Wear Behavior of Cooling Slope Rheocast A356 Al Alloy

Abstract

In the present study, the dry sliding wear behavior of rheocast A356 Al alloys, cast using a cooling slope, as well as gravity cast A356 Al alloy have been investigated at a low sliding speed of 1 ms⁻¹, against a hardened EN 31 disk at different loads. The wear mechanism involves microcutting–abrasion and adhesion at lower load for all of the alloys studied in the present work. On the other hand, at higher load, mainly adhesive wear along with oxide formation is observed for gravity cast A356 Al alloy and rheocast A356 Al alloy, cast using a 45° slope angle. Unlike other alloys, 60° slope rheocast A356 Al alloy is found to undergo mainly abrasive wear at higher load. Accordingly, the rheocast sample, cast using a 60° cooling slope, exhibits a remarkably lower wear rate at higher load compared to gravity cast and 45° slope rheocast samples. This is attributed to the dominance of abrasive wear at higher load in the case of rheocast A356 Al alloy cast using a 60° slope. The presence of finer and more spherical primary Al grain morphology is found to resist adhesive wear in case of 60° cooling slope processed rheocast alloy and thereby delay the transition of the wear regime from normal wear to severe wear.

KEY WORDS:

• Semisolid
• Cooling Slope
• Rheocast
• Spheroidal
• Abrasive Wear
• Adhesive Wear

ACKNOWLEDGEMENTS

The authors thank the Director, CSIR-CMERI, for his continuous encouragement and all of the members of the NNMT group for their support and personnel at the Central Research facility, CSIR-CMERI. The authors also want to convey their special thanks to Dr. Himadri Roy, Phani Kumar, and Tapan Ray, CSIR-CMERI, for their kind help toward successful completion of this research work.

FUNDING

The authors thank DST, New Delhi, for funding of this research work.