One of the things I'm working on for my science fiction setting are reasons for laser weapons to not be very prominent.

One of the ideas I came up with was for the primary hull plating of most ships to made from fictional alloys that become increasingly reflective to thermal energy as it heats up. Yes, the laser will eventually melt it, but the majority of the energy is deflected (or reflected depending on angle) as it gets closer to that melting point.

What I want to know is, what other behaviors would such alloys likely have? Or are there any real world materials with similar properties I can use as a reference to such a trait?

Would this unique property have any effect on its viability as an armor against kinetic and explosive weapons?

I'm also imagining this alloy will be difficult to re-melt after its formed the first time.

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    $\begingroup$ It's a fictional material, you decide which properties should it have $\endgroup$ – L.Dutch - Reinstate Monica Jun 13 '18 at 16:16
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    $\begingroup$ Why do they have to become more reflective and are not just as reflective as possible to begin with? $\endgroup$ – Raditz_35 Jun 13 '18 at 16:17
  • $\begingroup$ It would not be enough to just reflect but to redirect. $\endgroup$ – Muze the good Troll. Jun 13 '18 at 16:23
  • $\begingroup$ I'm just trying to find out of there are other behaviors that a metal alloy might have that is directly tied to that specific behavior. $\endgroup$ – Arvex Jun 13 '18 at 16:31

To also address Raditz_'s objection ("why wouldn't the alloy be as reflective as possible from the start?"), what you want is exactly a partial melt of the alloy, to address reflectivity losses during the normal (non-battle) lifetime of the hull.

More to the point you need a composite material made up of different layers:

  • outer layer: low-temperature melting, ultra-low-vapour-pressure alloy (I'm thinking GalInStan or better yet Rose's metal due to its low expansion factor).
  • middle layer: high-temperature superconductor layer
  • inner layer: structural hull.

During normal operation, the starship's surface gets abraded by cosmic dust, hydrogen ions, solar winds and whatever. As a result, the surface is matted, opaque and microscopically roughed -- and would readily absorb laser energy.

Before a battle, or periodically, the hull is heated enough to melt the outer skin (less than 400 K are needed and you can zone-melt the hull to save energy). If necessary, replenishment liquid metal is then poured on the hull to make good for losses. Cooling in vacuum, the hull becomes a perfectly reflective mirror (99%+ reflectivity), allowing deflection of incoming laser radiation.

When hit by a laser, a part of the hull will vaporize and briefly flare in a gaseous cloud, which will reflect most of the incoming beam (this is one of the great limits when engaging targets in an atmosphere).

The hull can be melted and more metal added even during an attack, and most of the heat from the laser would be transferred to the superconductor and radiated harmlessly in space. You would need sufficient laser power to fry the whole starship if you wanted to inflict damage.

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  • $\begingroup$ That was part of the reason. The other reason being that this setting is for a game and ships that are shiny don't really fit the art direction I've been going in. $\endgroup$ – Arvex Jun 13 '18 at 17:02
  • $\begingroup$ Well, nothing prevents the metal to be a dull grey when solid. This would mean the ship would need some minutes to melt the skin before engaging battle, and remain in molten state throughout. $\endgroup$ – LSerni Jun 13 '18 at 17:03

The problem with that is when atom moves faster they reflect lasers less but certain metals hold there reflection better at higher temperatures like chrome. The metal that best reflects is platinum unless you get into Dielectric mirrors which use layers with thicknesses of the order of a light wavelength to allow interference effects can achieve 99.999% reflection but at very limited wavelengths for a given mirror.

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