arnisador said:
What's the distinction between 'harder' and 'tougher' here?
Though I'm by far no expert on swords, I have some knowledge of metallurgy.
Hardness is a characteristic that falls under the category of Durability, along with wear resistance and fatigue strength.
Toughness is a category unto itself consisting of sub properties, such as impact strength and notch sensitivity,
(Taken from
Engineering Materials: Properties and Selection Seventh Edition by Budinski, Kenneth G. and Budinski Michael K.)
So in relation to one another, in terms of mechanical properties, a sword that is extremely hard, would be incredibly durable (as in it would hold its edge well) but it would have a low level of toughness as its hardness would cause it have a low impact strength. And vice a versa, a sword that has a high impact strength would have a low durability.
Again, I am no expert on swords, but this is how it applies directly to materials and their mechanical properties. No alloy other than steel (steel is an alloy by the way) has the properties of steel, which is why it has yet to be replaced in many applications, including the manufacture of blades.
Just my $.02
-Josh