CERAMICS INTERNATIONAL
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2025
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IF 5.6
Xuanzhi Chen,Yehua Li,Youwu Liu,Pengjin Huang,Haidong Wu,Shanghua Wu,Xin Deng
Si 3 N 4 ceramics were sintered at 1850 °C and 2 MPa in a nitrogen atmosphere, using Gd 3 Si 2 C 2 -MgO as a sintering aid. The impact of Gd 3 Si 2 C 2 content and sintering dwell time at 1850 °C on the relative density, microstructure, and thermal conductivity of the Si 3 N 4 ceramics was investigated. The results indicate that under 4 h of sintering, increasing Gd 3 Si 2 C 2 content significantly enlarges Si 3 N 4 grain size while reducing microstructural uniformity; however, after 8 h, grain size refines and uniformity markedly improves. This phenomenon is mainly attributed to the increase in Gd 3 Si 2 C 2 content, which raises the number of β-Si 3 N 4 nucleation sites, thereby facilitating grain growth during short-term sintering; whereas during long-term sintering, the further enlarged grains generate a spatial hindrance effect, promoting the homogenization of the microstructure. Furthermore, under the same Gd 3 Si 2 C 2 content, extending the sintering time is beneficial to the growth of silicon nitride grains and the reduction of the glass phase, enhancing the continuity of Si 3 N 4 /Si 3 N 4 interfaces and thereby improving the thermal conductivity of Si 3 N 4 ceramics. The maximum thermal conductivity of 107.25 W·m −1 ·K −1 was achieved with a Gd 3 Si 2 C 2 content of 1 mol% and a sintering period of 8 h at 1850 °C.
研究领域:
材料科学
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陶瓷
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热性能
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
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2024
·
IF 2.2
Li Pengfei,Sui Yudong,Jiang Yehua,Zhou Mojin,Wang Zhijie
The effects of MgO addition on the microstructure and mechanical, frictional, and wear properties of zirconia-toughened alumina (ZTA) ceramics were investigated in this study using hot pressure sintering (HP). The addition of trace amounts of MgO led to the refinement of the ceramic grains and an increase in the ceramic density due to the pinning effect of MgO. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results revealed that an MgAl 2 O 4 phase was formed in the ceramics, which also contributed to the refinement of the ceramic grains. Moreover, the addition of MgO promoted the uniformity of the ceramic microstructure. Among the tested composites, the composite with 0.4 wt.% MgO exhibited the most favorable comprehensive properties, including a relative density of 99.61%, hardness of 18.29 GPa, and indentation fracture toughness of 9.15 MPa·m 1/2 , thereby offering the highest resistance to adhesive wear.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2021
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IF 3.871
Hairui Xing,Ping Hu,Jiayu Han,Shilei Li,Songwei Ge,Xingjiang Hua,Boliang Hu,Fan Yang,Kuaishe Wang,Pengfa Feng
Molybdenum metal have high brittleness and ductile-to-brittle transition temperature (DBTT) due to the existence of interstitial oxygen impurities, so it is of great scientific significance to strictly control and accurately analyze the oxygen content. In this work, the effects of oxygen on microstructure and evolution mechanism of body-centred-cubic metallic molybdenum are studied. The X-Ray diffraction (XRD), oxygen nitrogen analyzer, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and electron probe micro-analyzer (EPMA) are used to analyze the chemical composition, microstructure, oxygen existence and distribution form. The results demonstrate that Mo O specimens with up to 3300 ppm of oxygen content have single-phase body-centered cubic microstructure with no precipitates. When the oxygen content in molybdenum increases from 44 ppm to 2200– 3300 ppm, more oxygen exists in the pores between molybdenum grains, and the fracture mode changes from intergranular fracture to intergranular and transgranular mixed fracture. The microhardness increases with increase of oxygen content. These results provide new ideas for controlling the change trend of oxygen in molybdenum and regulating the properties of molybdenum.
