Fig.1 Design concept of SMA fiber-reinforced aluminum matrix composite [18]

Fig.2 Schematic figures concerning main factors for enhancing resistance to fatigue crack propagation: a compressive stress by shrinkages of TiNi; b stress-induced phase transformation of TiNi at crack-tip, and c high stiffness of TiNi above A f temperature [19]

Fig.3 Strengthening mechanism of composite by shape memory effect: a sintering; b shape memory heat treatment at 500 °C, followed by ice-quenching; c deformation processing (below A s); d heat treatment above A f [20]

Fig.4 Microstructure of TiNif/Al composite when TiNif was oxidized for different time durations: a 1 h; b 2 h; c 4 h; d 8 h [24]

Fig.5 a Bright-field TEM image of NiTif/Al interface with TiNif pre-oxidized for 1 h; b, c electron diffraction patterns of areas B to E in a close to Al and NiTif, respectively [24]

Fig.6 TEM images of NiTif/Al interface with TiNif pre-oxidized for 2 h a, 4 h b [24]

Fig.7 Composite lateral section microstructure of NiTif/6082Al composite fabricated by vacuum hot pressing [28]

Fig.8 Optical image of cross section of NiTif/6082Al composite prepared by vacuum hot pressing [29]

Fig.9 Prepreg setting for a vacuum hot pressing of NiTif/Al composite [35]

Fig.10 Effects of temperature and press pressure on bonding conditions between NiTif and Al sheets in TiNif/6061Al composite (the fiber diameter is 200 μm): a 773 K, 7 MPa; b 823 K, 7 MPa; c 873 K, 7 MPa; d 773 K, 14 MPa; e 823 K, 14 MPa; f 773 K, 54 MPa [35]

Fig.11 SEM images of interfacial microstructure of TiNif/6061Al composite with process temperatures of 773, 823 and 873 K [35]

Fig.12 Schematic diagram of ultrasonic consolidation process [44]

Fig.13 SEM micrograph of SMA-embedded specimen prepared by ultrasonic consolidation process [44]

Fig.14 a In UAM process, successive layers of metal tape are bonded together to create metallic composites with embedded materials. b Cross section of Al composite with embedded NiTi ribbon. [48]

Fig.15 TEM bright-field image showing multilayers formed at interface of NiTi/6061Al composite [52]

Fig.16 Mg-O thin layer 20 nm in thickness between Al3Ti and Al9FeNi layers [52]

Fig.17 SEM backscatter electron images of NiTip/2124Al composite sintered at 500 °C for 90 min: a 10 vol% NiTip; b 20 vol% NiTip; c detailed interfacial microstructure [59]

Fig.18 SEM backscatter electron images of NiTip/2124Al composite sintered at 500 °C for 15 min: a 10 vol% NiTip; b 20 vol% NiTip [60]

Fig.19 SEM images showing uniformly distributed NiTip in FSP composites a-c and of annealed composites d-f [62]

Fig.20 Schematic diagram of preparing bulk NiTip/6061Al composites by FSP (unit: mm) [63]

Fig.21 SEM images showing uniform distributions of NiTip in large a and small b NiTip reinforced 6061Al composite, backscattered electron (BSE) image and EDS line scan showing no interfacial reaction c and TEM image showing no interfacial reaction d [63]

Fig.22 Microstructure of NiTip/6061Al composite after T6 heat treatment showing no interfacial reaction: a SEM image; b TEM image; c HRTEM image [63]

Fig.23 Basic mechanism of bonding by spark discharge. Hatched areas are heated zones by spark discharge [69]

Fig.24 a SEM micrograph of NiTif/AZ31 composite fabricated by PCHP process; b SEM micrograph showing the white arrows show insufficient reacted areas between fiber and matrix (indicated by white arrows) [69]

Fig.25 SEM micrographs of TiNif/Mg composite: a cross section of TiNi, arrow denotes pressure direction of top punch, b magnified interfacial zone [71]

Fig.26 Microstructures of Mg/NiTi composites a Sample A (optical micrograph); b Sample C (SEM) [72]

Fig.27 Microstructures of NiTip/Mg parallel to swaging direction: a spherical TiNip and elongated Mg grains; b recrystallized grains in elongated Mg grains [73]

Fig.28 Schematic illustration of sheath-rolling process [74]

Fig.29 Optical micrographs acquired using polarized light showing CuAlNi particles embedded in different matrices: a pure In; b In-10 wt% Sn; c In-49.1 wt% Sn (eutectic) [77]

Fig.30 Comparison between NiTi/6082Al composites and 6082Al-T6 control, 25-120 °C unconstrained heating process results [29]

Fig.31 DSC heating curves showing effect of prestrain on phase transformation of TiNif embedded in Al matrix. [40]

Fig.32 DSC curves of as-received NiTip a and FSP NiTip/6061Al composite b [63]

Fig.33 Comparison of specific damping capacity for various materials [61]

Fig.34 Stress-strain curves measured at 363 K of unreinforced Al and NiTif/Al with 4.0 % prestrain and without prestrain, NiTif fraction of 4.0 and 9.0 vol% [18]

Fig.35 Correlation of crack length (a) versus cyclic number (N) a, crack propagation rate (da/dN) versus apparent stress intensity factor range (ΔK) b in NiTif/Al specimen (3 vol% NiTif, without prestrain) before and after the increase of temperature from room temperature (R.T.) to 90 °C (>A f) [19]

Fig.36 Relationship between the crack growth rate and stress intensity factor ΔK at room temperature and 363 K (volume fractions of NiTif are 0.0, 3.2, 5.2 and 7.0%): a ROA = 0.0%; b ROA = 20% [38]

Fig.37 Wear volume of various samples [51]