EFFECT OF INTERLAYER THICKNESS ON ALUMINA-STEEL BONDING THROUGH FRICTION WELDING

Y.C. Keg, & Z.A. Ahmad*

Abstract

EFFECT OF INTERLAYER THICKNESS ON ALUMINA-STEEL BONDING THROUGH FRICTION WELDING

Y.C. Keg¹, & Z.A. Ahmad².

¹Pusat Pengajian Sains, Kale] Universiti Teknologi Tun Hussein Onn, 86400 Batu Pahat, Johor

²School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang.

Although friction welding is a promising technique for joining ceramics to metals, the joining of steels to ceramic workpiece has not been extensively studied. In this study, steel rods 9 mm in diameter were friction bonded to alumina rods using 0.015 mm aluminum foil as an interlayer. Friction and forging pressures of 20 MPa and 40 MPa respectively were used while rotational speeds were maintained at 1250 rpm. Sheets of aluminum foil (64,256 and 320) were used in order to obtain different thicknesses of the resultant interlayer. Under optical and electron microscopy, incomplete bonding was observed at several points along the metal-interlayer-ceramic interface. The numbers of sheets used significantly affected the resultant thickness of the interlayer which varied from 0 to a maximum of 100 ,um. Under the electron microscope deformation of the aluminum foil was observed. Entrapped oxide layers were visible using back scattered electron imaging. Mechanical interlocking and close contact between the aluminum and the ceramic were observed at magnifications in excess of 500X. Microhardness indentations show that the hardness of the steel was not significantly different from the hardness of the parent steel material.

*Corresponding author: Tel. + 6 (04) 593 7788 ext. 6167 E-mail. zaky@kuittho.edu.my