研究领域:
材料科学
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金属学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Hao Jiang,Shuailing Ma,Xingbin Zhao,Hao Zhang,Kaiping Hu,Yanping Huang,Tian Cui
High-purity and well crystalline Cr 2 AlB 2 ceramics were fabricated from Cr and AlB 2 powders using a high pressure and high temperature (HPHT) method. The effects of sintering temperature, duration and pressure on the sintering process were systematically investigated using X-ray diffractometry. Optimal sintering conditions were identified as 1600 °C, 5 GPa, and 1 h. Scanning electron microscopy analysis revealed that the Cr 2 AlB 2 sample possesses an elongated and lamellar microstructure, with individual layers measuring a few hundred nanometers in thickness. Cr 2 AlB 2 samples exhibited a Vickers hardness of 9.9 GPa, with outstanding mechanical properties, including high fracture toughness and Young's modulus of 5.3 MPa m 1/2 and 379.1–434.5 GPa, respectively. Transmission electron microscopy analysis detected edge dislocations, wrinkle defects, lattice twist and distortion within the crystals, all contributing to the enhanced hardness and toughness. X-ray photoelectron spectroscopy analysis reaffirmed prior findings regarding the anisotropic chemical bonding in Cr 2 AlB 2 , characterized by strong intralayer bonds and weak interlayer interactions. The electron transfer and capture between layers are crucial for stabilizing the Cr-B layer substructure.
研究领域:
材料科学
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固体力学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2025
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IF 4.6
Fengshun Du,Bohua Duan,Dezhi Wang,Zhuangzhi Wu,Xinli Liu
Improving the poor plasticity and fracture toughness of molybdenum alloys is the key to expanding their industrial applications. In this experiment, a cerium partially stabilized zirconia (Ce-PSZ) reinforced molybdenum alloy with outstanding properties was obtained by combining the hydrothermal method and the powder metallurgy technology. This study investigated how varying Ce-PSZ content influences the microstructure and mechanical properties of Mo/Ce-PSZ alloys. The results show that with increasing Ce-PSZ addition, the relative density and hardness of the alloys gradually increase, while the tensile strength, plasticity, and fracture toughness exhibit a tendency to initially increase and subsequently decrease. When 1.5 wt% of Ce-PSZ is added, the Mo alloys achieve excellent overall mechanical properties, with an ultimate tensile strength of 528.5 MPa, elongation of 29.3 %, and fracture toughness of 38.5 MPa∙m 1/2 . These values are about 22.7 %, 22.5 %, and 83.3 % higher than those of pure molybdenum. The substantial enhancement in elongation and fracture toughness can be predominantly ascribed to the refinement of grains and the stress-induced Ce-PSZ phase transformation. This research provides a novel method for the preparation of molybdenum alloys with high fracture toughness and elongation.
研究领域:
材料科学
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冶金工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2023
·
IF 3.6
Xiao-Chun Deng,Xin Lan,Ya-Long Wang,Guo-Hua Zhang
Mo 2 C doped WC-10Co alloys were prepared via an in - situ synthesis method composed of steps of spray drying, roasting, carbothermal pre-reduction and carbonization-vacuum sintering. The effects of Mo 2 C content on the microstructure and mechanical properties of cemented carbides were studied in detail. The results showed that WC and Mo 2 C formed a complete solid solution by the current method. With the increase of Mo 2 C content from 0 wt% to 0.5 wt%, the effects of solution strengthening and fine grain strengthening were obvious, and the grain size was decreased from 0.72 ± 0.32 μm to 0.62 ± 0.27 μm, while the hardness was improved from 1316 ± 20 HV 30 to 1549 ± 14 HV 30 . However, the (W, Mo)C solid solution would deteriorate the fracture toughness of the alloys. With the further increase of Mo 2 C content to 9 wt%, the lattice distortion in the solid solution became more serious. Meanwhile, the dissolution of more Mo 2 C in the liquid Co further weakened the dissolution-precipitation process of the solid solution, thus inhibiting the growth of grains and increasing the hardness of the alloys. In addition, with the increase of Mo 2 C content, the dominant fracture mode of the alloy changed from transgranular fracture to intergranular fracture .
