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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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Aren't nearly all materials Phase Change Materials?

I was reading about use of parrafin in melting snow Linked from https://ceramics.org/ceramic-tech-today/paraffin-offers-superior-solution-to-road-salt-for-melting-snow-ice links to http://www....
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1answer
37 views

How to calculate the max load a metal bar can hold?

How would one calculate the amount of weight a steel bar could hold before breaking? Apologies for the terrible diagram. So if I had a steel bar of the length 18in, and the cross-section with a ...
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0answers
42 views

Is ironing clothes beneficial for fabric properties? [closed]

First of all, I looked into different StackExchange sites but I think this is the most suitable for the question given that there is no "materials" site (more suitable than Chemistry and Arts & ...
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0answers
4 views

Coupling Coefficient of Piezoelectric Material

How is Coupling Coefficient of Piezoelectric Crystal measured? I found in an old lab manual that coupling coefficient of Piezoelectric Crystal equals $\frac{1}{Q_M}$ where $Q_M$ is the quality factor ...
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5 views

Tourmaline-Laden Ceramics in Hair-Care Products

I have seen a great deal of hype for hair care products in which the ceramic of any part of the product (barrels of hairbrushes (particularly the cylindrical blowdrying brushes), heating elements of ...
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1answer
33 views

Definition of Brinell hardness

I'm trying to understand the concept of Brinell scale. In Brinell test, a steel ball is pressed against the material under examination and the diameter of the indentation left by the ball is measured. ...
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1answer
57 views

Why don't sand get deformed when someone walks on it?

My question is about the structure of sand. Namely, when we walk on the beach sand seems to be very hard to deform, since we push on it from 'above'. But if from another perspective it is also very ...
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0answers
35 views

Why does flame doesnot have a shadow? What is the actual reason behind this? [duplicate]

I have read somewhere that flames doesnot cast a shadow. What is the actual reason behind this even a flame is physical in nature and we can see it.
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2answers
76 views

If EM waves of radio range can pass through large obstacles, why antennas do receive them? [closed]

For example a tiny antenna in the phone, why em wave do not pass through it, but pass through concrete walls?
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0answers
21 views

How can I draw the energy bands for the first and second zones of Brillouin? Is it conductor or insulator?

I want to draw the energy ($E$) diagrams for a simple cubic cell of parameter $a$, where each atom provides two electrons for the almost free electron levels for planes [100], [110] and [111]. I ...
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1answer
18 views

How do multiple start screw threads have higher advance per revolution (lead)?

Single-start means that there is only one "ridge" wrapped around the cylinder of the screw's body. Each time that the screw's body rotates one turn (360°), it has advanced axially by the width of one ...
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17 views

Soft question about deposition through Spin Coating.

I'm working developing an experimental procedeure for depositing nano particles on glass substrates, and I have a soft, or really dumb question rather, to ask before I feel comfortable in proceeding ...
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21 views

How to obtain stress-strain curve from torque-angle of twist curve?

If a shaft, fixed at one end is acted on by a torque, shear strain and stress develops within the shaft. If we are in the linear region (hooke’s law applies), the stress and strain can be deduced by ...
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0answers
59 views

How to explain a strength of the sphere in simple terms?

In our high school's physics book (in Turkish), a strength of the material is discussed in simple terms given by Galileo: The strength of the material is proportional to its cross-section area divided ...
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1answer
51 views

Why human knowledge about small scale physics is growing much faster than knowledge about big scale phenomena? [closed]

According to Kardashev scale there are subzero types civilizations according to their expertise in small scale physics (e.g. nanotechnology), which are classified according to Wikipedia as: Type ...
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0answers
18 views

Stress-Strain behavior of ceramics at high temperatures

Can someone explain to me why do we observe the peak in the stress strain behavior at 1400 C and then a sudden decline followed by gradual increase? What does it signify? Does it have anything to do ...
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1answer
147 views

Points of symmetry in $k$-space

Can you relate a point in the reciprocal space with a vector in real space? How do I find the family of planes that represent a point of symmetry in the Brillouin zone? For example, germanium has ...
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0answers
22 views

How to estimate the mobility of atoms implanted in the interstitials and/or vacancies of a crystal?

