The preparation of boron nanosheets has very strict requirements of the preparation environment and substrate. In this work, the boron nanosheets were tried to prepare by the grinding method, using β-B alloy with stable chemical properties and large crystal plane spacing. Its morphology and chemical bonds of boron nanosheets were analyzed by scanning microscope (SEM), transmission microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The results show that the two-dimensional boron nanosheets can be prepared from β-B powder by the grinding method. There are very few B-O bonds in boron particles, and the B-B bonds are principally dominant. In addition to a few B-O bonds, including some B-B bonds change to B₆O bonds which are not completely oxidized, indicating that boron has certain oxidation resistance.

The goal of this research was to determine how the master alloys Al-5Ti-0.25C-0.25B and Al-5Ti-1B affected the mechanical properties and structural characteristics of the alloy Al-9.5Si-1.5Cu-0.8Mn-0.6Mg. Field emission scanning electron microscopy (FE-SEM) was used to probe the microscopic composition, and the mechanical properties were evaluated using tensile testing. The results showed that, by adding 0.5% Al-5Ti-0.25C-0.25B master alloy and 0.5% Al-5Ti-1B master alloy, the α-Al dendrites can be significantly refined. In the extrusion state, the ultimate tensile strength and elongation with 0.5% Al-5Ti-0.25C-0.25B master alloy reached 380 MPa and 11.2%, which were 5.5% and 22.4% higher than no refinement, respectively. The elongation of the samples with the Al-5Ti-1B alloy addition increased from 9% to 11.9%, which is attributed to the fact that more pronounced complete recrystallization occurred during the extrusion heat treatment.

Copper has high electrical and thermal conductivity, which is frequently employed in structural and functional materials. In this research, powder metallurgy was used to incorporate boron nanosheets into metal matrix composites to create boron dispersion-enhanced copper matrix composites. The neutron-absorption characteristics of composite materials were investigated, as well as the link between neutron-absorption cross-section and neutron energy. The results told us that the morphology of the second phase on the particle surface is closely related to the size of Cu-B particles, copper and boron correspond atomically to each other on the interface without dislocation or lattice distortion, forming a completely coherent interface, and that the neutron absorption cross-section decreases exponentially as neutron energy increases. In low-energy neutrons with energies less than 0.1 eV, the increase of boron content and ¹⁰B abundance in Cu-B alloy will enhance the neutron-absorption capacity of the alloy. Boron dispersion-strengthened copper matrix composites have good neutron-absorption capacity, and the microstructure and size of boron do not affect the neutron-absorption performance of composites with the same content of boron. The hardness of the B-dispersion-strengthened Cu matrix composite obtained by nanoindentation test is about 3.04 GPa. Copper matrix composites with boron dispersion reinforcement exhibit high hardness and neutron-absorption characteristics.

In this work, boron particles with β-rhombohedral structure were prepared in Cu-4B alloy. The morphology and growth mechanism of β-B and pentagonal twins were analyzed. Results show that boron crystals possessed an approximate octahedral structure which consisted of two planes belonging to {001} facet and a rhombohedron formed by {101} planes. The morphology of the boron crystal was determined by the position and size of {001} planes. During growth, parts of boron crystal formed twins to reduce surface energy. Five particular single crystals can shape a pentagonal twin. The morphological distinction between pentagonal twins mainly came from the difference in morphology of single crystal. When the {001} exposed planes were large and showed a hexagonal shape, the boron crystal often formed parallel groupings and polysynthetic twins to reduce surface energy.

Near-eutectic Al-Si alloys are widely used in automotive manufacturing due to their superior wear resistance and high temperature performance. Because of high Si content, the grain refinement of near-eutectic Al-Si alloy has been a problem for many years. In this study, the effect of deep cryogenic treatment (DCT) on the microstructure and mechanical properties of Al-12Si-4Cu-2Ni-Mg alloy with addition of Al-Ti-C-B master alloy was fully investigated. Results show that the average grain size of the alloy is greatly reduced from 0.92 mm to 0.50 mm, and the eutectic Si and Al₇Cu₄Ni precipitates are spheroidized and refined in Al-12Si-4Cu-2Ni-Mg after DCT for 24 h and aging treatment. Thereby these changes of microstructures result in a significant increment of about 22.5% in elongation and a slight enhancement of about 6.8% in tensile strength. Moreover, the refinement of microstructure also significantly improves the fatigue life of the alloy.