Materials
·
2025
·Vol. 18
·期 9
·2007
·
IF 3.2
Bo Xiao,Xia Zhang,Yongzhao Hou,Fagang Wang,Guangwu Wen
SiC-W2B5/C composites were prepared through a novel and simple processing route (reaction hot-pressing). The density of composites increased from 96.1% to 99.2% with the increase in SiC content from 5 to 30 vol%, leading to significant improvements in mechanical properties such as flexural strength, fracture toughness, and Vickers hardness, which for the highest W15S30 composite were measured at 292.3 MPa, 6.12 MPa·m1/2, and 3.32 GPa, respectively. The fracture morphology exhibited a mixed fracture mode of transgranular and intergranular, along with a pull-out phenomenon, indicating a well-combined interface. The sintering process involved Si powder acting as a liquid-phase sintering agent, reacting with B4C to increase the B concentration and promote the generation of W2B5, as well as reacting with the carbon phase to generate a transition phase of Si-B-C. The presence of this transition phase enhanced the interface bonding strength and catalyzed the graphitization process. As the SiC content increased, the promotion effect became more pronounced, with the degree of graphitization increasing from 59.2% to 66.2%.
研究领域:
材料科学
·
陶瓷材料
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 101
·期 8
·3617-3626
·
IF 2.956
Deng Pan,Shufeng Li,Xin Zhang,Bo Pan,Shengyin Zhou,Yabo Fu,Katsuyoshi Kondoh
Strip-shaped W 2 B 5 reinforced B 4 C ceramic composites were prepared via in situ reaction of boron(B)-graphite(Gr)-WC system by powder metallurgy (P/M). In order to study the effect of the graphite content on the properties of the as-fabricated ceramic composites, the powder mixture of B-Gr-WC with various amounts of Gr powder were blended and consolidated by spark plasma sintering (SPS). The sintering parameters were shown as following: sintering pressure was set as 30 MPa; The three-step sintering temperature was 1100-1550-1700°C and the duration time was set as 5-5-6 minutes, respectively. In situ formed strip-shaped W 2 B 5 particles were dispersed homogeneously in B 4 C matrix, which resulted in a remarkable improvement on the fracture toughness and mechanical properties. Appropriate 5vol% residual Gr in the composite shows positive effect on the mechanical properties which achieved an optimal counter-balance of fracture toughness and hardness, the relative density was 99.8%, the Vickers hardness can reach 30.2 GPa, and the fracture toughness was 11.9 MPa·m 1/2 when the sintering temperature was set at 1700°C.
研究领域:
材料科学
·
陶瓷工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Xiao-Hui Yang,Guo-Hua Zhang
The preparation of dense single-phase boride ceramics has always been a challenge. In this paper, single-phase W 2 B 5 ceramic with excellent performance was successfully prepared using W 2 B 5 powder and SPS-HF technology. Under the sintering condition of 1800 °C and 50 MPa, a nearly dense W 2 B 5 ceramic material with excellent mechanical properties was obtained. The relative density of the as-sintered W 2 B 5 ceramic achieved 96.72 % without any sintering additive. Additionally, the Vickers hardness , fracture toughness as well as bending strength were 30 GPa (9.8 N), 5.39 MPa·m 1/2 and 522.7 MPa, respectively. The outstanding hardness and bending strength of W 2 B 5 ceramic could be attributed to its monophase W 2 B 5 structure and high densification degree. The primary fracture mode of W 2 B 5 ceramic was transgranular fracture , and the toughening mechanisms included crack deflection, crack bridging, and crack branching.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2025
·
IF 4.6
Xiao-Hui Yang,Guo-Hua Zhang
Fully dense and fine-grained W 2 B 5 ceramics were successfully fabricated by spark plasma sintering at 1375 °C using metallic cobalt as additive. Co reacted with W 2 B 5 to form binary (CoB) and ternary phases (W 3 CoB 3 ) during sintering process. Experimental results showed that the relative density of W 2 B 5 ceramic increased from 96.7 % (for pure W 2 B 5 ceramic sintered at 1800 °C) to 99.0 % with 10 wt% Co addition and 99.5 % with 20 wt% Co addition (sintered at 1375 °C), respectively. Due to the lower sintering temperature, the grain size of W 2 B 5 in W 2 B 5 -10Co decreased from 5.3 ± 0.2 μm to 3.2 ± 0.1 μm relative to pure W 2 B 5 . However, in the case of 20 wt% Co addition, W 2 B 5 grains grew anisotropically, forming elongated strips with a length of 4.2 ± 0.3 μm and a width of 1.1 ± 0.2 μm. The W 2 B 5 -10Co composite exhibited superior mechanical properties with the Vickers hardness of 19.7 ± 0.3 GPa (30 Kg), fracture toughness of 8.7 ± 0.4 MPa·m 1/2 and flexural strength of 783.2 ± 22 MPa. Compared to pure W 2 B 5 ceramics, the hardness remained almost unchanged, while the fracture toughness and flexural strength were significantly improved by 61.8 % and 49.8 %, respectively. These improvements benefitted from the combination of high densification degree, fine-grained strengthening and in-situ CoB phase formation improving interfacial adhesion via semi-coherent interfaces. However, excessive addition of Co (20 wt%) induced stress concentration via brittle CoB coalescence, outweighing the densification benefit and drastically reducing hardness and flexural strength.
研究领域:
材料科学
·
陶瓷工程
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DOI
高影响因子
JOM
·
2025
·
IF 2.3
Yang Xiao-Hui,Wang Kai-Fei,Zhang Guo-Hua
A novel method for fabricating W 2 B 5− x -based ceramics was developed using in situ SPS of W and B 4 C mixed powders with various molar ratios (1.6:1, 1.8:1, and 2:1). The results revealed a primary reaction between W and B 4 C yielding W 2 B 5− x and graphite, alongside a minor residual B 4 C phase. All compositions achieved near-full densification, featuring a uniform microstructure composed of coarse B 4 C grains and fine graphite particles dispersed within the boride matrix. Quantitative phase analysis indicated that increasing the W/B 4 C molar ratio led to a progressive increase of the W 2 B 5− x phase and a slight increase of graphite but a marked decrease of the residual B 4 C. Mechanically, Vickers hardness declined from 15.63 GPa ± 0.40 GPa to 14.28 GPa ± 0.34 GPa (under a 30 kg load) as the W/B 4 C ratio increased, attributable to the diminished content of high-hardness B 4 C and the grain coarsening of the W 2 B 5− x . The flexural strength exhibited a similar downward trend, with a maximum value of 620.4 MPa ± 45.4 MPa achieved at a W/B 4 C ratio of 1.6. Remarkably, fracture toughness improved from 7.94 MPa·m 1/2 ± 0.04 MPa·m 1/2 to 9.21 MPa·m 1/2 ± 0.08 MPa·m 1/2 , primarily because of graphite-induced toughening mechanisms such as crack deflection, branching, and bridging.
研究领域:
材料科学
·
陶瓷
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）