Informatics Publishing Limited

DEVARAJ S ¹, CHANDRA MOHAN H. K ², NARAYANA SWAMY K. S ³, RANGANATHA R ⁴

Affiliations
1 School of Mechanical Engineering, REVA University, Bengaluru 560064, IN
2 Department of Mechanical Engineering, SJC Institute of Technology, Post Box. No.20, B.B. Road, Chickballapur 562 101, IN
3 School of Mechanical Engineering, REVA University, Bengaluru 560064, IN
4 Department of Mechanical Engineering, SJC Institute of Technology, Chickballapur 562101, Karnataka, IN

Abstract

Cu-Al powder for different weight percentages of 5, 10 and 15 was ball milled for 30 min. The compacts of pure Cu, Cu5 wt.% Al, Cu-10 wt.% Al and Cu-15 wt.% Al was compacted using metallic die by applying 70 kN force. The compacts were kept in a heat treatment electrical resistance furnace at 600^oC for 8hr for conventional sintering. The conventional sintered compacts were tested to measure the behaviour of the alloy. The density of the sintered compact of Cu, Cu-5 wt.% Al, Cu-10 wt.% Al and Cu-15 wt.% Al were calculated using water displacement method. The surface topography of the sintered compacts were analysed using optical metallurgical microscope for the magnifications of 100x. The microstructure of the copper is exhibited cellular structure. The quantity of the secondary phase increases with increasing Al content. The hardness values of respective compacts were measured using Wilson micro Vickers hardness testing machine. The micro Vickers hardness values of Cu, Cu-5 wt.% Al, Cu-10 wt.% Al and Cu-15 wt. % Al were measured as 38.78 ± 1.2, 21.22 ± 2.0, 24.54 ± 3.7 and 39.44 ± 3.5 HV1 respectively. The compression strength of the sintered compacts of pure copper, copper with 5, 10 and 15 wt.% Al were determined using universal testing machine. The compression strength of Cu-15 wt.% Al is higher than copper and other sintered Cu-Al compacts.

Keywords

Conventional sintering, copper, aluminum, bronze, microstructure, mechanical characterization.

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Chandra Mohan H. K ¹, Devaraj S ², Narayana Swamy K. S ², Venkatesh B K ²

Affiliations
1 SJC Institute of Technology, Chickballapur 562 101, Karnataka, India., IN
2 REVA University, Bengaluru 560 064, Karnataka, India., IN

Abstract

Al-30 wt.% Si hypereutectic alloy was produced by die casting and spray forming technique. The microstructures, mechanical and tribological properties of the alloy were studied. The density of die cast and spray formed samples are measured using water displacement method by applying the Archimedes principle. The scanning electron micrographs of die cast and spray formed alloys revealed the morphological changes of silicon phase from coarse silicon needles to fine silicon needles due to high undercooling encountered in spray forming. The size of the hard silicon platelets are decreased from 22 µm to less than 10 µm as the processing method is changed from die casing to spray forming. The average Vickers micro hardness of die cast and spray formed alloy are 70.06±2.65 HV and 78.05±2.01 HV respectively. The respective yield strengths of die cast and spray formed alloy are 130±9MPa and 150 ±7 MPa and the compression strengths are 251±11.6 MPa and 283±6.32 MPa. The precipitation strengthening mechanism is found to be involved in spray formed alloy.

Keywords

Alloys, Mechanical Properties, Microstructure, Wear Properties.

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