This is an EPSRC supported project (EP/D00313X/1), which is to study the feasibility of fabricating a MEMS component by embossing using ultra-fine grained (UFG) aluminium alloys. The current study is the first attempt to produce metallic foils with features at the scale of 5–50 μm by embossing using UFG aluminium alloys produced by ECAP.
A novel process for fabrication of a microelectromechanical systems (MEMS) metallic component with features smaller than 10 μm and high thermal conductivity was investigated. This may be applied to new or improved microscale components, such as (micro-) heat exchangers.
In the first stage of processing, equal channel angular pressing (ECAP) was employed to refine the grain size of commercial purity aluminium (Al-1050) to the ultrafine-grained (UFG) material. Embossing was conducted using a micro silicon mould fabricated by deep reactive ion etching (DRIE). Both cold embossing and hot embossing were performed on the coarse-grained and UFG Al-1050. Cold embossing on UFG Al-1050 led to a partially transferred pattern from the micro silicon mould. Hot embossing on UFG Al-1050 provided a smooth embossed surface with a fully transferred pattern.
The behaviour of Al alloys during the embossing process was analysed using finite element modelling. This study shows a good potential for fabrication of microdevices by embossing UFG alloys processed by ECAP.
