Effect of Al Content on Fracture-Behavior Transition due to Strain-Rate Change in Fe-Si-Al Alloys

The effect of Al content on the fracture-behavior transition from brittle to ductile fracture due to strain-rate changes in various Fe-Si-Al (Si + Al = 4 wt%) alloys was studied. The fracture-behavior transition was investigated using tensile tests at a wide range of strain rates ranging from 10-3 to 103 s-1. For Fe-Si-Al alloys with low Al content, the tensile sample fractured in a brittle manner at high-strain rates. On the other hand, at low-strain rates, nominal stress-plastic strain curves represented both uniform and local elongations, and the specimen fractured in a ductile manner. The fracture-behavior transition due to strain-rate changes was observed in Fe-Si-Al alloys. The strain rate at which the fracture-behavior transition occurred in Fe-Si-Al alloys increased with increasing Al content, and the brittle fracture of Fe-Si (high Fe content) alloys could be successfully suppressed in the presence of Al.