Development of models for predicting impact strength of Al7075/Al₂O₃ composites produced by stir-casting

Abstract

Aluminium matrix based metal matrix composites (MMCs) are being extensively used in various industrial applications that need high strength combined with low weight, high hardness, wear resistance, high temperature resistance, improved impact strength, etc. They are amenable to secondary manufacturing processes such as extrusion, rolling, forging, welding, etc. However, because of their complex nature, both in terms of composition and difficulty in manufacturing by the standard fabrication techniques, researchers are keen to study various combinations of constituent materials -matrix and reinforcement, their processing, property evaluation, and extending their applications in various fields. This article presents the details of the investigation comprising stir casting of Al7075 matrix material reinforced with Al 2 O 3 particulates. An attempt has been made to predict the impact strength of these MMCs, which is an important property that decides their suitability in shock loading environment, both in the as-cast and forged conditions. Multi-factor, rotatable, central composite design has been used to predict the impact strength in terms of charpy-V. The mathematical models developed are validated using Fisher's F-test.

Comparative study on the mechanical and microstructural characterisation of AA 7075 nano and hybrid nanocomposites produced by stir and squeeze casting

“…The squeeze cast process can reduce the pores and defects to a higher magnitude than stir casting. Moreover, it ensures the stronger bond between matrix and reinforcements and grain refinement [48] . All these effects collectively result in more ductile material that might have increased the impact strength of the squeeze cast nanocomposite.…”

Low-velocity impact behavior of Al 6061/SiC particulate metal matrix composites

“…Therefore, the response of impact loading is also an important design parameter for these materials to use them with confidence in service conditions. [8][9][10] The literature survey shows that there is only limited number of experimental studies [11][12][13][14][15][16][17][18][19][20][21] and almost no numerical studies about impact behavior of these materials, even though a number of quasi-static mechanical properties of particle reinforced metal matrix composites have been considerably investigated with both experimental and numerical studies. It is very important to dissipate the lack of information with regard to impact behavior, which can limit the industrial applications of these composites by carrying out comprehensive studies.…”

Effects of reinforcing particle size and interface bonding strength on tensile properties and fracture behavior of Al-A206/alumina micro/nanocomposites

“…While conventional stir mixing followed by casting is one of the most economical techniques available to produce large near-net shape parts from MMCs, it is generally assumed that this method cannot be used to synthesize nanocomposites. [4][5][6] Melting process has two major problems, firstly, ceramic particles are generally not wetted by liquid metal matrix, and secondly, the particles tend to sink or float depending on their density relative to liquid metal. Therefore, the dispersion of ceramic particles is not uniform, whereas powder metallurgy makes the uniform dispersion of reinforcement in the matrix.…”