Smaller is Stronger
Science has long known that at the nano-scale, materials get stronger. Take a sheet of nickel for instance: you can bend it with little force; but a nano-sized piece of nickel would require far more force to deform. Although this has been well known for sometime, what hasn't been known is why that happens. Until now.
Materials deform because of existing defects in the planes of the materials crystalline structure. As force is applied to a macro-sized material, these defects increases, colliding with each other and multiple. In effect, with the right amount of force, you can cause a runaway increase in defects in a material, which results in deformation. In nano-scale materials however, the opposite happens. As force is applied, defects in the material dissipate in a process called mechanical annealing. In effect, as force is applied to nano-scale materials, the material becomes stronger, as defects disappear. (With enough force however, defects return and rapidly increase, resulting in deformation -- but that's a lot more force than it would take to deform a macro-scale material.)
Ain't that cool?
Materials deform because of existing defects in the planes of the materials crystalline structure. As force is applied to a macro-sized material, these defects increases, colliding with each other and multiple. In effect, with the right amount of force, you can cause a runaway increase in defects in a material, which results in deformation. In nano-scale materials however, the opposite happens. As force is applied, defects in the material dissipate in a process called mechanical annealing. In effect, as force is applied to nano-scale materials, the material becomes stronger, as defects disappear. (With enough force however, defects return and rapidly increase, resulting in deformation -- but that's a lot more force than it would take to deform a macro-scale material.)
Ain't that cool?
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