Manufacturing Technology Today

N. Vijaya Sai ¹, M. Komaraiah ², A. V. Sita Rama Raju ³

Affiliations
1 Dept. of Mechanical Engg., V. R. Siddhartha Engg. College, Vijayawada, IN
2 Malla Reddy College of Engg. & Technology, Secunderabad, IN
3 Dept. of Mechanical Engg., J.N.T.U. College of Engg., Hyderabad, IN

Abstract

Copper matrix composites containing 0-16 wt% fly ash with or with out copper coating were prepared using powder metallurgy. The copper coating of fly ash particles was carried out using an electroless process. Small cylindrical specimens were fabricated at 300 MPa using single action die compaction at ambient temperature. These compacts were sintered in argon atmosphere for a period of 45 min at 850, 890, and 930° C, respectively. The density, porosity, hardness, compressive yield strength and wear resistance of the sintered compacts were determined as a function of fly ash weight percent. Density and compressive yield strength of the composites were found to decrease with increasing weight percent of fly ash. The addition of fly ash resulted in increase in porosity and hardness of both coated and uncoated fly ash composites. The wear resistance of coated and uncoated composites was found to increase up to 8 wt% fly ash addition, beyond which a marginal decrease is observed. Coated fly ash composites possessed better combination of density, porosity, hardness, yield strength and wear resistance than uncoated composites. At high volume fractions, the use of copper coated fly ash was found to yield superior composites than the use of a mixture of uncoated fly ash and copper powder.

Keywords

Copper, Composites, Compressive Yield Strength, Density, Electroless Coating, Fly Ash, Hardness, Porosity, Wear Resistance.

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P. Kishore Kumar ¹, N. Vijaya Sai ², A. Gopala Krishna ³, N. G. Renganathan ⁴

Affiliations
1 Dept. of Mech Engineering, Veltech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Chennai, Tamilnadu, IN
2 Dept. of Mech Engineering, V R Siddhartha Engineering College, Viayawada, Andhra Pradesh, IN
3 Dept. of Mech Engineering, Jawaharlal Nehru Technological University, Kakinada, Andhra Pradesh, IN
4 Dept. of Chemistry, Veltech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Chennai, Tamilnadu, IN

Abstract

Austenitic stainless steels play vital role in high temperature applications. The components used in fission reactors should have better tensile properties at high temperature. To overcome the issues raised by conventional steels, a new group of steels known as oxide dispersion strengthened (ODS) steels are created. Nowadays, two groups of ODS steels such as the ferritic and austenitic ODS steels are being used. The present work mainly focusses on the processing of ODS austenitic steels. The consolidation processes adopted for ODS austenitic steels are discussed in detail. The microstructural features and precipitation of nano-oxides during compaction are also reported. In addition to this, the mechanical properties such as tensile strength and elongation values obtained by various manufacturing processes are also discussed.

Keywords

Oxide Dispersion Strengthened, Austenitic Steel, Consolidation, Nano-Oxides, Tensile Strength and Elongation.

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