scholarly journals In Situ Synthesis of Core-Shell-Structured SiCp Reinforcements in Aluminium Matrix Composites by Powder Metallurgy

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1201
Author(s):  
Xinghua Ji ◽  
Cheng Zhang ◽  
Shufeng Li
Keyword(s):  
Particle Size ◽  
Powder Metallurgy ◽  
Shell Structure ◽  
Ex Situ ◽  
Aluminium Matrix ◽  
Core Shell ◽  
Matrix Composites ◽  
Aluminium Matrix Composites ◽  
Core Shell Structure

SiCp reinforced aluminium matrix composites (AMCs), which are widely used in the aerospace, automotive, and electronic packaging fields along with others, are usually prepared by ex situ techniques. However, interfacial contamination and poor wettability of the ex situ techniques make further improvement in their comprehensive performance difficult. In this paper, SiCp reinforced AMCs with theoretical volume fractions of 15, 20, and 30% are prepared by powder metallurgy and in situ reaction via an Al-Si-C system. Moreover, a combined method of external addition and an in situ method is used to investigate the synergistic effect of ex situ and in situ SiCp on AMCs. SiC particles can be formed by an indirect reaction: 4Al + 3C → Al4C3 and Al4C3 + 3Si → 3SiC + 4Al. This reaction is mainly through the diffusion of Si, in which Si diffuses around Al4C3 and then reacts with Al4C3 to form SiCp. The in situ SiC particles have a smooth boundary, and the particle size is approximately 1–3 μm. A core-shell structure having good bonding with an aluminium matrix was generated, which consists of an ex situ SiC core and an in situ SiC shell with a thickness of 1–5 μm. The yield strength and ultimate tensile strength of in situ SiCp reinforced AMCs can be significantly increased with a constant ductility by adding 5% ex situ SiCp for Al-28Si-7C. The graphite particle size has a significant effect on the properties of the alloy. A criterion to determine whether Al4C3 is a complete reaction is achieved, and the forming mechanism of the core-shell structure is analysed.

Reaction Mechanism of Iron-Rich Magnesia-Corundum Composites at 1420°C

2016 ◽  
Vol 680 ◽  
pp. 339-342 ◽  
Author(s):  
Hao Bo Zhang ◽  
Yong Li ◽  
Jia Lin Sun ◽  
Shuo Cao ◽  
Yong Qiang Sun ◽  
...  
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Reaction Mechanism ◽  
Low Temperature ◽  
Shell Structure ◽  
Core Shell ◽  
Spinel Solid Solution ◽  
Core Shell Structure ◽  
Periclase Material

Specimens were prepared by using iron-rich magnesia and high-pure magnesia as the main starting materials, and introducing fused corundum of 3%(in mass), 6%, 9%, 12%, 15% respectively and sintered at 1420°C.The samples were characterized by XRD and SEM. The results show that in-situ synthesized composite spinel solid solution were formed in the reaction between iron-rich magnesia and fused corundum. Iron oxides play a key role on the formation of spinel solid solution. When fused corundum was added in a certain particle size, the material showed core-shell structure. Outer layer of core-shell structure were spinel solid solution and the inside were corundum. These core-shell structure make the synthesis of spinel solid solution bonded periclase material at low temperature happen.

Research of In Situ Polymerization and Core-Shell Structure Modified Emulsified Asphalt

2011 ◽  
Vol 71-78 ◽  
pp. 928-931
Author(s):  
Jin Liang Wu ◽  
Yong Xing Zhang ◽  
Chun Sun Zhang
Keyword(s):  
Shell Structure ◽  
In Situ Polymerization ◽  
Core Shell ◽  
Asphalt Emulsion ◽  
Sound Effect ◽  
Structure And Property ◽  
Modified Asphalt ◽  
Core Shell Structure ◽  
Emulsified Asphalt

Nowadays, there are dominantly two ways of producing modified emulsified asphalt ,one of which is to emulsify modified asphalt, the other to modify asphalt emulsion. But they have the same defect that modifier cannot be evenly mixed with asphalt emulsion, which has side effect on the performance of modified emulsified asphalt. The emulsified asphalt and modifier have different traits in structure and property. In order to make the modifier disperse in asphalt emulsion evenly to improve the performance of modified emulsified asphalt, a tentative idea is brought forward: we shall utilize in-situ polymerization and core-shell structure to enhance feature of emulsified asphalt. Core-shell structure is a method of synthesizing composite material, which can assist to achieve sound effect of the two kinds of materials. The point to emphasize is, in this paper, the introduction and feasibility of the method, its specialty against current mainly methods, the difficulties encountered in practice as well as its promising prospect and the anticipated target to achieve will all be illustrated.

Friction Stir Welding of the Aluminum Matrix Composite - A Literature Review

2015 ◽  
Vol 787 ◽  
pp. 669-673
Author(s):  
K. Reddi Prasad ◽  
Arumugam Mahamani
Keyword(s):  
Friction Stir Welding ◽  
Literature Review ◽  
Weight Ratio ◽  
Ex Situ ◽  
Aluminium Matrix ◽  
Matrix Composites ◽  
Aluminium Matrix Composites ◽  
Friction Stir ◽  
Joint Efficiency ◽  
Welding Processes

Aluminium matrix composites have received the attention of numerous researchers, because of its attractive properties like high strength, good thermal conductivity and more strength to weight ratio. Application of the conventional welding processes for aluminium matrix composites, facilitates the formation of undesirable phase at the welded region, which limits the wide spread application. The objective of this paper is to review the literatures belonging to the friction stir welding of the composites and explore the challenges associated to maximize joint efficiency. The major contribution of this paper is to study the issue of welding of ex-situ and in-situ composites, various process parameters, properties of joint and post weld heat treatment process to improve the joint efficiency. This literature review provides some research gaps in the friction stir welding of composites.

In situ fabricated metal-carbide with core–shell structure for high impact-toughness iron-matrix composite

2019 ◽  
Vol 35 (14) ◽  
pp. 1727-1734
Author(s):  
Lisheng Zhong ◽  
Haiqiang Bai ◽  
Junzhe Wei ◽  
Jianlei Zhu ◽  
Jianhong Peng ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Matrix Composite ◽  
Shell Structure ◽  
High Impact ◽  
Core Shell ◽  
Metal Carbide ◽  
Iron Matrix ◽  
Fabricated Metal ◽  
Core Shell Structure

Novel conductive core–shell particles of elastomeric nanoparticles coated with polypyrrole

RSC Advances ◽  
2015 ◽  
Vol 5 (120) ◽  
pp. 98904-98909 ◽  
Author(s):  
Jiangru Zhang ◽  
Guicun Qi ◽  
Xiang Wang ◽  
Binghai Li ◽  
Zhihai Song ◽  
...  
Keyword(s):  
Shell Structure ◽  
Oxidative Polymerization ◽  
Core Shell ◽  
Conductive Particle ◽  
Core Shell Structure ◽  
Shell Particles ◽  
First Time

For the first time, an ultrafine conductive particle with core–shell structure, acrylonitrile-butadiene elastomeric nanoparticle (NBR-ENP) coated with polypyrrole (PPy), was prepared by in situ oxidative polymerization.

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