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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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What exactly is a 2DTI phase?

I am reading a paper about the electronic properties of quantum heterostructures and it mentions that "the material can be tuned into a 2DTI phase". I am clueless as to what that means.
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1answer
48 views

What would you call shelves failing after being bumped by a forklift?

From the video in this question, you can see a bunch of stable shelves that are bumped by a forklift. This causes a domino effect, but unlike a regular domino falling over, there is clearly a buckling ...
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11 views

Spraying aluminium hydroxide nanoparticles onto PLA as fire retardant? [migrated]

Several scientific papers study FR-PLA (fire resistant PLA) in which Aluminium Hydroxide nanoparticles are melt blended into the PLA (example source: Advances in Flame Retardant Poly(Lactic Acid). ...
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7 views

Is positive and negative magnetostriction attributed to the shape of the domains?

I have been reading up on magnetostriction, and noted that some materials expand while other contract in the direction of an applied magnetic field, and that it is attributed to the rotation of the ...
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14 views

How does acoustic impedance change with frequency of the wave and thickness of the medium?

I read in many posts that the acoustic impedance of a material is usually defined as Z = p*c, where "p" is the density of the material under consideration and "c" is the speed of sound in that ...
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1answer
40 views

Wood: A Naturally Occurring Composite Material?

In materials science texts, I see wood used an example of a naturally occurring composite material. One of the main components of wood is cellulose, which is a polymer. But what other component makes ...
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8 views

Semiconductors with low thermal conductivity (lattice matched to GaAs)

What are the semiconductors with lowest thermal conductivity that can be grown on GaAs with the least possible incorporated strain (i.e. lattice-matched or close to it)? GaAs has thermal conductivity ...
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2answers
36 views

Why is the mechanical energy lost whenever an object undergoes plastic deformation?

I have read here that "Mechanical energy is lost whenever an object undergoes plastic deformation." Why is that? I mean the object would be changing its shape, and while it's changing its shape it ...
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1answer
26 views

What does increase in weight of the sample on heating imply?

I have done TGA(Thermogravemetric analysis) of the sample and the result of the same shows that the % weight has increased for increase in certain range of temperature.Generally, the weight decreases ...
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81 views

What is a ferroelectric metal?

I was reading online about ferroelectricity, and came upon the topic of ferroelectricity in metals. The main cited paper is the one below by Anderson and Blount in the 1960's Symmetry Considerations ...
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1answer
38 views

What creates a negative charge in the material?

What creates a negative charge in the material? Is it an electron or a holon? Holons as I understand is a math. But what then creates an electrostatic repulsion? Is it still electron?
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36 views

Why bicycles' rims are bent after winter? [closed]

I've noticed that the rims of many bicycles which are parked in the street during the whole winter are heavily bent. I'm wondering what causes this deformation? Typically, this happens to rather cheap ...
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1answer
21 views

Do materials gain compressive or tensile strength if compressed?

If I take a block of play-dough and squish it down, it becomes harder to pull apart and push together. Does this same phenomena hold for "real world" materials? If I take a block of steel and ...
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1answer
29 views

Rare earth doping in ferrites [closed]

I have seen many papers where rare earth have been doped in ferrites . What are the properties that are changed by doing so?
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0answers
34 views

Is compressive strain equal to streching strain?

The stress induced on a piece of material (like a rectangular beam) is defined as: $$\sigma = E\epsilon$$ where $E$ is the elastic modulus and $\epsilon$ is the strain. The strain on the other hand ...
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30 views

When does a steel cable snap?

