| Abstract Scope |
High entropy alloy (HEA) concept was introduced in 2004, which may consist of five or more elements in near-equiatomic concentrations. The high-entropy effect was manifested in stabilizing single solid solution phases due to the high configurational entropy with an increasing number of elements. This concept inspired a rapidly growing trend in multi-principal element alloy (MPEA) fillers for joining of similar and dissimilar materials since 2014. A vast design space and expansive single-phase fields are compelling for filler development. Especially in the brazing processes, many existing fillers with melting-point depressants suffer embrittlement caused by intermetallic compounds formation. MPEA composition spaces can yield single-phase compositions with appropriate melting points while eliminate embrittling microconstituents. This presentation reviews the recent progress on MPEA fillers including substrate pairings that have been investigated, filler selection or design strategies, filler fabrication methods and challenges being faced, and discusses potential future directions of MPEA fillers. |