Evaluation of alloys for thermal interface contact and for additive manufacturing

Abstract

The present purpose aims to investigate research gaps identified in two important sectors of industry. Firstly, solidification of Sn-Bi(-In) solder alloys must be examined in copper substrates. In this case, the focus will be at the formed interfaces as a result of either solidification or localized reactions at the interface. This project will propose techniques in order to optimize the microstructure and application properties such as mechanical and corrosion resistances. These properties are crucial for thermal interfaces applied for heat dissipation. These materials are termed as TIM (Thermal Interface Materials). Pb-free TIM alloys such as Sn-Bi based ones are required nowadays due to the need of electronic devices having higher processing capabilities. The result is the need of increase heat release, i.e., more efficient and reliable TIM alloys. With this in mind, various factors must be accomplished, that is: wettability, thickness and nature of the reaction layers, Cu dissolution and microstructures. Secondly, determination of inter-relations type microstructure à processing parameters à properties remains essential for aluminium alloys with potential application in additive manufacturing (AM). For most of the alloys of interest (i.e., Al-10%Si-Mg-(Sc, Ni) and Al-5%Mg(-Sc) alloys), fundamental solidification parameters in order to control the process remain undetermined. One of the major contributions of this project will be establishing process maps so that connection between microstructure and parameters/properties could be established. Various techniques will be applied, which are: wettability (in the case of TIM alloys), corrosion, tensile and hardness tests. The characterization of intermetallic particles formed during solidification of the alloys of interest is also a concern which will be explored in this work. Intermetallics formed either at the interfaces of the Sn-Bi(-In)/substrate couples or those constituting the bulk multicomponent Al alloys will be assessed. Both thermodynamic computations and advanced microscopy will be employed in this regard. Efforts on examining the effects of Sc during age hardening of the AM alloys will be also focused on. (AU)