3.3.4 Examining the parts
Brittle fractures were discovered quickly in the mass of debris hauled from the river. Such samples became the focus of increasing effort as time went by, simply because they were unexpected. So the possible failure mechanisms were immediately narrowed down when brittle fractures of critical components started to emerge from the river.
Suggest what mechanisms could cause brittle fracture of steel components that might normally be expected to fail in a ductile manner.
There are several possible mechanisms that can cause brittle behaviour in any nominally ductile material such as steel:
excessively low temperatures, below the steel's ductile-to-brittle transition temperature;
severe stress concentrations;
stress corrosion cracking (SCC);
any combination of these mechanisms.