In this study, lanthanum hexaboride (LaB₆) particle-reinforced titanium matrix composites (PRTMCs, TC4/LaB₆) were successfully manufactured using the laser powder bed fusion (LPBF) process. Thereafter, the effect of the mass fraction of LaB₆ on the microstructure and the dynamic compressive properties was investigated. The results show that the addition of LaB₆ leads to significant grain refinement. Moreover, the general trend of grain size reveals a concave bend as the fraction increases from 0.2% to 1.0%. Furthermore, the texture intensity of prior β grains and α grains was found to be weakened in the composites. It was also observed that the TC4/LaB₆ have higher quasi-static and dynamic compressive strengths but lower fracture strain when compared with the as-built TC4. The sample with 0.5 wt.% LaB₆ was found to have the best strength–toughness synergy among the three groups of composites due to having the smallest grain size. Furthermore, the fracture mode of TC4/LaB₆ was found to change from the fracture under the combined action of brittle and ductility to the cleavage fracture. This study was able to provide a theoretical basis for an in-depth understanding of the compressive properties of additive manufacturing of PRTMCs under high-speed loading conditions.

As the critical parameter of hydraulic fracture evaluation, fracture density is significant for fracturing model optimization and production prediction. To compensate for the low response sensitivity of fracture density and the saturation of fracture evaluation in nonradioactive technology (NRT), we have developed a method based on modifying the neutron self-shielding effect to quantitatively calculate fracture density. The gamma counts of elements with content that did not change before and after fracturing are used to calculate the self-shielding correction factor. We establish the mathematical relationship between the corrected gamma counts of boron and fracture density to achieve a quantitative calculation of fracture density. Compared to NRT, the new method uses measured energy spectral information to eliminate the effect of neutron self-shielding on fracture density and improve calculation accuracy. Meanwhile, the scope or range of accurate fracture density estimation extends from the original 4% to more than 10%. Moreover, we further examine fracture response under different formations and borehole conditions using the Monte Carlo N-particle transport code. The salinity of formation water and borehole water has the most significant impact on fracture density calculation, shale content and porosity, lithology, and fluid type of formation; in contrast, borehole parameters are the least significant. Finally, in this paper, we illustrate the feasibility of the method through a continuous-depth numerical calculation.