Questions tagged [material-science]

The study of how the properties of matter arise from its structure at all scales and of how processing can be used to modify those properties (often in pursuit of a specific application).

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1answer
15 views

Relation between ultimate stress and strain

I'm comparing the material properties of two polymers A and B and noticed that A has a lower stress at break, but a higher strain at break. Is it generally true of most polymer materials that when it ...
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19 views

Why is Material Toughness Ability to Absorb Energy Before Fracture?

Toughness is defined as ability of material to absorb energy when deforming before fracture. Materials with high ductility and strength will have high toughness. What is meant by ability of material ...
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Why Five independent slip system is required for plasticity to occur at macroscopic level?

According to von-mises criteria, we often encounter that five independent slip system is required for plasticity to occur at macroscopic level. Can somebody give an explain briefly about this proof or ...
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23 views

How does light water prevent criticality of natural uranium even as it is outside the zirconium cladding?

The main reason heavy water is used to allow nuclear reactors to operate with nuclear reactor is that they do not absorb neutrons, allowing an increase in neutron temperature that lets the few U-238 ...
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How would the thickness of the electrode affect the resistance of the circuit

Imagine a portion of the circuit is completed by gluing two electrodes on the opposite walls of the inside of a rectangular tube and submerge the tube in salt water, would the thickness of the ...
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4answers
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Why do little chips break off so easily from strong neodymium magnets?

I have some strong toy neodymium magnets. Typically after a while little chips start breaking off, unlike from most other small metal objects, like in this image. It could of course be that neodymium ...
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I need .cif file of Ca3Co4O9 and Ca9Co12O28 for Rietveld Refinement [closed]

I am looking for .cif file of Ca3Co4O9 and Ca9Co12O28 for structural refinement.
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How to predict the mechanical and metallurgical properties of an alloy by its composition? [closed]

An alloy is a composition of metals under a specific condition, how can we predict its properties?
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What dimensions would a quantum confinement system have to be for its electromagnetic emission spectrum to be in the radio section?

Just as specific dimensional restrictions on systems that have quantum confinement like quantum dots lead to the tenability of the emission spectrum of such a system, I was wondering how this idea ...
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1answer
55 views

What causes this pattern in wood knots [closed]

I am see these interesting looking lobes emanating out of knots of wood: The shape almost looks like magnetic field lines. It's probably just coincidence but I wonder if there is a similar PDE that ...
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1answer
35 views

How to convert anisotropic thermal expansion coefficients to an overall linear thermal expansion coefficient? [closed]

I am trying to compare thermal expansion coefficients of materials found in several articles. However, some report anisotropic coefficients and others report overall linear or volumetric (3*α linear) ...
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Is there any alloy that has the same oxidation resistance at high temperature?

Iridium is a rare and expensive metal, for those reasons and others I was wondering if there an alternative to it.
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Preventing parasitics for wires?

This is in relation to my question One-way magnetic shielding? where the correct answer gives some links to the material. My question is, does this material, one-way magnetic/electric shielding ...
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Drift velocity vs acceleration due to an electric field

So my understanding is that when you have electrons moving in a vacuum (like in an electron gun), applying an electric field across it will accelerate the electrons across the gap. Electrons moving ...
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Compression resistance in variable complex structures: connecting discrete titration data to (semi-)continuous data [closed]

Last year, I did several experiments on seeds, essentially testing the compressive resistance of different types. I had two different tests for this, neither of which could be done in a lab with ...
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1answer
55 views

Is there a relativistic theoretical upper limit to tensile strength per unit density?

When considering structures that support mainly themselves with tensile strength (e.g. space elevators and rotating space habitats like rotating wheel space station, Stanford torus and O'Neill ...
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What product results from pyrolysis of hydrocarbons and their deposition in non-planar surfaces?

Pyrolytic carbon forms from the thermal decomposition of hydrocarbons, which the results depositing and crystallizing unto a planar surface. However, what intrigues me is what would result in the same ...
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Does molten potassium wet steel?

I'm designing a device that uses molten potassium in steel pipes. If the device cools, the potassium will solidify and shrink, and if it's adhered strongly to the pipes I'm worried they may crack, so ...
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How to generate a complete set of doped (substituted) structures?

I'm trying to analyse doping in a certain material in low concentrations. I'm approaching the problem by taking crystallographic unit cell of that material, then expanding that to a 2x2x2 supercell ...
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2answers
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Is burned aluminium moka-pot safe to use? [closed]

The other day, we forgot a Moka Pot on the stove (maybe for 15 or 20 mins) and it got "burned" as in the pics attached. The Moka pot is made of aluminium, and my modest physics and chemistry ...
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Can a material have high permittivity and low permeability or the other way around?

Since the electric and the magnetic fields are interrelated, can a material have high permittivity and low permeability or the other way around? Would it be possible to have a material that would be ...
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1answer
40 views

Is sublimation of the metal filament in a vacuum tube the main reason for eventual failure?

I saw a question asking if metals sublimate, with some fascinating answers, which made me wonder if sublimation was the main cause of the eventual, and inevitable failure of vacuum tubes. High school ...
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4answers
60 views

Physics behind breaking [closed]

A very simple query. Suppose a box rests on a frictionless table. It has a max. normal force of $100 N$, say. Suppose I exert a force of $150 N$, which I suppose is not possible, since normal force by ...
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26 views

Relationship between extinction coefficient and the imaginary refraction index

I'm trying to add an ITO glass material made by SPI to an FDTD Lumerical simulation. For that I need the real and imaginary parts of the refractive index. In their website though, they give the real ...
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What is meant by structural hierarchy in microstructures?

