Effect of boron carbide and Kaoline reinforcements on the microstructural and mechanical characteristics of aluminium hybrid metal matrix composite fabricated through powder metallurgy technique

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ABSTRACT

In the present work Al- 10% B₄C- X% Kaoline (X = 0, 2, 4, 6, 8) hybrid metal matrix composite (HMMC) was fabricated through powder metallurgy technique. Physical and mechanical properties like density, Hardness, Porosity, Ultimate tensile strength (U.T.S) and Impact energy were studied for the fabricated composite samples. Results concluded that there was a 91.93% increment in hardness and 75% increment in U.T.S of the fabricated samples was observed for Al-10%B₄C-4%Kaoline HMMC. However, incorporation of kaoline reinforcement beyond 4% leads to the formation of agglomerates in the composites reducing the U.T.S from 238 MPa to 186 MPa and hardness from 119 VHN to 101 VHN. The fabricated composite specimens were characterised using an X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The XRD patterns reveal the presence of Aluminium, B₄C and kaoline particles. In addition to this, the presence of intermetallic phases was observed for Al-10%B₄C-6% Kaoline and Al-10%B₄C-8% kaoline HMMC. Uniform distribution of reinforcements and formation of agglomerations for 6% and 8% kaoline reinforcements was confirmed by SEM and their respective EDS mapping. Results showed that the Al-10 % B₄C- 4% Kaoline has superior mechanical properties compared to monolithic aluminium

KEYWORDS:

• Powder metallurgy
• Boron carbide
• Kaoline
• Hybrid MMC; Mechanical properties

Acknowledgments

The authors like to thank Central Instrumentation Facility at the National Institute of Technology Silchar for XRD analysis. The authors also would like to appreciate the Advance Centre for Material Science at the Indian Institute of Technology Kanpur for SEM and EDS analysis. The authors also acknowledge the aid and facilities provided by the CTTC Bhubaneswar for fabricating Punch and die setup for tensile and Hardness testing.

Disclosure statement

No potential conflict of interest was reported by the author(s).