Title: Influence of melt treatments and polished CVD diamond-coated insert on cutting force and surface integrity in turning of Al-12Si and Al-12Si-3Cu cast alloys

Authors: K.G. Basava Kumar, P.G. Mukunda, M. Chakraborty

Addresses: Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur-721302, India. ' Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur-721302, India. ' Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur-721302, India

Abstract: The microstructures, machinability and surface characteristics of Al-12Si and Al-12Si-3Cu cast alloys were studied after various melt treatments such as grain refinement and modification. Results indicate that combined grain refined and modified Al-12Si-3Cu alloys have microstructures consisting of uniformly distributed α-Al dendrites, eutectic Al-silicon and fine CuAl₂ particles in the interdendritic region. These alloys exhibited better machinability and surface characteristics in the cast condition compared with the same alloy subjected to only grain refinement or modification. Performances of the turning inserts (uncoated and polished CVD diamond-coated) were evaluated in machining Al-12Si and Al-12Si-3Cu cast alloys under dry environment using a lathe. The polished CVD diamond-coated insert outperformed the uncoated cutting insert, which suffered from sizeable edge buildup leading to higher cutting force and poor surface finish. The polished CVD diamond-coated insert shows a very small steady wear without flaking of the diamond film during cutting.

Keywords: grain refinement; modification; machining; Al-Si-Cu cast alloys; melt treatments and polished CVD inserts; cutting force; surface integrity; turning; diamond coatings; microstructure; machinability; surface finish; tool wear.

DOI: 10.1504/IJMR.2007.014639

International Journal of Manufacturing Research, 2007 Vol.2 No.2, pp.117 - 137

Published online: 21 Jul 2007 *

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