“…It is known that at the elevated temperature, various intermetallic phases are formed as a result of interdiffusion between Au and Al: Al 2 Au, AlAu, AlAu 2 , Al 2 Au 5 , and AlAu 4 . Al 2 Au 5 was found to be initially a predominant phase at 733 K close to our annealing temperature of 773 K. However, it was reported that unstable Al 2 Au 5 rapidly transformed into AlAu 4 at a lower temperature of 673 K . In this work, Al 2 Au 5 , which would form at our annealing temperature, might be transformed into AlAu 4 during cooling.…”