Particle distribution and interfacial reactions of Al–7%Si–10%B4C die casting composite

Zhang, Zhan; Chen, X.-G.; Charette, André B.

doi:10.1007/s10853-007-1554-5

Cited by 45 publications

(31 citation statements)

References 11 publications

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“…In general, a non-uniform distribution of particles in the aluminum matrix and the presence of these particles increase the viscosity of melt, resulting in decrease of fluidity [29] . Moreover, controlled particle distribution in the matrix is very important for composite material applications since it greatly impacts the mechanical properties such as tensile strength and elongation of the materials ^ .…”

Section: Particle Distributionmentioning

confidence: 99%

Investigation and characterization of fluidity and microstructure of recycled AL-B4C materials /

Shi¹

2010

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In recent years, AI-B4C Metal Matrix Composites (MMCs) have been increasingly used as neutron absorber components in the nuclear industry. During manufacturing processes, the process scrap from the casting and transformation processes (extrusion and rolling) can reach 50 to 60% of the total materials produced. The need to recycle AI-B4C composites becomes more urgent to meet environmental goals and to reduce the production costs. Remelting is a promising method to recycle process scrap materials because of its simplicity. For the liquid metal casting process, good fluidity is a basic requirement for the materials to be recycled with the remelting process. The reinforcement characteristics such as size, shape and volume fraction of ceramic particles have an effect on the fluidity of Al-based composites. Moreover, the particle agglomerates, particle settling and pushing, presence of oxide films, and the appearance of reaction-induced particles influence the flow behavior of the composite melt.The study presented in this thesis was carried out to investigate the fluidity evolution of AI-B4C recycled scrap. In this project, the fluidity evolution of scrap from AA6063-10 vol.% B 4 C cast billets and extruded plates, as well as AA1100-16 vol.% B 4 C cast ingots and rolled sheets is investigated by means of vacuum fluidity tests. In order to understand the different materials, the microstructure evolution of original materials, crucible samples, as well as fluidity samples as different holding times is examined with optical and electron microscopes. The morphology and distribution of the B4C particles and its reaction products in these samples are quantitatively characterized by an image analyzer. Furthermore, the influence of microstructure on fluidity behavior of these materials is discussed.The methods for characterization of AI-B4C composites microstructure are developed in this research. These methods have been successfully applied to describe and quantitatively analyze the particle volume fraction, distribution, agglomeration and particle effective volume fraction. General image analysis techniques are introduced to distinct particles for subsequent quantitative measurements. An appropriate homogeneity parameter P for charactering the distribution homogeneity is proposed to be the ratio of variance of distribution of cell areas to the corresponding variance obtained from a random particle distribution with the same amount of particles. The particle agglomerates in the form of clusters and networks induced by oxide films are identified. And the effective volume fraction of particles is introduced to reflect the flow resistance of particle segregation and agglomeration in the AI-B4C MMC microstructure.The results show that the fluidity of either cast or extruded AA6063-10 vol.% B4C metal matrix composites decreases with the increase of the holding time. The fluidity decline of the cast billets is much faster than that of the extruded plates during the melt holding period (8.5 h). The microstructures of orig...

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Section: Particle Distributionmentioning

confidence: 99%

Investigation and characterization of fluidity and microstructure of recycled AL-B4C materials /

Shi¹

2010

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“…Later it has been proposed that secondary reactions phases AI3BC and AIB2 formed by following equation [Zhang et al, 2008a;Zhang et al, 2007;Viala et al, 1997].…”

Section: Addition Of Titaniummentioning

confidence: 99%

“…However the sizes of the particles were too small to obtain accurate quantitative data (see Fig.5.21). et al, 2008a;Zhang et al, 2007;Viala et al, 1997].…”

Section: Surface Tension Calculation For Al and Al-ti Alloymentioning

confidence: 99%

Investigation on wetting of B4C by aluminum alloys /

Sarkar¹

2009

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Aluminum-B4C composites (MMC) gained importance in aluminum industry because it can be used in high performance applications such as radioactive nuclear waste storage, aircraft and aerospace structures due to its neutron shielding capacity, light weight, high strength, and stiffness. It is difficult to mix B4C powder with liquid aluminum to produce composites due to poor wettability of B4C. In addition, B4C is not stable when it is in contact with aluminum. The optical microscopy and scanning electron microscopy analyses of the interface revealed the formation of AI3BC and AÎB2 particles around the B4C particle. This reaction is continuous and results in the depletion of B4C concentration, decrease in the fluidity of the melt, and deterioration in its mechanical and physical properties. To prevent B4C loss, titanium is added to aluminum. Ti has affinity to react with B4C and forms a protective layer around the particle.Objectives of this project are to investigate the wettability of B4C/aluminum and B4C/aluminum-titaniurn alloy systems, and to identify other potential alloying elements to protect B4C. The sessile-drop experiments have been conducted to measure the contact angles of B4C as well as those of the interfacial reaction products forming due to the presence of alloying elements in aluminum. Also, the effect of Ti content on the wettability of B4C by aluminum was studied.The results of the experiments show that the titanium and zirconium addition to aluminum has a strong positive effect on wetting between B4C particles and the liquid metal. In order to understand the effects of the reaction products on wetting, the contact angles between the reaction products (TiC, T1B2, AIB2 and AI4C3 particles) and aluminum have been measured at 750°C and 850°C. The results also show that wetting increases with increasing temperature and contact time.It is found out that with Ti addition, AIB2 particles disappear and new Ti-rich needle-like particles (TiB?) are formed around the B4C particles. These act as a barrier layer which isolates the B4C from the aluminum matrix. It is also observed that with increasing Ti content, the formation of AI3BC decreases. However, further increase in Ti content causes

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“…However this problem can be avoided due to the melting point of Al at 660 o C. Al-Si-Mg alloy was chosen in this study because of Si is a common element to strengthen the Al besides Si plays important roles in the formation of a dense barrier layer that can limit B 4 C decomposition and improve B 4 C stability in the aluminium melt [9]. According to Zhang et.…”

Section: Introductionmentioning

confidence: 99%

“…al. [9], there are two main manufacturing processes for aluminium based metal matrix composite i.e. the liquid mixing process and powder metallurgy process.…”

Section: Introductionmentioning

confidence: 99%

Neutron absorption of Al-Si-Mg-B4C composite

Abdullah¹,

Ibrahim²,

Daud³

et al. 2016

AIP Conference Proceedings

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Abstract. Al-Si-Mg-B4C composites containing 2-8 wt% of B4C were prepared by stir casting technique. Homogenization treatment was carried out at temperatures of 540 o C for 4 houra and followed by ageing at 180 o C for 2 houra. Microstructure and phase identification were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. Neutron absorption study was investigated using neutron source Am/Be 241 . The result indicated that higher B4C content improved the neutron absorption property. Meanwhile homogeneity of the composite was increased by ageing processes. This composite is potential to be used as neutron shielding material especially for nuclear reactor application.

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Particle distribution and interfacial reactions of Al–7%Si–10%B4C die casting composite

Cited by 45 publications

References 11 publications

Investigation and characterization of fluidity and microstructure of recycled AL-B4C materials /

Investigation and characterization of fluidity and microstructure of recycled AL-B4C materials /

Investigation on wetting of B4C by aluminum alloys /

Neutron absorption of Al-Si-Mg-B4C composite

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