MECHANICAL AND TRIBOLOGICAL CHARACTERISTICS OF ALUMINIUM HYBRID COMPOSITES REINFORCED WITH BORON CARBIDE AND TITANIUM DIBORIDE

Abstract

The known superior properties in aluminium-based composites are being used in a variety of fields. The matrix adopted in this study was Al7075, and the reinforcements were boron carbide (B4C) and titanium diboride (TiB2) mixed in different amounts. The titanium diboride percentage was kept constant at 3 wt.% while the boron carbide percentage was changed. The stir casting process used to make the composites and its manufactured composites were evaluated through tests on different material properties, such as the density, hardness, compression, impact, and tensile properties. According to the results, the properties of the samples were improved when they were reinforced with 9 wt. % B4C and 3 wt. % TiB2. Scanning Electron Microscopy (SEM) was adopted to study the fracture mechanisms. The presence of dimples, cracks, and voids were clearly visible. The brittle type of fracture was also visible due to the better bonding between the matrix and the hybrid reinforcement. The Al7075 sample with 9% of B4C and 3% of TiB2 has a higher hardness value of 76HV. A maximum compressive strength of 231 MPa and maximum tensile strength of 233 MPa was achieved in the mixture of 9 wt% B4C and 3 wt% TiB2. Wear studies are used to examine the friction characteristics of manufactured samples. Experiments were conducted using the L 16 Taguchi design, with the aid of input factors such as load, sliding distance, and material type. The known output result was observed to be the coefficient of friction. An ANOVA was used to estimate the effect of the coefficient of friction with respect to the input characteristics. Finally, the morphological study of the worn surface was carried out by using SEM, while the wear track, micropits and absence of grooves were also studied.

Keywords

• aluminium
• tensile strength
• wear
• impact strength