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In our research, boron was added into the Nb-added high strength low alloy (HSLA) H-section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H-section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test (V-notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

Nanodiamonds of different sizes doped with B and N impurities are studied by density functional theory. We find that the most stable sites for the B and N dopants are different. The substitutional B tends to stay in the middle region of a nanodiamond, while the energetically preferable site for N is on the surface of the nanodiamond. The chemical bonding and electronic properties of the B- and N-doped nanodiamonds are also discussed.

In this study, the relationship between the creep ductility and rupture life of 9Cr-1.5Mo steel with boron addition at 600°C was investigated by small punch (SP) creep test from the viewpoint of the modified Monkman-Grant relation. The amount of boron addition ranged from 0.0076wt% to 0.0196 wt%. The general concept of Monkman-Grant ductility for uniaxial creep was introduced and then particularly modified for the SP creep. The microstructure of the steel was observed to analyze the effect of boron addition on the creep ductility and rupture life. Based on the modified Monkman-Grant ductility for SP creep, it was found that the boron addition improved the creep ductility and rupture life of the 9Cr-1.5Mo steel. Also, the relationship between the minimum creep displacement rate and the amount of boron addition was analyzed.

In this study, we investigated stable structures for a transition metal atom–boron (CrB) wheel-like clusters and compared them with their corresponding 3D counterparts by means of density functional theory (DFT). In addition, hydrogen storage capability of the wheel-like system was investigated. All simulations were performed at the B3LYP/TZVP level of theory. We set out a complete route to the formation of CrB wheel-like clusters. Our results showed that, some of the clusters, investigated in this work (CrB_n; n = 4, 6, 7, 8), either prefer to be in a 3D geometry rather than 2D quasi-planar or planar geometry. However, hydrogen doping has an interesting effect on both 2D quasi-planar and 3D geometries of this system. Simply it transforms the 3D structure, first, into a 2D quasi-planar, then a planar geometry. Furthermore, our results show that H–cluster interaction is too high for reversible hydrogen storage for these clusters.

Boron nitride (BN) and Titanium nitrides (TiNs) have been successfully researched recently. In order to analyze the relationship among the Boron, Nitrogen and Titanium, the ternary compounds with an orthorhombic structure Immm- are studied. We further researched on the mechanical, electronic and optical properties of new Immm-B${}_x$Ti${}_{3-x}$N₂ ($x=1,2$). The structures of BTi₂N₂ and B₂TiN₂ are mechanically stable at 0, 50 and 100 GPa. The BTi₂N₂ has the higher cutting resistance and better ductility than the B₂TiN₂. The higher Young’s modulus of B₂TiN₂ indicates the B₂TiN₂ is stiffer than BTi₂N₂. The BTi₂N₂ is harder to compress in the $Y$ direction and the B₂TiN₂ is harder in $Z$ direction. Immm-BTi₂N₂ and B₂TiN₂ have good metallicity at 0 and 100 GPa. Immm-BTi₂N₂ has the higher dielectric function than B₂TiN₂ and the plasma frequency of B₂TiN₂ is bigger than that of BTi₂N₂. We hope our work will provide some help to the experimental work about the technology of the material.

Titanium alloys have poor wear performance, with severe adhesive wear and three-body abrasion being dominant mechanisms. To extend the use of titanium to applications demanding better wear properties, modifications can be made to the alloys. This can include the addition of hard particulates or interstitial strengthening, by increasing the oxygen or nitrogen content. The metal additive manufacturing process of selective laser melting (SLM) has been shown to enable manufacture of these modified titanium alloys in situ. In this study, small amounts of boron and titanium dioxide powders were added to Ti-6Al-4V (Ti64) and processed using SLM. To compare wear performance of these modified materials, reciprocating pin on plate tests in brine solution were performed. Increased oxygen content increased the hardness of the material, which reduced wear. The presence of boron increased wear in the short term but reduced the long-term wear rate. Incorporating of oxygen and boron has been shown to improve the saline solution wear properties of Ti64 against silicon nitride.

Employing a first-principles method in combination with the empirical criterions, we have investigated the site preference of boron (B) and its effect on the mechanical properties of the binary-phase TiAl–Ti₃Al alloy. It is found that B energetically prefers to occupy the Ti-rich octahedral interstitial site, because B is more favorable to bond with Ti in comparison with Al. The occupancy tendency of B in the TiAl–Ti₃Al alloy is the TiAl/Ti₃Al interface $>$ Ti₃Al $>$ TiAl, thus B tends to segregate into the binary-phase interface in the TiAl–Ti₃Al alloy. The charge density difference shows that B at the TiAl–Ti₃Al interface will form strong B–Ti bonds and weak B–Al bonds, leading to the significant increasing of the cleavage energy $({\gamma }_{\mathrm{\text{cl}}})$ and the unstable stacking fault energy $({\gamma }_{\mathrm{\text{us}}})$. This indicates that the presence of B will strengthen the TiAl/Ti₃Al interface, but block its mobility. Further, the ratio of ${\gamma }_{\mathrm{\text{cl}}}$/${\gamma }_{\mathrm{\text{us}}}$ of the B-doped system is 4.63%, 8.19% lower than that of the clean system. Based on the empirical criterions, B will have a negative effect on the ductility of the TiAl–Ti₃Al alloy.