Manufacturing Technology Today

G. N. Lokesh ¹, S. Shivakumar ², K. V. Mahendra ³, S. Karunakara ¹

Affiliations
1 Dept of Mech Engg, Acharya Institute of Technology, Bengaluru, IN
2 Dept of Mech Engg, Sir M. Visvesvaraya Institute of Technology, Bengaluru, IN
3 Amruta Institute of Engg & Management Sciences, Ramanagara, IN

Abstract

In the present work the combined effects of particle size and distribution on the mechanical properties of the fly ash particle reinforced Al–Cu alloy composites is investigated. It has been shown that small ratio between matrix/reinforcement particles sizes resulted in more uniform distribution in the matrix. The particles distributed more uniformly in the matrix with increasing in mixing time. The results also showed that homogenous distribution of the fly ash particles resulted in higher hardness, ultimate tensile strength, yield strength and elongation. Fracture surface observations showed that the dominant fracture mechanism of the composites with small fly ash particle size (27μm) is ductile fracture of the matrix, accompanied by the “pull-out” of the particles from the matrix, while the dominant fracture mechanism of the composites with large fly ash particle size (77μm) is ductile fracture of the matrix, accompanied by the fly ash particle fracture.

Keywords

Powder Metallurgy, Fly Ash, Mechanical Properties, Particle Size.

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G. N. Lokesh ¹, S. Shivakumar ², S. Karunakara ³

Affiliations
1 Dept. of Mechanical Engineering, Presidency University, Itgalpura, Rajankunte, Yelahanka, Bengaluru, IN
2 Dept. of Mechanical Engineering, Sir M Visvesvaraya Institute of Technology, International Airport Road, Hunasamaranahalli, Yelahanka, Krishnadeveraya Nagar, Bengaluru, IN
3 Dept. of Mechanical Engineering, City Engineering College, Kanakapura Road, Doddakallasandra, Bikasipura, Bengaluru, IN

Abstract

In the present investigation, the Al-Cu matrix reinforced by B₄C particulate was fabricated using stir casting and squeeze casting technique. The stir cast composites so produced were subjected to hot rolling for 40% reduction and the composites have been evaluated based on the investigation of mechanical properties. The wear tests were carried out using a pin on disc technique. Microstructure of the composites was observed by scanning electron microscope (SEM). The results show that the hardness and tensile strength increases with increase in percentage of B₄C by stir casting squeeze casting and rolled composites. But squeeze casting composites shows higher strength than stir casting and rolled composites show higher mechanical properties than both stir and squeeze cast composites. The test results showed that rolled specimens fabricated by stir casting technique have greater wear resistance than those fabricated by squeeze casting technique. Microstructure shows better bonding between matrix particle interface and no fracture observed in rolled composites.

Keywords

B₄C, Stir Casting, Squeeze Casting, Hot Rolling, Wear.

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G. N. Lokesh ¹, S. Shivakumar ², S. Karunakara ³

Affiliations
1 Department of Mechanical Engineering, Presidency University, Rajanukunte, Yelahanka, Bangalore, Karnataka, IN
2 Department of Mechanical Engineering, Sir M Visvesvaraya Institute of Technology, Yelahanka, Bangalore, Karnataka, IN
3 Department of Mechanical Engineering, City Engineering College, Kanakpura road, Bangalore, Karnataka, IN

Abstract

The processing of metal matrix composites (MMCs) by casting process is a very promising way of manufacturing near net shape composites at relatively low cost. The liquid metallurgy stir, squeeze casting technique has the characteristics such as fine microstructure as a result of rapid cooling, low porosity and good bonding between the particles and base alloy. Hematite is a common iron oxide with a formula called Fe₂O₃ and has been widespread in rocks and soils. Hematite forms in the shape of crystals through the rhombohedral lattice system, and it has the same crystal structure as lmenite and corundum. The paper presents the results of experimental investigation on mechanical properties of Fe₂O₃ particle reinforced aluminium metal matrix composite. The influence of 3, 6, 9 and 12wt% Fe2O3-p reinforced on mechanical properties was examined and the outcome of the tests revealed that hematite particles can be successfully used as a reinforcement material and it does not deteriorate the properties. The increase in hematite particle percentage and high squeeze pressure resulted in high density of the compact, thereby increasing compression strength, tensile strength and hardness of the composite. The results also showed that for the same base alloy the squeeze cast shows higher hardness, tensile and compression strength compared to the gravity cast base alloy. Squeeze cast composites exhibit higher hardness tensile and compression properties by increasing weight percentage of reinforcements. The microphotographs of squeeze cast samples shows uniform dispersion of the reinforcements in MMCs with good bonding between the matrix and reinforcement.

Keywords

MMCs, Hematite, Stir and Squeeze Casting.

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