Issue 63

S. R. Sreenivasa Iyengar et alii, Frattura ed Integrità Strutturale, 63 (2023) 289-300; DOI: 10.3221/IGF-ESIS.63.22

I NTRODUCTION

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wo dissimilar materials are combined together and which makes one of a kind new material known as composite [1]. Aluminum Matrix Composites (AMC) are used worldwide in variety of mechanical and wear applications due to their superior properties like better strength-to-weight-ratio, hardness, low density, excellent wear resistance & stable properties at higher temperature [2-4]. Due to ease of recycling nature and being non-toxic aluminum alloys, they are finding extensive commercial applications in various areas such as automobile, space craft and structural industries where component weight reduction is the main objective [5-7]. Many research works have been done in developing Aluminum composites with different combinations of reinforcements. Sridhar Raja et al. [8] evaluated the effect of TiB 2 on micro-structural and mechanical characteristics of Al Composite. The outcomes revealed that, enhancement of tensile strength and hardness of the MMCs was observed with the increase in the reinforcement content. R Balachandar et al. [2] evaluated the mechanical characteristics of Al 6xxx reinforced with magnesium and rock dust using different weight % of composites produced by Stir Casting technique. From the outcomes it was observed that, addition of AZ31 led to increase in tensile Strength and rock dust content led to decrease in the density of developed composites. S. Gopalakrishnan et al. [9] revealed that wear rate increased by increasing in applied load. But, the wear rate reduced by increasing the TiC content. Xuedan Dong et al. [10] studied the effect of CeO 2 particulates on micro-structure and mechanical behavior of Al composites. The outcomes showed that the presence of the suitable wt. % of CeO 2 increased the tensile strength of the MMCs. Chao Liu et al. [11] evaluated the effects of CeO 2 on the mechanical behavior. The outcomes showed that the presence of CeO 2 led to enhancement in the mechanical behavior of the Al alloys. By increasing wt. % of CeO 2 , all the composites samples showed the trend of increasing in the mechanical properties of Al but, porosities attained the maximum value. Reddappa et al. [12] observed that the specific wear loss has decreased with increasing wt. % of beryl content. A. Anilkumar et al. [13] analyzed that the specific wear rate reduced by increase in Beryl/CeO 2 content. SEM was used to study the uniform dispersal of Beryl-CeO 2 particulates in Al6061. R. Saravanan [14] in his research work focused on the studies relating to wear and mechanical properties of Al reinforced with CeO 2 and TiB 2 . MMC’s were prepared using stircasting technique. Here, cast parts were subjected to hot-rolling at the temperature of 515°C to reduce the thickness of developed composites from 10mm to 5mm in 12 passes. From the outcomes it was found that, the developed composite properties were enhanced by addition of reinforcement content. Amra et al. [15] evaluated the mechanical properties of CeO 2 - SiC reinforced Al Composites. This study was aimed to manufacture Al composites with improved mechanical properties by the addition of CeO 2 - SiC reinforcement particulates into the Al. Chicet et al. [16] summarized that, the inter conditioning parameters of contact fatigue in the case of a rolling and sliding contact depending on: – surface quality: micro defects; microcracks; material detachments; porosity; pitting; flaking; large detachments (spalling); plastic flows; – the appearance, from the depth to the surface, of the micro defects, microcracks; cracks; – material properties: modulus of elasticity; hardness; fatigue resistance; – lubricant properties: viscosity; degree of contamination; – load applied to the surface: load size; the meaning of application; mode of variation. Abuthakir et al. [17] SEM analysis of composites in the peak aged (T6) condition revealed that the amount of AlNi intermetallic phase formed increased with an increase in weight fraction of Ni particles since the number of heterogeneous nucleation sites were increased. It can be said that AA6061 + 1.5 Wt% Ni composite has higher amount of AlNi intermetallic reinforcements. The increased amount of AlNi intermetallic phase in the composites with increasing weight fraction of Ni particles can be attributed to dissolution of Ni particles in the peak aged (T6) condition. This resulted in higher hardness and more effective grain refinement of composites than the base alloy in the peak aged (T6) condition. Though, from the literature survey it is found that sufficient data on hot rolled hybrid composites is not available on the mechanical properties of Al6061 MMCs. So, the current research work aims at study of micro-structure, hardness, tensile strength and wear characteristics of the hot-rolled hybrid AMMCs (Al6061+TiB 2 +CeO 2 ) having different wt. % of reinforcement. The fractography of the fractured surface of tensile and wear test specimens were analyzed through SEM study.

R AW MATERIALS

Matrix and Reinforcements luminium 6061 is a precipitation-hardened alloy whose major alloying element is silicon (Si) and magnesium (Mg). Alloy 6061 sets the standard from the other alloys on account for its lightweight, medium-to-high strength and it provides an excellent corrosion resistance when exposed to atmosphere and sea water [9, 17].

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