Effect of volume fraction and size of B₄C particles on production and microstructure properties of B₄C reinforced aluminium alloy composites

Abstract

A stir casting process was developed to produce aluminium alloy composites containing two different sizes and volume fractions of B4C particles up to 10 vol.-. Manufacturing of B4C particle reinforced 2024 aluminium alloy composites was modified so as to reduce the processing temperature. In the present study, in order to improve incorporation of the B4C particles by 2024 aluminium alloy melt, a novel pretreatment process before stir casting was attempted, and a significant improvement was gained. This finding showed that the treatment modified the surface condition of boron carbide powders via the removal of oxides. The comparison of added and incorporated particle ratios (the yield rate) indicated that the amount of incorporated particles decreased with increasing volume fraction and decreasing size of particles. Scanning electron microscopic observations of the microstructures revealed that the dispersion of the coarser sizes of particles was more uniform, while finer particles led to agglomeration of the particles and porosity. The results showed that the density of the composites decreased with increasing particle volume fraction and decreasing particle size, whereas the porosity and hardness values increased with increasing particle volume fraction and decreasing particle size.

Microstructural, mechanical and tribological characterization on the Al based functionally graded material fabricated powder metallurgy

“…The melt-stirring process is the liquid state process that can be used for a variety of materials [11]. Stir casting is considered as one of the most employed liquid state processing because it has a simple procedure and provides some benefits like good wettability, maximum yield, less porosity and less damage to reinforcement [12].…”

Electrochemical Behavior of Al-B4C Metal Matrix Composites in NaCl Solution

“…These features make B 4 C an excellent reinforcement for high performance MMCs. Its applications include hard disc substrates, brakes with a high wear resistance and armor plates with a high ballistic performance [9,10]. In recent years, due to the special capturing neutron ability of isotope B 10 , Al-B 4 C MMCs have been increasingly used as neutron shielding materials when fabricating storage containers for spent nuclear fuels in the nuclear industry [11,12,13,14].…”

A Novel Method for Incorporation of Micron-Sized SiC Particles into Molten Pure Aluminum Utilizing a Co Coating

“…However, methods of achieving the following in stir casting are mostly to be considered: (i) no adverse chemical reaction between the reinforcement material and matrix alloy, (ii) no or very low porosity in the cast AMMCs, (iii) wettability between the two main phases, and (iv) achieving a uniform distribution of the reinforcement material. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Some of the methods used to achieve these goals during stir casting of aluminum matrix composites are the modification of the alloy composition, coating or specific treatments to the reinforcements, and control of the process parameters (stirring temperature and time, etc.). [11][12][13][14] Among these, coating of the reinforcement is a successful technique used to prevent adverse interfacial reaction and promote wetting of the particles by aluminum through increasing the overall surface energy of the solid.…”

“…Due to these advantages, they are used in aerospace industries (airframe and aerospace components), automobile industries (engine pistons), and electronic components. [1][2][3][4][5][6][7][8] Many techniques have been developed for producing particulate-reinforced AMMCs, such as stir casting, squeeze casting, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and powder metallurgy. [19][20][21] Although each of these methods has its own advantages and disadvantages, they are all relatively expensive.…”