Development of diffusion bonded materials for electronics cooling applications

Atabay, Sıla Ece
Failure of most of the electronic systems are originating from deterioration of the components due to excessive heat flux generation. The unstoppable demand for more complex and miniaturized electronic systems makes the development of more suitable and feasible production methods for their cooling systems and components compulsory. In the scope of this study diffusion bonding behavior of the aluminum (Al) 6063 alloy was investigated to make this bonding method and alloy system available for the electronic cooling systems. In diffusion bonding every parameter has an important effect on the properties of the resulting joints. These effects were investigated in this study to determine the optimum bonding parameters in terms of the resulting mechanical properties of the joints. Consequently, maximum bond shear strength was achieved under 13 MPa pressure at 520C for three hours when the bonded samples were cooled in air. Preserving the physical and chemical properties of the base metal is essential along with obtaining high bond strengths for the formation of a solid joint. To minimize the degradation in the properties of the alloy without altering the composition, silver, nickel and gold interlayers were applied to the bond interface. However, interlayer addition was proven to be unsuccessful in terms of bond formation. Rather than using an interlayer, addition of copper (Cu) and tin (Sn) as alloying elements to the Al 6063 was also studied to examine their effect on the properties of both the base metal and diffusion bonded joints. Cu alloying was found to be preventing the loss in the mechanical properties of the base metal without causing any increase in the bond strength. On the other hand, enhancement of joint formation was observed in the Sn containing alloys along with a slight decrease in the strength of the base metal.