Effect of input microwave power and insulation on microstructure and tensile properties of cast Al 7039 alloy produced at 2.45 GHz

Abstract

In the present work, microwave energy was used for casting Al 7039 alloy at 2.45 GHz in the ambient cavity environment. Effects of input power and insulation of the mould assembly during irradiation on charge melting and mould preheating were studied. Five different casts were produced at 1000 W, 1200 W, 1400 W, 1400 W with an insulated pouring basin and 1400 W with insulated mould assembly. Melting time of the charge was the least while using 1400 W with insulated mould assembly, whereas preheating of the mould was observed minimum during casting at 1400 W inside an insulated pouring basin. Cast microstructures revealed that less preheating of the mould resulted in finer grains and intermetallics, which improve tensile properties of the cast. Fractographic analyses showed the presence of coarse intermetallics in the casts produced with insulated mould assembly, which resulted in significant reduction of tensile properties.

Keywords:

• Microwave energy
• casting
• aluminum alloy
• microstructure
• tensile property

Disclosure statement

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

Additional information

Notes on contributors

Radha Raman Mishra

Radha Raman Mishra is an Assistant Professor of Mechanical Engineering at Birla Institute of Technology and Science Pilani, Pilani, India. He received his Ph. D. in Mechanical Engineering from Indian Institute of Technology Roorkee, Roorkee, India. Post-Ph. D., Dr. Mishra was involved in research and product development activities at the Design Innovation Center, Indian Institute of Technology Roorkee, Roorkee, India. His research interests include microwave processing of materials, microwave joining, microwave drilling, microwave casting, composites materials, additive manufacturing and product development.

Apurbba Kumar Sharma

Apurbba Kumar Sharma is currently a full Professor in the Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, India. Prof. Sharma is also Coordinator of the Design Innovation Center at the same Institute. He received his Ph. D. in Mechanical Engineering from Indian Institute of Technology Madras, Chennai, India. He has contributed various research articles, including a number of well-cited review articles, in reputed journals in the area of microwave processing of materials, surface engineering, and advanced machining processes apart from authoring invited chapters in the Handbooks. He has edited journal issue as guest editor and chaired a number of technical sessions in the international conferences. He is a member of many professional bodies. His prime research interests include microwave joining, microwave cladding, microwave drilling, in-situ microwave casting, micromachining, advanced manufacturing processes, hybrid finishing processes and wear characterisation.