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In this study, to meet the development and application requirements for high-strength and high-toughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere was designed and fabricated via diffusion bonding. The mechanisms of the microstructural evolution of the TaZrNb/TA15 interface were investigated via SEM, EBSD, EDS, and XRD. Interface mechanical property tests and in-situ tensile tests were conducted on the sphere-containing structure, and an equivalent tensile-strength model was established for the structure. The results revealed that the TA15 titanium alloy and joint had high density and no pores or cracks. The thickness of the planar joint was approximately 50–60 μm. The average tensile and shear strengths were 767 MPa and 608 MPa, respectively. The thickness of the spherical joint was approximately 60 μm. The Zr and Nb elements in the joint diffused uniformly and formed strong bonds with Ti without forming intermetallic compounds. The interface exhibited submicron grain refinement and a concave–convex interlocking structure. The tensile fracture surface primarily exhibited intergranular fracture combined with some transgranular fracture, which constituted a quasi-brittle fracture mode. The shear fracture surface exhibited brittle fracture with regular arrangements of furrows. Internal fracture occurred along the spherical interface, as revealed by advanced in-situ X-ray microcomputed tomography. The experimental results agreed well with the theoretical predictions, indicating that the high-strength interface contributes to the overall strength and toughness of the sphere-containing structure. [Display omitted] •High-strength mechanical properties of the interface of the TA15/TaZrNb MEA composite fabricated via diffusion bonding.•Investigation on the fracture mechanisms of the RVE embedded with a sphere by in-situ μCT tensile tests.•A tensile-strength equivalent model for the RVE embedded with a sphere is established.•The concave–convex interlocking structure at the interface plays a crucial role in resisting failure.

Two sol-gel fabrication processes were investigated to make silica spheres containing Ag nanoparticles: (1) a modified Stöber method for silica spheres below 1 μm size, and (2) a SiO2-film formation method on spheres of 3–;7 μm size. The spheres were designed to incorporate silver nanoparticles of high χ(3) in a spherical optical cavity structure for the resonance effect. For the incorporation, interaction between [Ag(NH3)2]+ ion and Si-OH was important. In the Stöber method, the size of the silica spheres was determined by a charge balance of plus and minus ions on the silica surface. In the film formation method, the capture of Ag complex ion on the silica surface depended on whether the surface was covered with OH groups or not. After doping [Ag(NH3)2]+ into silica particles or SiO2 films on the spheres, these ions w ere reduced by NaBH4 to form silver nanoparticles. From plasma absorption at around 420 nm wavelength and TEM photographs of nanometer-sized silver particles, their formation inside the spherical cavity structures was confirmed.