Materials Research Express (Jan 2020)
Characterization, corrosion and failure strength analysis of Al7075 influenced with B4C and Nano-Al2O3 composite using online acoustic emission
Abstract
This paper aims to establish the mechanical, corrosion and failure analysis using online acoustic emission of Al7075 alloy, Al7075-B _4 C composite and Al7075- B _4 C-Al _2 O _3 hybrid composite with different Boron Carbide (B _4 C) content of 5, 10, 15 & 20% and Nano Aluminium Oxide (Al _2 O _3 ) content of 2 % on a weight basis with the high energy stir casting method. The casted samples have been characterized by x-ray Diffraction (XRD), Thermo gravimetric analysis (TGA/DSC), Energy Dispersive Spectrum (EDS), and Scanning Electron Microscope (SEM). In case of hybrid composite, the hardness and the tensile strength decrease when the content of Al _2 O _3 increases. However, in the present research, the addition of B _4 C with nano Al _2 O _3 particles in certain proportions has increased the hardness and tensile strength. In addition, the tensile fractographs of the specimens were analysed using SEM. Acoustic Emission (AE) method was used for monitoring the acoustic energy that are released at the time of deformation process and early crack detection. The influence of the volume fraction of the B _4 C particulates on the microstructural and corrosion characteristics of Al7075- B _4 C with nano Al _2 O _3 metal matrix composites (MMCs) was also studied. It has been observed from the literature that the direct strengthening of composites occurs due to the presence of hard ceramic phase, while the indirect strengthening arises from the thermal mismatch between the matrix alloy and reinforcing phase during solidification. Based on the database for material properties, the application area of HAMCs has been proposed in the present review. The effects of nanomaterial dispersion in the metal matrix and the formation of interfacial precipitates on these properties are also addressed. Particular attention is paid to the fundamentals and the structure–property relationships of such novel Nano composites.
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