Stiffness is an indicator of the tendency for an element to return to its original form after being subjected to a force. Strength measures how much stress can be applied to an element before it deforms permanently or fractures. Hardening affects both as is demonstrated in the video the un heat treated material can be bent easily and it does no significantly return to its original shape, it is very mailable it bends but does not break. When heat treated it will not bend as easily and if enough force is applied it may actually break but the force required would be much greater. So it is both stiffer and stronger. Everything is a trade off.
Both the guys here are confusing stiffness with strength. Heat treating does not make a difference to stiffness (the distance a length of extrusion will deflect under a given load) but to strength (the amount of load which will cause the same item to develop a permanent bend)
Stiffness is an indicator of the tendency for an element to return to its original form after being subjected to a force. Strength measures how much stress can be applied to an element before it deforms permanently or fractures. Hardening affects both as is demonstrated in the video the un heat treated material can be bent easily and it does no significantly return to its original shape, it is very mailable it bends but does not break. When heat treated it will not bend as easily and if enough force is applied it may actually break but the force required would be much greater. So it is both stiffer and stronger. Everything is a trade off.
Both the guys here are confusing stiffness with strength. Heat treating does not make a difference to stiffness
(the distance a length of extrusion will deflect under a given load)
but to strength
(the amount of load which will cause the same item to develop a permanent bend)