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Mechanical alloying is a preferred approach for producing tungsten (W)–zirconium (Zr)-based alloys due to their vast difference in melting point and insufficient synergic solubility. This study comprises fabrication of nano-chromium oxide (Cr2O3)-dispersed W-Zr alloys through mechanically alloying for 20 h followed by conventional sintering in inert (argon) atmosphere at 1400 and 1500 °C with a 2-h holding time. Alloys A, B, and C are designated as per the following compositions: 98.5W-0.5Zr-1(Cr2O3), 97.5W-0.5Zr-2(Cr2O3), and 98W-1Zr-1(Cr2O3), respectively. The effects of the Zr and Cr2O3 addition to W and sintering temperature have been discussed in relation to mechanical characteristics. The phase evaluation and microstructural behavior of the powders and sintered samples has been studied using x-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy, respectively. The powder characterization after 20 h of milling through SEM has depicted a homogeneous mixture of Zr and Cr2O3 with W. Combined addition of Zr and Cr2O3 has resulted in a bimodal grain size distribution. The enhanced grain refinement coarse/fine particle count ratio due to mechanical alloying was observed in alloy A after 20 h, which was 1.57 compared to 2.6 in alloy C. The alloy A sintered at 1500 °C exhibited the highest densification (91%), hardness (13 GPa), wear resistance, and compression strength (1.37 GPa) due to better fraction of fine grains, solid solution, and dispersion strengthening compared to other alloys in both sintering temperatures. [ABSTRACT FROM AUTHOR]

W-Zr alloy has the advantages of high density, high strength and high reaction potential, which can not only exert the excellent penetration ability of tungsten-based alloy, but also provide additional damage by using the oxidation reaction of zirconium. W-Zr alloys have shown great application potential in reactive fragment, armor-piercing projectiles, and small caliber projectiles, and have attracted attention both domestically and internationally. The preparation methods, mechanical properties, and reaction characteristics of W-Zr alloy reactive structural materials were summarized in this paper, especially focusing on the penetration ability and energy release characteristics. On the basis, it was proposed that the future development of W-Zr alloys should focus on the regulation of combustion characteristics of W and the improvement of plasticity. Additionally, there is still a lack of systematic research on the synergistic mechanism between the microstructure, mechanical properties, dynamic fracture, and reaction energy release of W-Zr alloys, which requires further improvement through a combination of experimental research and simulation calculations.

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A W-Zr alloy doped with ceramic powder W _54.5 Zr _35-x Ni _6.7 Fe _3.3 Mo _0.5 (ZrO _2 ) _x was prepared by powder metallurgy. The effects of the ceramic content on the dynamic and static compressive mechanical behavior and energy release properties of the alloy were studied. The results showed that the addition of ceramics enhanced the energy release characteristics of the W-Zr alloy, and made the alloy break more thoroughly and the fragment cloud distribute evenly. The reaction delay time was shorter and the energy release reaction was more complete. However, the maximum temperature of the alloy reaction decreased. In addition, the addition of ceramics improves the mechanical properties of the material, and its compressive strength is much higher than that of traditional W-Zr alloys.(ZrO _2 )1 exhibited good mechanical behavior and energy release characteristics. The aftereffect damage performance was further verified using a ballistic gun experiment. Ballistic gun test results showed that (ZrO _2 ) 1 can penetrate A92124 aluminum targets with a thickness of 2 mm at a speed of 809.3 m s ^−1 and ignite post-target absorbent cotton, with both penetration and post-target damage capabilities.

Formation of the W 2 Zr intermetallic is the key reason for the low relative density and brittleness of W-Zr alloys. In this study, 65 W-Zr-Ti-Nb alloys with different Ti and Nb content were prepared by powder metallurgy. With the increase of Ti and Nb content, the proportion of the W 2 Zr in the alloy decreases, causing the densification of 65 W-Zr-Ti-Nb alloys. The thermodynamic calculation shows that the addition of both Ti and Nb results in a narrowing stabilized temperature range of W 2 Zr and an expanding stabilized temperature range of BCC-WTi x Nb y , respectively, ultimately causing the disappearance of the W 2 Zr and formation of the WTi x Nb y during non-equilibrium cooling. Both high ductility and strength can be achieved in the W-Zr-Ti-Nb alloys by assistance of the disappearance of the brittle W 2 Zr phase and the formation of the ductility WTi x Nb y. The first principle calculation indicates that the co-doping Ti and Nb results in a larger expansion on the spacing of the {110} close-packed plane and a smaller expansion or even shrinkage on the atomic spacing along the close-packed direction of the WTi x Nb y. Further, integrated crystal orbital Hamilton population (ICOHP) results proved that the bonding strength of W-Ti and W-Nb was weaker than that of W-W in WTi x Nb y. Both increased spacing of {110} plane and decreased interatomic bonding strength aid in reducing Peierls-Nabarro stress, promoting plastic deformation. This study provides a new method for improving mechanical properties by tailoring the phase constitution in W-Zr alloys through co-doping Ti and Nb. • W-Zr alloys with high plasticity and strength was achieved by tailoring the stability and deformability of W-rich phases. • The mechanism of Ti and Nb addition on the inhibition of the W 2 Zr in W-Zr alloy phase is revealed. • P-N stress reduction mechanism was revealed by analyzing lattice structure and interatomic bonding of W-rich phases. [ABSTRACT FROM AUTHOR]

In this paper, W-33.3 at% Zr super-saturated solid solution powder was prepared by mechanical alloying, and its formation mechanism and thermal stability were systematically studied. After 30 h of milling, 33.3 at% of Zr was completely dissolved in W, and a super-saturated solid solution with BCC structure was formed. When the milling duration was increased to 50 h, the single BCC phase was transformed into a dual-phase mixture with a super-saturated solid solution and an amorphous phase. Thermodynamic calculations based on Miedema theoretical model suggested that the W-33.3 at% Zr binary system tended to form solid solution first and then transform into amorphous. Furthermore, high resolution transmission electron microscopy observation revealed that grain refinement, lattice distortion and dislocation may play an important role in the process of solid solution expansion and amorphization. Finally, thermal stability tests suggested that the prepared super-saturated solid solution powder has shown good stability at 800 ℃ for 2 h, which provides more possibilities for the application of W-Zr metastable alloy powders. [Display omitted] • W-33.3 at% Zr super-saturated solid solution was prepared by mechanical alloying firstly. • W-Zr super-saturated solid solution powder is completely stable after holding at 800 ℃ for 2 h. • Phase evolution of W-Zr binary system was studied by thermodynamic calculation. [ABSTRACT FROM AUTHOR]