What is the difference between toughness and hardness? I came to know about some materials that have low toughness but high hardness such as ceramic tiles and glass.
I want to know if it is true that high toughness also implies high hardness.
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3Check these links - neither term implies the other. Hardness, Toughness – Nikhil Anand Jun 24 '20 at 10:59
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This may help. https://physics.stackexchange.com/q/102822/37364 – mmesser314 Jun 24 '20 at 12:49
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1Does this answer your question? Are hardness, strength and toughness of materials not the same thing in a way? – John Rennie Jun 24 '20 at 15:43
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Hardness is resistance to deformation by a sharp point. Toughness is the amount of energy absorbed during deformation (as the object is yielding), up to the point of fracture.
It's possible for a substance (like a diamond) to be extremely hard and at the same time exhibit low toughness- where it can be shattered to pieces with a single well-placed hammer blow. Substances that exhibit low toughness like this are referred to as brittle. In fact, for a substance to be tough, it must be able to significantly deform prior to breaking, which is impossible for brittle materials.
In a stress-strain graph, toughness is represented by the area under the curve of load versus deformation. Toughness therefore can be exhibited by a variety of combinations of resistance to deformation and elongation at fracture, where that curve ends. In this way, it is possible for something as soft as rubber to exhibit a remarkable level of toughness, but no chunk of rubber will ever be as tough as even an ordinary (and not very hard) chunk of steel.
Hardness, by the way, is measured by how deep the pit is that is created by pressing a standard indentor into the surface with a standard load.
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