimen was designed to study the interface tensile behavior and fracture mechanism of the Ti/Al 3 Ti Metal-Intermetallic Laminate (MIL) composite under quasi-static and high strain rates. The experimental results indicated that the interface tensile strength of the Ti/Al 3 Ti MIL composite increases with increasing strain rate. The fracture mechanisms of the Ti/Al 3 Ti MIL composite are different under quasi-static (~0.001/s) and high strain (~300/s) rates. Generally, fracture only occurs in the interface under quasi-static tensile condition, while the fracture is also found in Al 3 Ti layer apart from the interface under high strain rate. The quasi-cleavage features are visible in the interface surface of Ti layer in both quasi-static and high strain rates. Moreover, large dimples are found in the fracture surface under high strain rate, and the tearing ridges are more than that under quasi-static strain rate. The brittle Al 3 Ti layers show an intergranular fracture behavior, along with minor transgranular fractures and secondary micro-crack formed in the grain boundary. [ABSTRACT FROM AUTHOR]

A novel Shape Memory Alloy NiTi fiber-reinforced metal-intermetallic–laminate (SMAFR-MIL) composite with a volume fraction of ~ 3.5% NiTi was fabricated using vacuum hot pressing method in this paper. The microstructure characterization of this laminate composite was performed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD), and the mechanical property of SMAFR-MIL composite was determined by compression test. In addition, damping capacity was measured using Dynamic Mechanical Analyzer (DMA) in a temperature range from 30 °C to 50 °C. The experimental results indicated that the average compressive strength and the strain to failure are ~ 1208 MPa and ~ 4.4% for loading perpendicular to the layers, and ~ 962 MPa and ~ 4.8% for loading parallel to the layers, respectively. The loss modulus of SMAFR-MIL composite is ~ 3.7 GPa, which is five times greater than that of Ti/Al 3 Ti laminate composite without NiTi fiber reinforcement, while the damping factor of SMAFR-MIL composite is ~ 4.5%. Both the mechanical and damping tests demonstrated that SMAFR-MIL composite is a new class of structural and functional composite with superior mechanical and damping properties. [ABSTRACT FROM AUTHOR]

Ti/Al 3 Ti metal-intermetallic laminate (MIL) composite is fabricated using Ti and Al foils through the vacuum sintering process. The fracture behavior of the MIL laminate composite under dynamic loading is investigated via modified Hopkinson bar loaded three-point bending fracture test. An experimental–numerical hybrid method is used to simulate the fracture behavior of MIL composite. In this method, the brittle damage model and plastic kinematic model are employed to represent the dynamic responses of the brittle intermetallic matrix Al 3 Ti and ductile reinforcement of Ti, respectively. As the boundary condition, displacement data obtained from dynamic three-point bending fracture test are imported into the finite element software package for simulation. Finite element model is validated through the comparison of the load–displacement curves from numerical simulation and the Hopkinson bar loaded three-point bending test. In addition, the dynamic damage evolution behaviors of the laminate composite, including crack deflection, delamination, plastic deformation, and brittle fracture are investigated using the post-process technique of finite element software package. The current study demonstrates that the MIL composite has excellent damage tolerance due to the multiple energy-absorbing mechanisms. [ABSTRACT FROM AUTHOR]

Continuous Al 2 O 3 ceramic fiber reinforced Ti/Al 3 Ti metal-intermetallic laminated (CCFR-MIL) composite was fabricated using a vacuum hot pressing (VHP) sintering method and followed by hot isostatic pressing (HIP). The microstructure characteristics of the interfaces between Ti and Al 3 Ti, as well as Al 2 O 3 fiber and Al 3 Ti intermetallic were analyzed by scanning electron microscopy (SEM). Elemental distribution in the interfacial reaction zones were quantitatively examined by energy-dispersive spectroscopy (EDS). The phases in the composite were identified by X-ray diffractometer (XRD). The mechanical properties of the CCFR-MIL composite were measured using compression and tensile tests under quasi-static strain rate. The experimental results indicated that the residual Al was found in Al 3 Ti intermetallic layer of CCFR-MIL composite. The interfacial reactions occurred during HIP and the reaction products were determined to be Al 2 Ti, TiSi 2 , TiO 2 and Al 2 SiO 5 phases. Compared to Ti/Al 3 Ti MIL composite without fiber reinforcement, both the strength and failure strain of CCFR-MIL composite under both compressive and tensile stress states increased due to the contribution of the continuous ceramic Al 2 O 3 fiber. [ABSTRACT FROM AUTHOR]

