Herein, in-situ sintered micro-nano Ti2AlC/TiAl composite with fully lamellar structures were designed by spark plasma sintering to improve the high-temperature oxidation resistance of TiAl alloys. ...The Ti2AlC/TiAl composite exhibited lower oxidation rate and thinner oxide scale enriched Al2O3 compared to TiAl alloy after 750 ℃ and 850 ℃ oxidation, suggesting that oxidation resistance of the Ti2AlC/TiAl composite was improved. The superior oxidation resistance of the Ti2AlC/TiAl composite was mainly attributed to Ti2AlC particles hindered the diffusion of O atoms and stabilized the Al-rich oxide layer by the formation of more Ti-Al-N layers due to the nitridation susceptibility of Ti2AlC.
•Micro-nano Ti2AlC reinforced TiAl composites were synthesized by SPS.•The Ti2AlC/TiAl composites show superior high temperature oxidation resistance.•In-situ precipitated Ti2AlC at the interface of α2 and γ lamella inhibits the diffusion of oxygen.
Binderless WC matrix cemented carbide was considered a novel material with the potential to replace WC-Co cemented carbide. However, current research was insufficient to address the trade-off between ...strength, toughness, and strength in binderless WC matrix cemented carbide. In this work, the machine learning was employed to estimate mechanical property and optimize the composition of WC matrix cemented carbide. WC-MgO-ZrO2 composites were successfully developed with uniform microstructure and excellent mechanical properties. The experimental results showed that the grain size of WC reached 1.05μm where the mass fraction of ZrO2 was 2%. The WC-MgO-2 wt%ZrO2 composite exhibited superior Vickers hardness, fracture toughness, and flexural fracture strength, which were 1851HV, 11.2 MPa·m1/2 and 1368 MPa, respectively. The fracture mode of WC-MgO-ZrO2 composites was mainly a mixture of transgranular fracture and intergranular fracture. The main toughening mechanisms were crack deflection, crack bridging, grain pull out and phase transformation. The comprehensive mechanical properties of WC-MgO-2 wt%ZrO2 composites rank at a superior level compared to similar binderless WC matrix composites reported in the current literature. Meanwhile, the wear behaviors of WC-MgO-ZrO2 composites were examined under three different loads. And the wear behavior and mechanism of WC MgO-2 wt% ZrO2 composite were revealed.
Metallic glasses present remarkable characteristics such as mechanical properties, wear, corrosion resistance, and biocompatibility, among others, but their production is still limited to bulk ...materials. In this work, the Spark Plasma Sintering technique is used to elaborate Fe-based Bulk metallic glass. The densification, hardness, fracture toughness, and wear resistance are adjusted with the addition of 1 wt% Al2O3 particles of different sizes. The alumina particles were mixed with the metallic particles. All the samples were sintered with a maximum temperature of 560 °C and a pressure of 300 MPa. The addition of micro-sized alumina particles (30 µm) positively affected the samples' hardness, wear resistance, and fracture toughness. However, the nano-sized particles (50 nm) and fume particles (≥ 30 nm) did not show an improvement in hardness, density, or wear resistance but did show increased fracture toughness in the material. Young's modulus was not adversely affected when the ceramic particles were added to the metallic glass matrix.
A rising interest in entropy-stabilized oxides in recent years has been driven by their attractive functional properties. Their synthesis usually requires prolonged exposure at high temperature to ...promote solid-state diffusion without the application of pressure. In this work, we report the synthesis of a high entropy perovskite, Sr((Zr
0.94
Y
0.06
)
0.2
Sn
0.2
Ti
0.2
Hf
0.2
Mn
0.2
)O
3−
x
, in a relatively short time (minutes instead of hours) using a spark plasma sintering (SPS) furnace. Comparative analysis showed that conventional pressureless sintering at 1500°C for 2 h results in porous materials with large thermodynamically stable pores (tens of µm), while SPS processing produces dense materials in a single step by reactive sintering at 1475°C in 9 min. SPS is therefore an attractive route for the production, synthesis and sintering of dense high-entropy oxides.
We developed BaCl2:Yb transparent ceramics by the spark plasma sintering method and evaluated their optical and scintillation properties. An emission peak in the photoluminescence and scintillation ...spectra was observed at 440 nm due to the spin-forbidden 4f135d1–4f14 transition of Yb2+. The afterglow levels of the BaCl2:Yb transparent ceramics were lower than those of a commonly used inorganic scintillator CsI:Tl and CdWO4. The scintillation light yield of the 0.5% doped BaCl2:Yb transparent ceramic was 2400 ph/MeV under 137Cs γ-ray irradiation, and the value is low in comparison with those of other Yb-doped halide materials.
•BaCl2:Yb transparent ceramics were fabricated to evaluate the scintillation properties.•The scintillation peak due to 4f135d1–4f14 transition of Yb2+ was observed at 440 nm.•The afterglow levels were better than those of practical X-ray scintillators such as CsI:Tl.•The 0.5% BaCl2:Yb sample showed the highest light yield (2400 ph/MeV) under 137Cs γ-ray irradiation in the samples.
The feasibility of flash joining conductive ceramics using spark plasma sintering is demonstrated. It is shown that graphite disks can be joined in a few seconds (6–10 s electric discharge time) ...using a SiOC precursor (methyl silicone resin) as an interlayer. Differently from usual flash experiments, the process does not require any pre-heating, allowing a dramatic reduction of the processing time. XPS analysis of the joint revealed a clear evolution of the chemical environment of silicon with a progressive transition from SiOC to SiO2/SiC. Mechanical tests were performed to determine the fracture toughness (1.0 ± 0.2 MPa m0.5) and fracture energy (40.6 ± 9.8 J/m2) of the interface
Flash joining can be applied beyond graphite joining, and opens a novel and flexible processing route for many conductive ceramics, as demonstrate by preliminary work on Kanthal® Super MoSi2 and Cf-reinforced SiC.
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