Design of an in–situ multi–scale particles reinforced (Al2O3+ZrB2+AlN)/Al composite with high strength, elasticity modulus and thermal stability

2020 ◽  
Vol 775 ◽  
pp. 138983 ◽  
Author(s):  
Yihan Bian ◽  
Tong Gao ◽  
Guiliang Liu ◽  
Xia Ma ◽  
Yingying Ren ◽  
...  
Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4048
Author(s):  
Yihan Bian ◽  
Tong Gao ◽  
Yongfeng Zhao ◽  
Guiliang Liu ◽  
Xiangfa Liu

To synthesize Al composite with high strength at elevated temperature, high modulus and thermal stability, ZrB2, Al3BC and Al2O3 particles have been chosen as reinforcements simultaneously. A (9.2 wt.% ZrB2 + 5.6 wt.% Al3BC + 5.5 wt.% Al2O3)/Al composite has been prepared, and the in-situ synthesized particles are nano-sized. Mechanical property tests reveal that the nanoparticles exhibit a remarkable synergistic enhancement effect. The elasticity modulus of the composite is 89 GPa, and the ultimate tensile strengths at 25 °C and 350 °C can be as high as 371 MPa and 154 MPa, respectively.


2007 ◽  
Vol 539-543 ◽  
pp. 814-819 ◽  
Author(s):  
Ludovic Thilly ◽  
Vanessa Vidal ◽  
Florence Lecouturier

Copper-based high strength nanofilamentary wires reinforced by Nb nanofilaments are prepared by severe plastic deformation (repeated hot extrusion, cold drawing and bundling steps) for the winding of high pulsed magnets. The effects of microstructure refinement on the plasticity mechanisms were studied via nanoindentation, in-situ deformation in TEM and under neutron beam: all results evidence size effects in each nanostructured phase of the nanocomposite wires, i.e. single dislocation regime in the finest regions of the Cu matrix and whisker-like behaviour in the Nb nanofilaments. The macroscopic high yield stress is thus the results of the combination of the different elastic-plastic regimes of each phase that include size effects.


Author(s):  
R-R. Lee

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.


TAPPI Journal ◽  
2011 ◽  
Vol 10 (4) ◽  
pp. 29-33
Author(s):  
LEE A. GOETZ ◽  
AJI P. MATHEW ◽  
KRISTIINA OKSMAN ◽  
ARTHUR J. RAGAUSKAS

The thermal stability and decomposition of in-situ crosslinked nanocellulose whiskers – poly(methyl vinyl ether-co-maleic acid) – polyethylene glycol formulations (PMVEMA-PEG), (25%, 50%, and 75% whiskers) – were investigated using thermal gravimetric analysis (TGA) methods. The thermal degradation behavior of the films varied according to the percent cellulose whiskers in each formulation. The presence of cellulose whiskers increased the thermal stability of the PMVEMA-PEG matrix.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ayman M. Atta ◽  
Mohamed H. El-Newehy ◽  
Meera Moydeen Abdulhameed ◽  
Mohamed H. Wahby ◽  
Ahmed I. Hashem

The enhancement of both thermal and mechanical properties of epoxy materials using nanomaterials becomes a target in coating of the steel to protect it from aggressive environmental conditions for a long time, with reducing the cost. In this respect, the adhesion properties of the epoxy with the steel surfaces, and its proper superhyrophobicity to repel the seawater humidity, can be optimized via addition of green nanoparticles (NPs). In-situ modification of silver (Ag) and calcium carbonate (CaCO3) NPs with oleic acid (OA) was carried out during the formation of Ag−OA and CaCO3−OA, respectively. The epoxide oleic acid (EOA) was also used as capping for Ca−O3 NPs by in-situ method and epoxidation of Ag−OA NPs, too. The morphology, thermal stability, and the diameters of NPs, as well as their dispersion in organic solvent, were investigated. The effects of the prepared NPs on the exothermic curing of the epoxy resins in the presence of polyamines, flexibility or rigidity of epoxy coatings, wettability, and coatings durability in aggressive seawater environment were studied. The obtained results confirmed that the proper superhyrophobicity, coating adhesion, and thermal stability of the epoxy were improved after exposure to salt spray fog for 2000 h at 36 °C.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2903
Author(s):  
Juvenal Giogetti Nemaleu Deutou ◽  
Rodrigue Cyriaque Kaze ◽  
Elie Kamseu ◽  
Vincenzo M. Sglavo

The present project investigated the thermal stability of cold-setting refractory composites under high-temperature cycles. The proposed route dealt with the feasibility of using fillers with different particle sizes and studying their influence on the thermo-mechanical properties of refractory geopolymer composites. The volumetric shrinkage was studied with respect to particle sizes of fillers (80, 200 and 500 µm), treatment temperature (1050–1250 °C) and amount of fillers (70–85 wt.%). The results, combined with thermal analysis, indicated the efficiency of refractory-based kyanite aggregates for enhancing thermo-mechanical properties. At low temperatures, larger amounts of kyanite aggregates promoted mechanical strength development. Flexural strengths of 45, 42 and 40 MPa were obtained for geopolymer samples, respectively, at 1200 °C, made with filler particles sieved at 80, 200 and 500 µm. In addition, a sintering temperature equal to 1200 °C appeared beneficial for the promotion of densification as well as bonding between kyanite aggregates and the matrix, contributing to the reinforcement of the refractory geopolymer composites without any sign of vitrification. From the obtained properties of thermal stability, good densification and high strength, kyanite aggregates are efficient and promising candidates for the production of environmentally friendly, castable refractory composites.


RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20486-20497
Author(s):  
Zhiyan Liu ◽  
Rui Ma ◽  
Wenjie Du ◽  
Gang Yang ◽  
Tao Chen

Chitosan hydrogel is regenerated from alkali/urea aqueous solution and the lithium sulfonate second network is introduced by electron beam radiation-initiated in situ free radical polymerization. The freeze-dried aerogel has CO2 capture capacity.


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