图1   位错滑移型金属基体及其与纳米线匹配的二维点阵示意图,当位错(两根位错)滑移至界面时位错滑移基体输出应变的分布示意图

Fig.1   Two-dimension lattice schematic of the strain match between the nanowire and the dislocation slip matrix(a) matrix before dislocation slip(b) formed Burgers step (red line) after dislocation slip(c) atomic-scale high stress concentration (dotted circle) was generated when the dislocation moves to the interface between the nanowire and the matrix(d) schematic of the strain (ε) distribution when the dislocation slips to the interface, which shows the inelastic shear strain of matrix ({\epsilon }_{\mathrm{disl}}^{\mathrm{matrix}}) approaches 100% around dislocation and elastic strain of matrix ({\epsilon }_{\mathrm{el}}^{\mathrm{matrix}}) of about 0.2% away the dislocation

图2   点阵切变基体与纳米线匹配的二维点阵及应变分布示意图,基体发生应力诱发马氏体变形(马氏体和母相共存)过程中点阵切变基体输出应变的分布示意图

Fig.2   Two-dimension lattice schematic of the strain match between the nanowire and the lattice shear matrix(a) matrix before lattice shear(b) matrix after lattice shear(c) interface between the nanowire and the matrix after lattice shear, showing no atomic-scale high stress concentration(d) schematic of the strain distribution when the matrix experiences the stress induced martensitic transformation, which shows the elastic strain of matrix ({\epsilon }_{\mathrm{P}}^{\mathrm{matrix}}) of about 1% around parent and shear strain of matrix ({\epsilon }_{\mathrm{M}}^{\mathrm{matrix}}) approaches 7% around martensite. This 7% strain matches the elastic strain of the nanowire ({\mathrm{\epsilon }}_{\mathrm{el}}^{\mathrm{nanowire}}) of about 6% (red line)

图3   Nb纳米线/NiTi基体复合材料丝材及其微观组织^[12]

Fig.3   The macro and micro images of the nanowire Nb/NiTi composite^[12]
(a) a coil of composite wire with a diameter of 0.5 mm
(b) scanning TEM image of the cross section of composite wire (bright regions, cross sections of Nb nanowires; dark regions, NiTi matrix)
(c) TEM image of a longitudinal section of composite wire (NW indicates nanowire)
(d) macroscopic appearance of a bundle of freestanding Nb nanowires
(e, f) SEM images of the freestanding Nb nanowires

图4   Nb纳米线/NiTi记忆合金样品在原位拉伸过程中的高能同步辐射XRD谱以及Nb纳米线的晶格应变曲线^[12]

Fig.4   The high energy synchrotron XRD of the nanowire Nb/NiTi sample during tensile test and the evolution of the lattice strain with respect to the applied strain of Nb nanowire^[12](a) the diffraction peak of the Nb (220) plane perpendicular to the loading direction shifts obviously when the NiTi showing the stress induced martensitic transformation (SIMT—stress-induced martensitic transformation)(b) the diffraction peak of the Nb (220) plane perpendicular to the loading direction shifts slightly when the NiTi showing plastic deformation(c) evolution of the lattice strain with respect to the applied strain for Nb (220) planes

图5   Nb纳米线在位错滑移型金属基体中在应力诱发马氏体相变NiTi基体中的弹性应变极限,与文献报道的多种自由态纳米线的弹性应变极限的比较^[12]

Fig.5   Comparison of the elastic strain limits of Nb nanowires embedded in the matrix deforming by dislocation slip (1), Nb nanowires embedded in the matrix deforming by SIMT (2), and some freestanding nanowires (3)^[12]

图6   Nb纳米线/NiTi记忆合金复合材料(NICSMA)的拉伸应力-应变曲线、NICSMA性能占据三大类工程材料性能挑战区、NICSMA与其它金属材料屈服强度和弹性应变极限的比较、与其它材料屈服强度和弹性模量的比较^[12]

Fig.6   Tensile stress-strain curves of the nanowire in situ composite with shape memory alloy (NICSMA) composite (ε_e—elastic limit, σ_s—yield strength, E—elastic modulus) (a), comparison of strengths and elastic strains of ceramics, metals, polymers and our composite (marked by NICSMA) (b), comparison of the yield strengths and elastic strain limits of different materials (c), comparison of the yield strengths and Young's moduli of different materials (d)^[12]

