Issue 62

G. Veeresha et alii, Frattura ed Integrità Strutturale, 62 (2022) 385-407; DOI: 10.3221/IGF-ESIS.62.27

metal is agitated to a degree of vortex generation by rotating the stirrer at a speed of about 300 rpm. Side by side B 4 C particles equivalent to 2 wt. percent by weight of charged Al2618 are preheated in a separate heater to 400°C and injected gently into the molten metal vortex in phases while churning the molten metal. The stirring process is continued until perfect wettability between the Al2618 alloy matrix and the B 4 C reinforce particles is achieved, resulting in interfacial shear strength. The molten metal comprising Al2618 alloy matrix and B 4 C reinforce particles is then poured into cast iron molds of 120 mm of length and dia., of 15 mm. The same procedure is used to make composites with B 4 C particles in various weight %. The prepared composites of Al2618 alloy with B 4 C are shown in Fig. 2.

Figure 2: Al2618 alloy with B 4 C composite.

The specimen is arranged for microstructural analysis using a SEM after casting to determine the uniform circulation of reinforcing particles in the Al2618 alloy. Microstructures of Al2618 alloy and Al2618 with different percentages of B 4 C reinforced composites are captured. Microstructure specimen dimensions are 15 mm in dia., and 5 mm in height. 240, 600, and 800 grit paper are used to grind the specimen's surface. The surface is then polished with polishing paper (4 micron) for a smoother finish using a polishing machine. Following that, the samples are cleaned with distilled water to eliminate any dirt or other impurities that may have accumulated on the polished surface. Keller’s reagent is utilized to etch the specimens to create a contrast surface. The theoretical and experimental densities are used to calculate the density of the Al2618 alloy with B 4 C composites. By using rule of mixture the theoretical values are predicted and using the standard weight method experimental densities is calculated. The specimen is machined in accordance with ASTM standard E10 [21] for hardness testing. The Brinell hardness tester machine is used to test the hardness. The polished surface of the specimen is smooth. A 5 mm ball indentation is made on the sample, and a load of 250 kg is applied. The results of 5 indentations are noted on the surface of the specimen and tabulated. The specimens are machined in accordance with ASTM standard E8 [22] to investigate the tensile behavior of Al2618 alloy and Al2618 alloy with varying weight percentages of B 4 C composites. The Computerized UTM is used to test the tensile strength, investigate the behavior of Al2618 alloy reinforced hybrid composites subjected to unidirectional tension, and analyze the effect of uniform distribution. The specimen's overall length is 104 mm, 45 mm gauge length and a gauge dia., of 9 mm. This tensile test can be used to determine the mechanical behavior of as cast alloys and composites. Compression strength is calculated using the ASTM E9 standard [23]. Fig. 3 depicts the tensile test specimen.

Figure 3: Tensile test specimen.

Using a pin on disc wear machine, Al2618 alloy and Al2618 with B4C reinforced composites wear behavior are investigated. The tests are carried out as per ASTM G-99 standard [24] on specimens measuring 8 mm in dia., and 30 mm in length. After performing dry sliding wear experiments at varied loads of 10 N, 20 N, 30 N, and 40 N and at 2.09 m/s sliding velocity for 3000 m sliding separation, the wear was considered. Similarly, the dry sliding wear conduct of Al2618 compound composites was investigated at 40 N load and 3000 m sliding distance at varied sliding speeds of 0.52 m/s, 1.05 m/s, 1.57 m/s, and 2.09 m/s. The height loss misfortune was reported as a wear misfortune.

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