研究领域:
材料科学
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机械工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2018
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IF 3.057
Zhuang Lu,Limeng Liu,Guihong Geng,Alexander M. Laptev,Zhaoping Hou,Yujin Wang
TaC ceramics with 0.03–0.60 wt% of boron additions were prepared by hot pressing at 2100 °C for 1 h under a pressure of 40 MPa. Effects of boron content on densification, phase composition, microstructure, mechanical properties and oxidation resistance of the TaC ceramics were investigated. When the boron content was 0.12 wt% and above, full density was obtained due to reactions between boron and oxygen impurity at presence of TaC. Minor phases of TaB 2 and C were formed in the 0.24 and 0.60 wt% B compositions after gas-out of the oxygen impurity. Microstructure of the TaC ceramics was refined with increasing in boron content. The TaC ceramic with 0.24 wt% of boron showed the best mechanical properties with a Vickers hardness , flexural strength and fracture toughness of 17.7 GPa, 534 MPa and 4.6 MPa m 1/2 , respectively. When more boron was added, interfacial bonding of the TaC grains was strengthened causing a decrease in fracture toughness. Oxidation resistance of the TaC ceramics increased with boron content. Particularly, the 0.60 wt% B composition showed a weight gain of 0.0018 g/cm 2 after oxidization at 800 °C in air for 3 h.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Transactions of the Indian Ceramic Society
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2020
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IF 0.952
Hao Liu,Chuang Jie,Yan Ma,Zhoufu Wang,Xitang Wang
Suitable sintering ability and excellent densification are important factors for forsterite (Mg2SiO4) ceramics and refractories when used in glass furnaces, continuous casting tundishes, non-ferrous metal smelters, etc. Here, a dense and fine-grained structure has been obtained in the forsterite ceramics prepared by two-step sintering process. Results show that combination of grinding and second step sintering can eliminate MgSiO3 secondary phase, reduce intergranular pores and increase sintering densification of forsterite. By substituting mechanical activation for grinding, grain refinement and microstructural uniformity can be further promoted, resulting in increased bulk density and enhanced cold crushing strength. This work suggests that combination of two-step sintering and mechanical activation is effective for the preparation of forsterite ceramics with excellent densification and microstructure used in the high temperature industrial field.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2024
·
IF 4.2
Peihong He,Yulei He,Wenjia Liang,Haidong Long,Ling Ran,Peng Yang,Fang Peng
Silicon carbide (SiC) is an important structural ceramic material, exhibiting exceptional comprehensive properties that are unmatched by metals and other structural materials. In this study, a combination of α-SiC micron powder and β-SiC nanopowder was utilized as precursor materials for high pressure and high temperature (HPHT) sintering. Under a pressure of 5.0 GPa, polycrystalline SiC samples with mixed grain size were sintered within a temperature range from 1000 to 1700 °C, and compared with SiC samples sintered from single micron powder under identical temperature and pressure conditions. The microstructures of the two sets of SiC samples were observed using scanning electron microscopy. Additionally, the stress states and strengthening mechanisms among SiC grains with mixed grain size under HPHT were further analyzed in conjunction with X-ray diffraction results. The polycrystalline SiC composite ceramics sintered at 1700 °C exhibited superior mechanical and thermal properties, achieving a Vickers hardness of 35.2 GPa that is 23.5 % higher than that obtained by conventional spark plasma sintering and even surpassing the hardness of single crystal SiC, demonstrating thermal stability up to 1405 °C in air environment. Transmission electron microscopy was employed to analyze defects and plastic deformation in these samples. The study suggests that the primary strengthening mechanisms of the sintered polycrystalline SiC composite ceramics under HPHT include the increase in micro defects induced by in-situ plastic deformation at elevated temperatures and the effects of high-temperature creep. This study provides new insights into the HPHT sintering of hard materials.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2022
