What is the major drawback in nanocrystalline alloys? a) - high brittleness b) - low hardness c) - rapid grain growth upon heating d) - low thermal conductivity

Answer: a) High brittleness

Explanation: Nano crystalline alloys are the alloys that have the packing of nano crystal that is the size of the crystal is very minute or small. The size of the nano crystalline alloys usually ranges around 100 nm. Due to such arrangement of the crystal the nano crystalline alloy becomes hard in nature and because of this property it becomes difficult to make them ductile. Therefore the major drawback in nano crystalline alloys are that it has high brittleness or hardness.