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What is the tailhook that enable naval aircraft to land on aircraft carriers, it must be made out of a strong metal to not bend or 'snap' under the force of the thrust that the plane is expelling, as they land then put thrust to full.

enter image description here

Image Source—PACIFIC OCEAN (Dec. 22, 2011) Landing signal officers supervise the arrested recovery of an F/A-18C Hornet on the flight deck aboard the Nimitz-class aircraft carrier USS Carl Vinson (CVN 70).

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    $\begingroup$ Looking at the specs, it is steel. Looking at the price, it must be unobtainium. $\endgroup$ – Peter Kämpf Oct 7 '16 at 15:00
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    $\begingroup$ You may also refer the Wikimedia image, there is a description with it. $\endgroup$ – mins Oct 7 '16 at 15:45
  • $\begingroup$ @PeterKämpf out of morbid curiosity, how much do they cost? $\endgroup$ – Jules Oct 7 '16 at 19:23
  • $\begingroup$ Remember that the cable they are hooking onto can help to gradually take the strain. $\endgroup$ – gecko Oct 7 '16 at 19:53
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    $\begingroup$ @gecko More accurately, the engine they're connected to. $\endgroup$ – Steve Oct 9 '16 at 15:57
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They're made of alloy steels that have ultra-high strength, high fracture toughness, excellent fatigue resistance, and high resistance to stress corrosion cracking.

Based on one of the manufacturers—QuesTek—the steel's grade is AMS 6516.

The 6xxx grade is a chromium-vanadium steel:

Chromium-vanadium steel refers to steel alloys incorporating carbon, manganese, phosphorus, sulfur, silicon, chromium, and vanadium. Some forms can be used as high-speed steel. Chromium and vanadium both make the steel more hardenable. Chromium also helps resist abrasion, oxidation, and corrosion. Chromium and carbon can both improve elasticity.

Elasticity is important because you wouldn't want a deformable tailhook.

Other applications for it are:

Landing gear, rotorshafts, driveshafts, arresting tailhooks and hookshanks, actuators, armor, munitions, gun barrels, and blast-resistant or impact containment devices.

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    $\begingroup$ I think you are confusing elasticity (amount of elastic/reversible deformation under a given load) with ductility (ability to deform plastically/irreversibly without breaking, i.e. the opposite of brittle). Other than that, fine answer - it's a common misconception that all steels are approximately the same, while low-end and high-end differ by an order of magnitude. $\endgroup$ – Sanchises Oct 7 '16 at 15:41
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    $\begingroup$ Not really. Elasticity is a material property 'if all is well' - it determines the stiffness of a structure. Plasticity (either ductility, malleability or brittleness -generalised as toughness) is failure behaviour: what happens after the ultimate strength of a material is reached. Will it bend, or will it snap? So, stiffness, strength and toughness are all different properties of materials, and should all be maximised (although they're usually a trade-off). As for your (dictionary) source, I do not know what they mean with 'increased elasticity' - a higher Young's or more elastic-like. $\endgroup$ – Sanchises Oct 7 '16 at 16:12
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    $\begingroup$ Yeah I may have overdone that a little - perhaps that's better reserved for metallurgy 101. I would just concentrate on the 'high strength' from the wiki's source - that's the most important thing anyway. $\endgroup$ – Sanchises Oct 7 '16 at 16:29
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    $\begingroup$ I can check after the weekend. I don't feel like scouring the internet for tables I can easily find in books. $\endgroup$ – Sanchises Oct 7 '16 at 19:35
  • $\begingroup$ Do you know how many landings the landing gears are rated to take before being replaced on average? $\endgroup$ – David Grinberg Oct 7 '16 at 19:56

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