We have a woven cable made up out a large number of thin single strings of steel. Let's make the assumption the strings don't get deformed. Now the strings are not all equally thick, so let's make the ...
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3answers
96 views

Hooke's full unapproximated law

It is known that the Hooke's law relating the restoring force of a spring to the distance of retraction from the equilibrium position, is only an approximation. That is, the equation $F=-kx$ is only ...
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1answer
52 views

Minimal quantity of substance to reveal its physical state properties

What is minimal quantity of matter required to reveal its physical state properties? I.e. number of particles/atoms when their collection can be considered as liquid, solid, gas or plasma. I am aware ...
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3answers
52 views

Confusion Regarding Hookes law

I am used to seeing Hookes law in the form: $F = kx$ but in another one of my books it gives the equation: $\\ F = \frac{\lambda x}{l}$ where $l$ is the unstretched length, $x$ is the extension and $\...
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1answer
26 views

How to determine whether an alloy is single or multi phase

I would like to know what methods would be suitable to determine if an alloy of 2 elements is a single phase or two phase alloy.
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11answers
7k views

Are there physical properties that can be used to differentiate stainless steel from copper in a home environment? [closed]

So the backstory is that I purchased a reusable drinking straw that is copper coloured, but is advertised to be stainless steel. That got me thinking about whether I could be sure it was one or the ...
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0answers
20 views

Is this a simple fracture mechanics model

If I use the interatomic potential $V(x_i-x_j)= \frac{1}{2}k(x_i-x_j-a)^2$ for $|x_i-x_j-a|<b$ $V(x_i-x_j) = V_0$ for $|x_i-x_j-a|\geq b$ for the critical displacement $b$ and Equilibrium ...
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10 views

Viscosity table or diagram for melts of oxides

Is there a table or diagram to relatively determine which oxides have low 'melt-viscosity' (i.e relatively flow readily when melted)? Is it possible to determine such property based on phase diagrams ...
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40 views

What is the difference between metallicity and semimetallicity?

I am looking for a definition of semimetallicity from an experimental point of view ( $\rho(T)$, carrier density, mean free path, scattering time, etc.) and from a theoretical point of view. Can ...
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0answers
23 views

How are fluid membranes stretchable?

The Poisson's ratio of fluid lipid membranes is exactly $\nu=0.5$, because fluids can flow. As answered in this question, under the assumption of a finite bulk modulus $K$, this is the value of $\nu$ ...
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1answer
67 views

How much harder is a proton theoretically speaking than a diamond? [closed]

It's generally said that a diamond is the hardest substance known to man (apparently there are a few materials known to be harder). However, one ought to expect that a proton or neutron should be ...
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0answers
26 views

How can I beforehand determine whether a material is a good candidate for a microwave sensor?

Is there a table of some sort or formula where I can determine before I test the material under a microwave sensor whether it will allow the microwaves to pass through and if so at what depth. for ...
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0answers
13 views

What is plasmonic trapping?

I am going through a research paper (DOI: 10.1039/c4fd00224e).I could not understand what plasmonic trapping is in it. Can you make it clear for a beginner in Plasmonics ?
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42 views

Are 2D materials really two dimensional?

I am learning more about 2D materials. Does anyone have any reference, literature, videos, lecuters for basics? Main question for start is that why called 2d? Because even if it one layer of atom, it ...
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0answers
14 views

How does a super current affect ductility, maleability and the mechanical properties of a superconductor?

In metals, the ductility, malleability, tensile strength and strain are all determined in part by their free electrons. I am wondering what would happen to all of these properties of a superconductor ...
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0answers
11 views

Derive Porosity from Stiffness Value

I have the Young's modulus (stiffness) values of a hydro-gel scaffolds, and I need to know the porosity of those scaffolds. I read about Nielsen Equation, which is this: $$ E = \frac{E_0 (1 - P) ^ 2}...
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0answers
18 views

How are the orientations and cuts of crystal substrates determined?

I have been looking at piezoelectric crystals, LiNbO3 primarily, so piezoelectric devices. But I have had trouble understanding the cuts and orientations that are referred to with the rotated cuts. ...
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1answer
39 views

Material with discontinous conductivity

Is there a material whose thermal conductivity can be modeled by the function $$k(T) = \begin{cases}k_1, & T<T_0 \\ k_2, & T\geq T_0\end{cases}$$ where $k_1$, $k_2$ are constants. I ...
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2answers
76 views

Why don't insulators conduct electricity? [closed]

I have been taught in school that because of the high energy band gap (approx. $9~\text{eV}$ or more) of an insulator, electrons can't jump to the conduction band. But also $1~\text{eV} = 1.6 \cdot ...
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0answers
26 views

Stable bubbles in a vacuum

I want to make space bubbles that hold some gaseous stuff - at very low pressure - for a long time and through nothing but surface tension. I can't use soap water as the water will evaporate quickly. ...
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1answer
64 views

Is there a theoretical upper limit for how hard something can be? Harder than diamonds?