·
IF 4.804
Ben Chen,Zhi-Bo Li,Jun-Ru Liu,Guo-Hua Zhang
Powder metallurgy approach was used to produce fine-grain tungsten heavy alloys (WHAs), and the effect of Mo addition on the microstructures and mechanical properties of the alloy was discussed. The W-Mo-Ni-Fe ultrafine composite powders were prepared via method consisting of steps of carbothermic pre-reduction and subsequent deep hydrogen reduction. The sintered compacts of these W-Mo-Ni-Fe composite powders reached virtually full densification after sintering at 1500 °C for 2 h. It was discovered that the W grain size of WHAs reduced due to the Mo addition (0, 2.5, 5, 10 wt%). Tensile test results showed that the alloy with 5 wt% Mo exhibited the maximum ultimate tensile strength and elongation, which has a significant relationship with finer W grain size, lower W W contiguity and higher volume fraction of the γ-(Ni, Fe) matrix phase. It was also concluded that the major fracture characteristic of WHAs were transformed from W W decohesion to W-matrix interface separation with increasing the addition amount of Mo.
研究领域:
材料科学
·
冶金工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2019
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IF 4.029
Mo Yan,Xiaoming Duan,Zhuo Zhang,Xingqi Liao,Xichen Zhang,Baofu Qiu,Zengyan Wei,Peigang He,Jiancun Rao,Xiaodong Zhang,Dechang Jia,Yu Zhou
Ball milling was used on synthesized Cr 2 AlC powders, and dense Cr 2 AlC bulk ceramics with almost pure phase were fabricated by hot pressing these ball milled Cr 2 AlC powders at 1300 °C for 2 h under 30 MPa. The phase compositions and the microstructures of powders and bulk ceramics were characterized. The mechanical properties and dislocation analysis of bulk ceramics were also investigated. Our results indicated that the grain size of powders became uniform and smaller after ball milling, which was also inherited in the bulk ceramics. Moreover, the mechanical properties of hot pressed Cr 2 AlC ceramics, including flexural strength , fracture toughness, and Vickers hardness , significantly increased by using ball milled powders treated at speed 200 rpm. The organization of hexagonal dislocation networks during hot pressing and reduction of grain size both had a positive effect on improving mechanical properties.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Cheng Zhang,Runping Li,Jianhua Liu,Guo Chen,Shenghui Guo,Lei Xu,Shijie Xiao,Zhigang Shen
The effects of modification temperature and time on polyacrylonitrile (PAN) fibers under various concentrations of KMnO 4 were studied. Wettability , colouration, chemical structure (Fourier transform infrared spectroscopy), crystal structure (X-ray diffraction), stack domains (D), interlayer spacing (d), microscopic structure (Scanning electron microscopy) and elemental content (energy dispersive spectroscopy) were analysed. Aside from its good hydrophilicity, KMnO 4 at 2 and 4 wt% are beneficial to the modification of PAN fibers. The colouration of the fiber at 80 °C is the most obvious. The clear peak of the pre-oxidised fibers at 2340 cm −1 corresponds to the conjugated structure of MnO 4 –C N. At 4 wt%, the degree of pre-oxidation is too high and the main infrared peak disappears. M 2, 30 has a minimum D of 9.320 nm and 8.258 nm at 2θ = 16.883° and 2θ = 29.673°, respectively, and the fiber crystals are the finest. At a content of 4 wt%, the fibers are axially cracked and crystals appear on the surface. M 2, 30 and M 2, 60 have a close percentage of C element, whereas M 2, 30 has a lower percentage of Mn element. The best modification conditions of KMnO 4 are 2 wt%, 80 °C and 30 min.
研究领域:
材料科学
·
化学工程
✓ 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）