Abstract:
Dissimilar micro-friction stir welding (dissimilar μFSW) can be a preferred choice for joining dissimilar materials
having thickness ≤ 1000 μm. The technique's potential applications are in miniaturized components, where the
inherent benefits of the process, such as low temperature, low distortion, and clean joining, are advantageous
compared to fusion welding. However, the challenges associated with dissimilar μFSW hinder its full potential
applications in the relevant industries. The challenges are particularly a combination of two different characteristics of the process (i) the complexities of simultaneously fulfilling the dissimilar materials' demands due to
the vast differences in the two materials' mechanical and thermal properties and (ii) the problems due to reduced
sheet thickness. In this regard, the present work is a comprehensive and timely review of the research works done
on dissimilar μFSW targeted at easily acquainting the research community about the know-how and the state of
the art of the process. The review is broadly divided into three crucial parts: the process inputs/requisites,
process mechanics, and process performance. The details about the μFSW tool, process parameters, and relative
sheet positioning are discussed under the heading process inputs/requisites. Concerning the process mechanics,
the intermetallic compound formation, defect generation, and material mixing are discussed. The joints' resulting
performance is shown by detailing the essential properties such as formability, residual stresses, fatigue, hardness, and tensile strength. Additionally, several future research directions are presented at the end of this critical
review to motivate further improvements in this joining technique and instigate its utility in relevant industries.
