High-performance B4C-YB4 composites fabricated with Y2O3 additive via hot-pressing sintering

Neodymium hexaboride (NdB6) is an important rare‐earth hexaboride material that has many structural and functional applications in advanced technologies. This paper presents the results on experimental studies of synthesis, densification, microstructural characterization, and mechanical properties of NdB6. Single‐phase NdB6 powder was obtained by the carbothermic reduction of Nd2O3 and B4C at optimized conditions and charge composition. Densification of NdB6 powders was carried out by pressureless sintering and hot pressing. The highest density of 93% theoretical density (TD) was obtained at 1800°C by hot pressing for 2 h in a vacuum, whereas 79% TD was obtained by pressureless sintering at 1900°C. However, 99.9% dense NdB6 was obtained by adding a sintering aid of 5 wt.% B4C using a hot‐pressing technique at 1800°C. Microstructural characterization revealed no significant grain growth during hot pressing at 1800°C, and a dominant transgranular mode of fracture was observed in fractography. Hardness values were measured as 23.8 and 28.8 GPa, respectively, by two different techniques micro‐ and nanohardness testers. Fracture toughness and elastic modulus of hot‐pressed NdB6 sample were measured as 3.04 MPa m1/2 and 484 GPa, respectively. The flexural strength of dense NdB6 was obtained as 156 MPa by three‐point bend test.

Section: Introductionmentioning

confidence: 99%

Studies on synthesis, densification, and characterization of neodymium hexaboride

Sonber,

Murthy,

Paul

et al. 2024

“…[2][3][4][5] Boron carbide (B 4 C) possesses desirable properties, such as low density, high hardness, and excellent wear resistance. [6][7][8] Titanium diboride (TiB 2 ) demonstrates exceptional mechanical properties, including high fracture toughness, relatively low density, excellent chemical stability, and a high modulus of elasticity. 9-18 B 4 C and TiB 2 are widely used in aerospace, wear components, cutting tools and lightweight protective materials because of their exceptional properties.…”

Section: Introductionmentioning

confidence: 99%

“…Boron carbide (B 4 C) possesses desirable properties, such as low density, high hardness, and excellent wear resistance 6–8 . Titanium diboride (TiB 2 ) demonstrates exceptional mechanical properties, including high fracture toughness, relatively low density, excellent chemical stability, and a high modulus of elasticity 9–18 .…”

Section: Introductionmentioning

confidence: 99%

Integrated preparation of B₄C–TiB₂ multilayer graded ceramics with high hardness and high toughness

Tan,

Zou,

Wang

et al. 2024

The enhancement in the comprehensive performance of hardness, toughness, and strength is significant for ceramic materials. In this study, the B4C–TiB2 multilayer graded ceramics were designed and integrally manufactured by spark plasma sintering method using B4C and TiB2 as raw materials. The B4C–TiB2 multilayer graded ceramics feature a transition from the top layer with high hardness to the bottom layer with high toughness, passing through an intermediate layer. The gradient change of this material is observed in both the hardness and fracture toughness, reaching values of 36.2–28.4 GPa and 2.2–6.2 MPa m.5. The compressive strength reaches up to 2960 MPa, whereas the bending strength gets to 677 MPa in the appropriate loading direction. The structure forms a gradient pattern with high hardness on the front side, high toughness on the back side, and overall low density and high strength. This study may facilitate the development of impact‐resistant performance of lightweight materials.

“…The fracture toughness, Vickers hardness, and flexural strength of B 4 C–LaB 6 18 and B 4 C–PrB 6 19 composites in the abovementioned two researches reached 4.92 MPa m 1/2 /4.40 MPa m 1/2 , 39.08 GPa/37.60 GPa, and 350 MPa/339 MPa, respectively. Wang et al 20 . fabricated B 4 C–YB 4 composites with 3 wt% Y 2 O 3 addition, of which the relative density, hardness, flexural strength, and fracture toughness reached 97.00%, 34.84 GPa, 422.67 MPa, and 4.92 MPa m 1/2 , respectively.…”

Section: Introductionmentioning

confidence: 99%

Microstructure evolution and performance of B₄C–NdB₆ composites fabricated by in situ hot pressing

Wang

Xing

et al. 2023

Self Cite

B4C–NdB6 composites were fabricated by in situ hot pressing at different temperatures (1950–2150°C) with B4C and Nd2O3 (2–4 wt%) as raw materials. The microstructure evolution of the composites with sintering temperature and Nd2O3 content was studied in detail, and the influence of pressure on the sintering of B4C with different contents of Nd2O3 was also investigated. The performance of the fabricated composites was researched and the toughening mechanism was discussed. The results indicate that Nd2O3 can react with B4C to form the thin‐sheet intermediate products (Nd(BO2)3, Nd2CO5) first, which then transform to band‐shaped NdB6. Pressure can reduce the distance of B4C and Nd2O3, accelerating the mass transfer and contributing to the formation of NdB6. NdB6 and intermediate products are first in agglomerate structure at 1950°C, and then the agglomerates are broken to form dispersive micron and submicron NdB6 at 2000°C by the synergistic function of pressure, diffusion at high temperature, and liquid phase sintering. NdB6 can enhance the densification owing to the bonding function. Excessive Nd2O3 content leads to residual pores, and excessive temperature (2150°C) results in the coarsening of phases. The coexistence of transgranular and intergranular fracture of NdB6 promote the fracture toughness.