Effect of h-Boron Nitrate on Microstructure and Mechanical Behavior of Al7075 Metal Matrix Composite Producing by Stir Casting Technique

Abstract

Al7075 alloy reinforced with h-Boron Nitrate (BN) composites were processed by stir casting technique. The produced composite was subjected to microstructural studies using OLYMPUS-BX51M, tensile, hardness, density and wear tests. Tensile strength and hardness were found to increase by 12.8% and 20% respectively due to increased dislocation density with the addition of reinforcement. Microstructure showed grain refinement with reinforcement addition and reinforcement acts as nucleating sites with an approximately uniform distribution of reinforcements. Wear test was conducted with different loads 10, 20 and 30N for a sliding distance of 1500 m. Wear mass loss of composites showed improved wear resistance with variation in reinforcements. Worn surfaces were examined using SEM, which showed the presence of delamination, plough and debris on the surface. Due to the addition of low-density h-BN, the density of composites decreases with increase in reinforcement content.

A comparative study on the mechanical and tribological characteristics of AA7075/h-BN and AA7075/h-BN/MoS2 hybrid nano-composites produced using stir-squeeze casting process

“…The lengths of the dendrites are also found elongated in the microstructure, which is due to the rapid solidification process. The present microstructure of AA7075 is similar to the results referred in the recent articles [9,11,20,42,43,47,48].…”

“…The improvement in the hardness value enhances the tribological properties both in terms of wear resistance and low CoF. However, the addition of a higher volume percentage of h-BN leads to certain drawbacks like porosity, voids, clusters, agglomeration, and brittleness [47]. The researchers have not investigated the addition of h-BN particles below 3 wt.% in AA7075.…”

Tribological performance evaluation of h-BN nanoparticle reinforced AA 7075 and as-cast AA7075 using Taguchi and genetic algorithm

“…There is an exhibition of interdendritic pattern of elongated grains in the microstructure of as-cast AA7075 (Refer figure 1(a)). As a result of the rapid solidification, the dendrite lengths are found to be elongated for the as-cast AA7075, similar to the recent studies [40,41,50]. The addition of h-BN nanoparticles has undoubtedly influenced the microstructure changes of AA7075/h-BN MMCs.…”

“…In addition, the h-BN nanoparticles decrease the co-efficient of thermal expansion (CTE) as well as increase the damping capacity in-contrast to pure AA [38]. Similarly, the hardness, UTS, and wear resistance of Al 7075 alloy increases with inclusion of h-BN particles [40]. From the existing literature it is observed that the addition of h-BN particles below 3 wt% in AA7075 is not investigated.…”

Metallurgical and Mechanical Properties of Laser Cladded AlFeCuCrCoNi-WC10 High Entropy Alloy Coating

“…Therefore, the temperature difference (∆t) is very high, while the solidification rate (r) is less, which tends to give large ∆t/r. Therefore, the nucleation rate is much quicker than the growth rate of the crystal and it will lead to grow as the planar crystal at the interface [16][17][18]. The growth direction of the columnar grain is perpendicular to the interface zone due to the rapid directional solidification, typical of the laser cladding process [19].…”