Is there a theoretical upper limit for how hard something can be under "normal circumstances" (i.e., on the surface of Earth or similar or in the empty space)? Something like absolute zero/infinity on ...
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1answer
34 views

Is a solid slab of rolled steel the strongest form? [closed]

Is a solid slab of rolled steel its strongest form? Or can it be made stronger, in another form (layered, foam, mesh, braided etc)? (Its weight is not a factor, and no alloys/additives) Also, ...
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1answer
22 views

Determine whether a body breaks due to mechanical stress

How to determine if a body breaks if I know ultimate tensile stress of that body, other mechanical properties of the material and Cauchy stress tensor applied to the body? It is simple if only one ...
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1answer
38 views

What limits how hot can a macroscopic object be heated by conventional means?

What I mean by conventional, is that chemical, mechanical and electromagnetic heating are in bounds, but not nuclear. And I assume that there a limit to how much a material can be heated due to: The ...
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0answers
46 views

Why are diamonds formed under high pressure? (use entropy)

My book asks how can diamond ever be more stable than graphite, when it has less entropy. I have to explain how at high pressures the conversion of graphite to diamond can increase the total entropy ...
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0answers
22 views

Teflon (PTFE) against another teflon [closed]

Would teflon sleeve spinning againts teflon bushing create so much friction that it would just break? I have a teflon bushing spinning againts metal sleeve, and it is the original design, which works. ...
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2answers
49 views

which give higher cooling rate , strong circulated water or thick copper plate? [duplicate]

imagine if I have hot metal piece I want to cool it as fast as possiple, should I put it in strong circulated water bath or just stick it between 2 thick copper plates ? the calculated heat ...
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1answer
23 views

which is more effective chilling for metal casting, thick copper die or water-cooled thin copper mold? [closed]

It is will known that increasing cooling of a metal casting will lead to finer micro-structure which mean higher mechanical properties. If I have 2 molds one is thick copper die ,& second is just ...
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1answer
153 views

Relation between Young's modulus and density?

Can I calculate Young's modulus from density? Is there any mathematical relation between Young's modulus and density?
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1answer
41 views

Hollow cylinder pressure tolerance [closed]

I have a physics\material science problem. We have a hollow cylinder with length L, inner diameter d and outer D made of a material with known mechanical properties(whatever constants are needed). ...
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2answers
73 views

How to calculate materials ability to resist penetration

I would like to ask you this question which I struggle to answer. If I have a plate of some material X to which I am shooting at with a tank main gun with ammunition parameters: weight $= 10\text{kg}...
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0answers
45 views

How can a single particle hit many pixels in Large Hadron Collider?

In the Large Hadron Collider, the way particles are detected (specifically in ATLAS) is analogous to detecting photons using a photodiode(analogous is an exaggeration, but will suffice for the ...
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2answers
36 views

How to determine at which temperature does iron in stainless steel undergoes spontaneous oxidation?

It is my understanding that iron oxidation in stainless steel is prevented by adding chromium, which creates chromium oxides at the surface that shield the bulk of the material from further oxidation. ...
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0answers
21 views

Can a pressure wave travel faster than a material breaks?

Consider a shock wave travels through a solid (M) which causes a 4g acceleration. Down below there is an elastic spring (K1) which suppose to support the mass in case K2 will fail. K2 is a rigid body ...
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3answers
29 views

What is the sound absorbing characteristic of a material called?

I understand that lead is one of the best acoustic barriers because it absorbs sound very well; in other words, it converts sound to heat. By comparison, other materials tend to either transmit the ...