why does heat bend metal more easily?

Question

GCSE

Answer 1

Metals deform by the movement of defects known as disclocations. The more easily these move, the more easily deformation occurs. In order to move, a certain amount of energy is required. Heat provides additional energy for dislocation movement.

Normally upon bending, or plastic (permanent) deformation, dislocations build up, blocking other dislocations, making bending more difficult. This is known as work hardening. At high enough temperatures, this is negated because the metal will "recover" from these defects.

Answer 2

Heat doesn't bend the metal; applying force to the metal causes it to bend.

However, the atomic bonds holding the molecules together (in rigid formation) CAN be affected by the introduction (or removal) of energy ... like heat. As energy is added, the bonds loosen and the structure "softens", making it require less force to form into another shape. Conversely, removing energy tightens the bonds and makes the structure "harder" or "more brittle", thereby increasing the force necessary to change form.

Answer 3

Stiffness in a metal,which is its resistance to bending comes about due to its Moment of Inertia and Young's Modulus primarily when we study gross properties of metals. At the atomic level it is because of bonding between atoms. When we heat a metal, there is expansion and the mechanism of bonding breaks down to an extent and it is possible to bend a metal using probably 10% of force which other wise is required when it is cold.

Answer 4

Heat makes metals easy to bend because it anneals them. This causes dislocations in the crystal lattice to ease. The reason metals are strong is that as you try to bend them you create dislocations that run through the lattice - when these meet and existing dislocation they are blocked. Annealing removes this problem.

Heating does not significantly weaken bonds!

Answer 5

Hi >
Any good Blacksmith would know that the molecules of the metal are "jumping around"
It renders the material more pliable, as the internals of the substance move around more freely.
Put ice-cream in the micro-wave - same thing. It goes runny.
The bits can jump around and make more space.
It all gets "softer".Anything that goes very cold has less dynamics, anything really hot has bags of energy.
Like me.
"Just a joke"
Bob

Answer 6

Heat doesn't bend metal in isolation.

Answer 7

molecules when cold conserve energy and stay still, tight and solid, when heated gain energy so bounce around making the structure soften

Answer 8

because the heat causes the atoms to seperate and weakens their density.

Answer 9

expansion of solids when temp increases .