I found one explanation for this, and one figure; but this tell me very little. Does anyone have an explanation in layman terms, if possible? "The hierarchical microstructures can be defined as ...
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Can electron-degenerate copper be produced in the lab?

The pressure needed for copper to reach it’s electron degeneracy pressure is 40 GPa, while pressure’s above 100 GPa can be produced with a diamond anvil. As such, have such copper samples being ...
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Is there a solid insulator at room temperature that has a dielectric strength slightly less than that of air?

Ideally the material retains its properties after it breaks down with high voltage.
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211 views

What does the notation $H{\parallel}ab$ mean?

In a research paper (Phys. Rev. B 84, 052507 (2011)), I have found the notation $H{\parallel} ab$, where $H$ is an applied magnetic field. In this context $a,b,c$ are the lattice vectors. What does ...
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What made aerogel so insulating?

In many science videos, it is shown that aerogel can insulate an extremely high temperature even though it is very fragile, what properties of aerogel made it so capable of insulating heat?
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What wavelengths of light does a banana reflect?

I do know that there are at least two types of yellow light: a light of a single wavelength of ~580 nm and a combination of green light and red light. (Technically, there could be more yellow light.) ...
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If a bar was from a geostationary satellite to the ground, would it stay stationary?

Suppose there is a perfectly geostationary satellite in orbit, and the satellite deploys a bar or a metal rod from the satellite to the ground, straight down(This is impossible, but hypothetically, it ...
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39 views

Would a macroscopic sphere with the thicknesss of a few atoms behave as an artificial atom?

As quantum dots are composed of closely packed atoms, where their electronic levels are bound and in a confined system, would a similar system, with the same thickness as a quantum dot but much larger ...
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1answer
21 views

How does a materials modulus of elasticity (proportional zone ratio) relate to crystal defects?

I'm studying biomedical engineering and I'm about to take "Biomaterials" (basically materials science applied to medicine) final exam. In one recorded class, the professor mentions the ...
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2answers
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What's the minimum possible size of a round astronomical body?

What's the minimum possible size of a spherical shaped rocky planet or satellite? Is it possible to occur a spherical shaped planet without having a molten core?
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Why are polycrystalline solar cells shinier than monocrystalline solar cells?

Being shiny reduces the efficiency of the solar cells. Additional to the grain boundaries that polycrystalline solar cells have that gives resistance to the current flowing in them, they are shinier ...
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3answers
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von Mises yield criterion on 'pure' shear

I want to predict when a particular sample will yield using the von Mises yield criterion, which in 2D reduces to: $$ \frac{1}{\sqrt{2}} \sqrt{(\sigma_{11}- \sigma_{22})^2 + (\sigma_{22})^2 + (\sigma_{...
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Is silicon a semiconductor or insulator?

I have read that pure crystalline silicon is an insulator because it has a such covalent bond that very tight and no free electrons available for conduction bands. They all are bonded with other ...
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How to maintain moisture on a substrate?

I know that different materials absorb water differently and dry differently. The simplest example is when washing clothes and putting them in the dryer they take different amounts of time to ...
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What materials are used in Difference-frequency generation optics?

There seem to be an abundance of materials when it comes to harmonic generation of photons but the information is rather lacking for this domain.
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Can EM (radio) wave oscillation interact with an antenna without photon absorption?

EM wave interaction with an antenna has been covered, e.g.: How do we visualise antenna reception of individual radiowave photons building up to a resonant AC current on the antenna? Most answers ...
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1answer
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What would be the most UV resistant rubber color?

I'm looking for the longest lasting speargun bands. They come in a variety of colors so I'm wondering if a certain color of rubber would help them last longer. They will be exposed to a lot of ...
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How to calculate wall thickness based on force and compressive strength

I’m reading Randall Munroe’s (xkcd’s) book How To, which outlines several fun ways to think about everyday tasks using physics. One chapter is titled How To Have a Pool Party and in it, he outlines ...
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Isothermal Gruneisen parameter for Germanium?

If phonon density of states peak shifts are purely quasiharmonic, we have $\omega$(V(T)). If phonon density of states peak shifts shifts are purely anharmonic, we have $\omega$(T). Does anyone know if ...
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Can the synchronous Larmor precession of several nuclei cause the emergence of a quasiparticle system?

As phonon's form due to the synchronous oscillation of their vibrational modes, couldn't the same apply to the synchronous oscillation of a system of protons oscillating at their fundamental frequency?...
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Is there an equivalent Larmor precession that is non-magnetic in nature?

Can the magnetic moment of a particle be manipulated without magnetic fields? Could one accomplish this with electromagnetic radiation or even "Atom Lasers"?
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1answer
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At what speed does a magnetic field form from the flow of current?

When an electrical current flows through a conductor and produces a magnetic field, does the magnetic field in the conductor form at the drift speed of the electrons in its structure or the velocity ...
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How would physics explain why I can't un-fold paper? [duplicate]

This seems like a silly question, but I would love to see a serious answer. It's known that almost all fundamental laws of physics are time-reversible, and time-asymmetry only comes about when we ...
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Why is the unloading curve on a stress strain graph usually shown as linear

In many examples given in textbooks & on the internet, with the exception of some materials such as rubber with their hysteresis loop, the unloading curve is linear. But surely there would always ...
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Would the effects of applying a phosphate surface coating to a nitrided carbon steel surface be desireable?

Question is pretty much in title- I have a nitrided carbon steel part that's surrounded by many bare steel parts- ideally I would be able to phosphate the whole assembly, but I have no idea if that ...
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Can paint on a wall considered to be a thin film?

In know that general thin films are as thin as few microns to nanometres and have technical and optical uses. But can a dry paint on wall be considered the simplest example of thin films? I mean its a ...

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