This work aims to improve the penetration ability of a 14.5 mm standard armor-piercing projectile into ceramic/armor steel (Al₂O₃/RHA) composite armor. To this end, ZrO₂ toughened Al₂O₃(ZTA) is prepared as the material for bullet tips, utilizing in situ solidification injection molding that is realized via ceramic dispersant hydrolytic degradation. The penetration power of ZTA ceramic composite projectile, compared with standard armor, against 15 mm armor steel (RHA) and 30 mm Al₂O₃/RHA composite armor, is studied by ballistics testing combined with numerical simulation. The Tate theory is optimized and then employed to calculate the penetration depth and bullet core’s residual mass when ZTA ceramic composite projectile penetrates into Al₂O₃/RHA composite armor. The results show that when penetrating RHA of 15 mm, the penetration area of ZTA ceramic composite projectile into RHA increases by 27.59% and the exit area by 42.93%. While the standard projectile fails to penetrate the 30 mm Al₂O₃/RHA composite armor, the ZTA ceramic composite armor-piercing projectile succeeds, with the mass loss reduced by 66.67% over the standard one. The ZTA ceramic composite bullet has a better performance than the standard bullet in penetrating RHA and Al₂O₃/RHA composite armors. The test results, simulation, and theoretical analysis are consistent. This study has practical values for engineering applications to design new ceramic composite bullets.

The penetration ability of a 5.8 mm standard projectile can be improved by inserting a ZrO₂ ceramic ball with high hardness, high temperature, and pressure resistance at its head. Thereby, a ceramic composite projectile can be formed. A depth of penetration (DOP) experiment and numerical simulation were conducted under the same condition to study the armor-piercing effectiveness of a standard projectile and ceramic composite projectile on 10 mm Rolled Homogeneous Armor (RHA) and ceramic/Kevlar composite armor, respectively. The results show that both the ceramic composite and standard projectiles penetrated the armor steel target at the same velocity (850 m/s). The perforated areas of the former (φ5 mm & φ2 mm) were 2.32 and 2.16 times larger, respectively, than those of the latter. The residual core masses of these two projectiles (φ5 mm & φ2 mm) were enhanced by 30.45% and 22.23%. Both projectiles penetrated the ceramic/Kevlar composite armor at the same velocity (750 m/s). Compared with the standard projectile, the residual core masses of the ceramic composite one (Ø5 mm & Ø2 mm) were enhanced by 12.4% and 3.6%, respectively. This paper also analyzes the penetration mechanism of the ceramic composite projectile on target plates by calculating its impact pressure. The results show that the ceramic composite projectile outperformed the standard projectile in penetration tests. The research results are instructive in promoting the application of the ZrO₂ ceramic composite in an armor-piercing projectile design.

To further enhance the hole-opening ability of the metal jet formed by the annular shaped charge on the armored steel target, a new annular shaped charge structure of a closed-cell W-shaped charge liner is designed based on a certain penetration depth. The impact of the length-diameter ratio of the charge, the inverted cone angle, and the cone angle of the liner on the opening diameter of the annular metal jet are studied through the orthogonal optimization of the annular shaped charge structures carried out by numerical simulation, which shows that the inverted cone angle and the cone angle of the liner are among the main factors that affect penetration depth and the opening diameter of the annular jet, respectively. According to this, an optimum annular charge structure considering both penetration depth and opening diameter is designed and tested by experiments. According to the results, the optimized annular jet records an opening diameter of 0.83 CD (Charge Diameter) when it penetrates the armored steel target with a thickness of 0.53 CD. The experimental results are consistent with the numerical simulation. The research results have certain practical engineering significance for guiding the design of the front-stage annular shaped charge structure of the multi-effect destructive warhead.

Titanium (Ti) and its nanoparticles are widely used in 3D printing due to a high corrosion resistance, biocompatibility, and lightweight potential. However, the atomic-scale mechanism of sintering densification and phase transition remains unclear, which limits the performance regulation of additively manufactured Ti components. In this work, molecular dynamics simulations were performed to study the sintering and phase-transition behavior of multi-sized Ti nanoparticles under 3D printing conditions. The melting point of 2 nm Ti nanoparticles decreases to about 1000 K, while that of 12 nm particles approaches the bulk value of 1941 K. Two distinct stages were observed during surface-energy-induced phase transition: initial lattice reconstruction at 800–1100 K, followed by complete melting above 1500 K. Smaller nanoparticles exhibited stronger pre-melting and faster atomic diffusion, which effectively filled interparticle pores and reduced the porosity. Increasing particle contact points shortens atomic diffusion paths, accelerates densification, and alleviates stress concentration. This study reveals the size-dependent sintering mechanism of Ti nanoparticles at the atomic level, providing theoretical guidance for the process optimization, microstructure control, and performance improvement of aerospace and biomedical titanium components fabricated by additive manufacturing.

Aiming at the reduction in penetration depth caused by the deformation and fracture of conventional 90W-Ni-Fe rod penetrators during ultra-high-velocity penetration, a lightweight tungsten-based ceramic alloy was fabricated in this study. Ballistics tests were conducted to verify the penetration performance of the novel lightweight alloy against concrete targets, and the existing theoretical penetration model was modified accordingly. The results indicate that, within the impact velocity range of 1400~1750 m/s, the penetration depth of both rod penetrators presents an initial increasing and subsequent decreasing trend, with an extreme value near 1625 m/s and a dimensionless penetration depth X_p/L close to 4. Compared with the traditional 90W-Ni-Fe alloy, the lightweight tungsten-based ceramic alloy penetrator achieves a mass reduction of 5.7%. In the impact velocity range from 1408.0 m/s to 1743.5 m/s, its penetration depth increases by 6.22%~10.58%, and the improvement becomes more significant with the increase in impact velocity. For the modified theoretical model, the predicted ultimate penetration depth of the lightweight alloy rod penetrator increases by 8.85%, while the average mass loss rate and average erosion rate decrease by 12.09% and 17.65%, respectively. The error between theoretical calculations and experimental data is within 5%.

This study proposes a novel synergistic design strategy to enhance the oxidation resistance of FeNiCuAl-based high-entropy alloys by integrating multi-element alloying (Cr-Co-Mn), trace Y modification, and laser-cladding-induced nanocrystallization. While the Base Alloy exhibited a mass gain of approximately 15 mg/cm² after oxidation at 900 °C for 120 h, the addition of Cr_2.5Co_2.5Mn_2.5 promoted the formation of a multilayered oxide scale (outer MnCr₂O₄/inner Al₂O₃), reducing the parabolic oxidation rate constant to 1.7 × 10⁻⁵ mg²·cm⁻⁴·s⁻¹. The originality of this work lies in the coupling of compositional and microstructural engineering; further addition of 0.5 at.% Y decreased this constant to 1.7 × 10⁻⁶ mg²·cm⁻⁴·s⁻¹—a three-order-of-magnitude reduction relative to the Base Alloy, while increasing the apparent oxidation activation energy to ~350 kJ/mol. After 100 thermal cycles at 1000 °C, the designed alloy showed a mass change of only 0.05 ± 0.02 mg/cm², with its critical load and interfacial fracture energy reaching 78 N and 14.8 J/m², respectively. Furthermore, the alloy retained a hardness of 310 HV, an elastic modulus of 135 GPa, and a tensile strength of 240 MPa at elevated temperature. These results demonstrate that the synergistic integration of chemical and structural optimization provides a new paradigm for designing low-cost, high-performance FeNiCuAl-based protective coatings.