In this work, shape memory alloy NiTi fiber reinforced (SMAFR) Ti-Al laminated composites containing ∼41 vol%Ti and ∼2.5 vol%NiTi was fabricated via vacuum hot pressing method. In order to accurately determine the reaction products of the fabrication process, a new kind of laminated composites i.e. shape memory alloy NiTi plate-reinforced (SMAPR) Ti-Al laminated composites was successfully prepared using the fabrication process that is similar to SMAFR laminated composites. Results showed that Al 3 Ti and Al 3 Ni are formed during fabrication process, and residual Al existed in the intermetallic layer. In addition, the quasi-static tensile test indicates that the tensile property of SMAFR laminated composites is superior to that of Ti/Al 3 Ti composites. The fracture process of SMAFR laminated composite includes three basic stages: (I) delamination of interface of Ti/Al 3 Ti; (II) fracture of Al 3 Ti (and other products) and (III) fracture of NiTi fiber. Moreover, the novel SMAPR laminated composite possessed a good combination of high strength (compressive strength: 1105.4 MPa) and high plasticity (strain to failure: 5.1%), indicating that this kind of laminated composites is a new class of structural materials. [ABSTRACT FROM AUTHOR]

In this paper, a Ti6Al4V-Mg3AlZn laminate metal composite (TC4-AZ31 LMC) was successfully prepared by hot pressing sintering. The interfacial microstructure of this composite was investigated using scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD) and high resolution transmission electron microscopy (HR-TEM). The three-point bending (TPB) tests of TC4-AZ31 LMC were performed to determine the foil-foil interface bonding properties. Results show that the AZ31 matrix of the TC4-AZ31 LMC possesses a strong {10-10} <0001> sheet texture and the adjacent AZ31 foils are bonded well through the migration of grain boundaries across the original boundaries of the foils. A continuous interfacial reaction layer consisting of an intermetallics layer, a nanocrystalline-amorphous mixture layer and a bulk-precipitated particles region was formed around the TC4/AZ31 interface. The intermetallics layer bordering on TC4 reinforcement was identified as Al 192.40 Fe 46.22 phase. The nanocrystalline-amorphous mixture layer was composed of MgO nanocrystalline and Mg-O amorphous phase. The bulk-precipitated particles locating at the boundary of AZ31 matrix were determined as complex precipitates containing Al 6 Mn and Al 13 Fe 4 phases. Compared with the AZ31 alloy, the TC4-AZ31 LMC possessed a superior bending strength, which is attributed to the effective load transfer capability from the AZ31 matrix to high strength TC4 reinforcement through the well-bonded TC4/AZ31 interface. • The interfaces of TC4-AZ31 LMC were studied by EBSD and TEM systematically. • The extremely thin intermetallics and nanocrystalline-amorphous reaction layers were formed along the TC4/AZ31 interface. • The grains of AZ31/AZ31 interface were bonded together by grain boundaries migration. • The composite showed superior bending properties than AZ31 alloy. [ABSTRACT FROM AUTHOR]

In this work, continuous Mo fiber as a reinforcement was introduced into Ti/Al 3 Ti metal-intermetallic-laminated (MIL) composite via vacuum hot pressing (VHP). In order to avoid excessive consumption of Mo fibers reacting with Al, and also obtain an appropriate amount of Al 3 Ti, a Ti foil with the thickness of 0.1 mm as an expendable was inserted between the Al foil and Mo fibers. The microstructure characterization of the MIL composite was performed via X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the tensile mechanical properties were measured by employing an Instron-5500R load frame. Results indicated that after VHP, the inserted thin Ti foils were completely depleted and converted into the dominant phase Al 3 Ti, which existed in the intermetallic layer. Four Al–Mo intermetallic, Al 8 Mo 3 , Al 4 Mo, Al 5 Mo and Al 12 Mo were successively formed around Mo fiber. The sequence of these Al–Mo intermetallic can be well explained by the thermodynamics calculation combined with the kinetic factor. Tensile tests show that when the arrangement of the fibers is parallel to the tensile direction, the introduction of Mo fibers significantly improves the tensile strength and strain to failure of the composite fibers, which is obviously related to the excellent mechanical properties of the Mo fibers themselves and their good bonding with the matrix. • A novel Mo fiber reinforced Ti/Al 3 Ti metal intermetallic laminated (MIL) composite was prepared. • The Al 3 Ti was the dominant phase in the intermetallic layer. • Four Al–Mo intermetallic, Al 8 Mo 3 , Al 4 Mo, Al 5 Mo and Al 12 Mo were successively formed around Mo fiber. • The effect of the fiber was evaluated by calculating the energy consumption of material during the tensile process. [ABSTRACT FROM AUTHOR]