图7   Nb纳米线/NiTi记忆合金样品的拉伸循环应力-应变曲线、样品在第一次加载过程中的同步辐射高能XRD谱、纳米线在第一次加卸载过程中的晶格应变曲线、纳米线在第二次加卸载过程中的晶格应变曲线^[13]

Fig.7   The cyclic tensile stress-strain curve of the nanowire in situ composite with shape memory alloy sample (a), evolution of the diffraction peaks for Nb (220), B2-NiTi (211) and B19'-NiTi (001) planes perpendicular to the loading direction during loading (b), evolution of the lattice strain with respect to the applied strain for Nb (220) plane perpendicular to the loading direction during the first cycle (c), evolution of the lattice strain with respect to the applied strain for Nb (220) plane perpendicular to the loading direction during the second cycle (d)^[13]

图8   Nb纳米线体积分数分别为10%和20%的NiTi记忆合金复合材料丝材的电子显微分析^[14]

Fig.8   TEM analyses of two NiTi shape memory alloy composites with 10% and 20% volume fraction Nb nanowire^[14]
(a, b) SAED patterns of longitudinal view of the two samples(c, d) TEM bright field images of the two samples corresponding to Figs.8a and b(e, f) HAADF images of the two sample(g, h) HRTEM image revealing the interfaces between a Nb nanowire and NiTi matrix

图9   在原位TEM拉伸过程中Nb纳米线的弹性变形行为^[15]

Fig.9   TEM study of lattice strain matching between Nb nanowires and the NiTi matrix^[15]
(a) bright feld image of a microbeam fabricated by means of focus ion beam milling(b) enlarged view of a Nb nanowire in the beam(c) HRTEM image of the region marked as c in Fig.9b(d) TEM image of the microbeam upon loading to about 3.23% strain(e) enlarged TEM image of the region marked as e in Fig.9d, showing the three martensite plates (marked as M1, M2 and M3) nucleated in the NiTi matrix(f~h) HRTEM images of the regions marked as f, g and h in Fig.9e(i~l) filtered HRTEM images of the regions marked as i in Fig.9c and as j~l in Figs.9f~h

图10   包含M1和M3马氏体板条区域的高分辨像及Nb纳米线中晶格应变的变化规律^[15]

Fig.10   HRTEM image of the region covering martensite plates M1 and M3. The interplanar spacing variation was calculated at an interval of seven (110)Nb planes (a) and distribution of the lattice strain as a function of distance from the start plane (b)^[15]

图11   Nb纳米带/NiTi基体复合材料丝的横截面和纵截面的STEM照片、垂直于加载方向的Nb (220)晶面的晶格应变与施加应变的关系曲线(插图为样品在室温下的拉伸应力-应变曲线)^[12]

Fig.11   STEM images of a cross-section (a) and a longitudinal-section (b) of a ribbion Nb/NiTi composite, evolution of the d-spacing strain with respect to the applied macroscopic strain for the Nb (220) plane perpendicular to the loading direction (Inset shows the stress-strain curve of the sample at room temperature) (c)^[12]

图12   Nb(110)晶面晶格应变与施加应变的关系曲线(插图是Nb纳米线/NiTi记忆合金复合材料拉伸应力-应变曲线)、在加载过程中B19′-NiTi(001)晶面的衍射强度与二维X射线衍射谱方位角的关系曲线、在8.7%循环前后马氏体态NiTi基体中孪晶形貌的比较、纳米线的弹性应变极限与以往文献报道的比较^[16]

Fig.12   Evolution of d-spacing strain with respect to applied strain for the Nb (110) plane perpendicular to the wire axial direction during tensile loading (Inset is the macroscopic stress-strain curve of the NICSMA composite) (a), evolution of X-ray diffraction intensity of B19′-NiTi <001> planes versus the azimuth angle during tensile loading (b), TEM micrographs of twin morphologies of the martensitic NiTi matrix before and after a tensile deformation cycle to 8.7% (c), comparison of the elastic strain limits of Nb nanowires embedded in the matrix deforming by dislocation slip (1), Nb nanowires embedded in the matrix deforming by detwinning (2), and some freestanding nanowires (3) (d)^[16]

图13   Nb纳米线/NiTi记忆合金复合材料在加卸载过程中Nb纳米线的晶格应变随外加应变变化曲线、复合材料在加载过程中的应力-应变曲线以及与商业化NiTi记忆合金的对比^[17]

Fig.13   The d-spacing strain with respect to applied macroscopic strain for the Nb (110) planes perpendicular to the loading direction in the NiTi-Nb composite (a), comparison of tensile stress-strain curves of the composite wire (red curve) and a commercial superelastic NiTi wire (yellow curve) (b)^[17]

图14   Nb纳米线/NiTi记忆合金复合材料及其与单体NiTi超弹性曲线的对比^[18]

Fig.14   The tensile cyclic stress-strain curves of the nanostructured Nb reinforced NiTi shape memory alloy composite wire (strain: 4% and 5%); the tensile cyclic stress-strain curve of a commercial superelastic NiTi shape memory alloy wire^[18]

图15   Ti₃Sn/TiNi复合材料微观组织结构^[19]

Fig.15   Typical microstructure of the TiNi-Ti₃Sn composite^[19]
(a) SEM backscattered electron images of the composite. The inset shows the Ti₃Sn (light)-TiNi (dark) lamellar structure at high magnification
(b) TEM bright-field image of the composite. The inset shows the button ingot of the composite
(c) HRTEM image of the interface between TiNi and Ti₃Sn
(d, e) display selected-area electron diffraction patterns of the Ti₃Sn and TiNi lamellae, respectively, shown in Fig.15b
(f) one-dimensional high-energy X-ray diffraction (HE-XRD) pattern of the composite. The inset contains its corresponding two-dimensional HE-XRD pattern

图16   Ti₃Sn/TiNi复合材料变形行为^[19]

Fig.16   Deformation behavior of the TiNi-Ti₃Sn composite^[19]
(a) the lattice strain evolutions of B19'-TiNi (022) and Ti₃Sn (201) planes perpendicular to the loading direction as a function of the applied macroscopic strain. The inset shows an enlarged view of the lattice strain curve of the TiNi in the initial stages of deformation
(b) the comparison of the elastic strains of Ti₃Sn achieved in our composite with different reinforcements (such as nanowires, laminates, and particles) embedded in conventional metal matrices, which are deformed by dislocation slip

图17   Ti₃Sn/TiNi复合材料的的室温压缩应力应变曲线、复合材料的力学性能和其它的高性能金属基复合材料对比^[19]

Fig.17   Room-temperature compressive stress-strain curve of the composite (a), comparison of the mechanical properties of our composite with those of other high-performance metal-based lamellar composites in which the soft component is a conventional metal (without the "J-curve" deformation attributes) rather than the biopolymer-like metal ("J-curve" deformation attributes) (b)^[19]

图18   复合材料丝双程驱动特性^[20]

Fig.18   Two-way actuated properties of the composite wire^[20]
(a) output strain-temperature curve of the composite without external load
(b) evolution of d-spacing strain with respect to temperature for the Nb (110) plane perpendicular to the wire axial direction

图19   Nb纳米线/NiTi复合材料在拉伸循环过程中的一维高能XRD谱、NiTi基体中Nb纳米线被保留弹性应变与拉伸应变的曲线、NiTi基体中Nb纳米线被保留拉伸和压缩弹性应变与文献报道的基材表面薄膜被保留拉伸和压缩弹性应变的比较^[16]

Fig.19   Evolution of high-energy X-ray diffraction peaks for Nb (110) and B19′-NiTi (001) planes through the multiple-step tensile cycles (a), evolution of d-spacing strain with respect to applied strain for the Nb (110) plane perpendicular to the wire axial direction during the multiple-step tensile cycles (b), comparison of the retained tensile and compressive elastic strains of large quantity Nb nanowires in the composite without external load and those of the reported thin films on substrates and embedded nanoinclusions in films (c)^[16]

图20   不同应变状态的10 nm Pt和5 nm Pt纳米膜的氧还原反应(ORR)线性伏安扫描(LSV)曲线对比^[28]

Fig.20   Polarization curves of the oxygen reduction reaction (ORR) of 10 and 5 nm Pt nanofilm under different strain states at a scan rate of 0.3 V/s. The data of 10 nm Pt nanofilm are shown with standard deviation^[28]