I would like to compare the likelihood for implanted helium atoms to move from interstitials/vacancies of a crystal versus neon atoms. I read in the literature that He atoms located in interstitials/...
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1answer
13 views

Why do the concepts representative volume element and characteristic scale come apart?

Does every characteristic scale have an associated representative volume element? Are they unrelated concepts?
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2answers
72 views

Is thermal conductivity correlated with speed of sound in metals?

Right off the bat I should say: thermal conductivity and electrical conductivity are definitely correlated in metals. image source: https://www.doitpoms.ac.uk/tlplib/thermal_electrical/printall.php ...
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0answers
33 views

How does hardening / tempering steel affect it's stress-strain curve?

Does hardening / tempering steel only scale it's stress-strain diagram horizontally (meaning it takes more strain to achieve the same stress) or does it also change the shape of the diagram (for ...
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1answer
35 views

Young's modulus and shear modulus relation - temperature effect

Young's modulus and shear modulus are related by $E=2G(1+\nu)$ (for isotropic and homogeneous materials), $E$ is Young's modulus, $G$ is shear modulus and $\nu$ is Poisson's ratio. I can do experiment ...
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2answers
114 views

How to calculate the time to uniformly heat an object by natural convection?

I want to heat a piece of steel (~40 kg) in a muffle until I bring it to a uniform temperature. The idea is to preheat the muffle to a certain temperature and then place the piece in it and wait for ...
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1answer
41 views

Hooke's Law and Overstretched Springs

Recently been working with Hooke's Law at university. My experience of real springs tells me that stretching to a certain point causes the spring to lose "springiness". (Not sure if "elasticity" is ...
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0answers
21 views

Estimating the maximum frequency of waves on a fixed string?

I would like to understand if/how I can estimate an upper limit on the frequency of (standing) waves that can be generated on a string fixed at both ends. As a first step, the properties of the ...
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2answers
67 views

Terminology for how bendable an object is and what affects the bendable-ness of an object

I was wondering what the term is for how bendable an object is. Also, does this feature vary depending on the thickness of the object? Say, for example, I want to know how bendable a ruler is. Does ...
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1answer
40 views

Is it possible to have an optical version of a greenhouse? With optical fibers?

Optical fibers transport light within them using internal reflection, but the light only enters from one end of the fiber. Is it possible to somehow have light entering from the sides of the fiber (...
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2answers
97 views

Is there such a material that only emits, or “sends out” the same color light that was “taken in” (absorbed)?

For example, glow-in-the-dark materials (photoluminescent) only emit a green hue regardless of the color of the light shone on the material. Is there such a material that emits the color of the light ...
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1answer
44 views

What defines the color of objects? [duplicate]

Its the wavelength of the reflected light that gives us the perception of color? But how is this possible while we know also that electrons emit the absorbed photons? so we get 1 color from the ...
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1answer
35 views

von Mises yield criterion when all 3 principal stresses are equal and in tension

Based on the von Mises yield criterion, a material begins to yield at a point when the state of stress at that point is such that the scalar known as the von Mises stress, exceeds the yield strength ...
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1answer
64 views

How to find ultimate stress given true stress - true strain relation?

I am given the following problem: Consider a brass whose true (plastic) stress-true (plastic) strain is given by: $$\sigma_{T,p} = 530 \ \rm{MP}\times(\epsilon_{T,p})^{0.36}$$ To simplify the ...
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0answers
8 views

Wavelength importance in Pulsed Laser Deposition (PLD)

I found that in most ceases of complex oxide/cuprate deposition, used PLD has laser wavelength $\lambda$=248 nm. Is it any special reason to have this wavelength in order to make ablation of this ...
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1answer
65 views

Why doesn't a metre cube of common salt weigh 2170 kg if the density of NaCl lattice is 2170 kg/m^3?

Why doesn't a metre cube of box containing common salt weigh $2170\ kg$ if the density of NaCl lattice is $2170\ kg/m^3$? As Mass = Volume x Density then for a unit volume shouldn't Mass= 1 x 2170= ...
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1answer
76 views

Debye Temperature for Copper

I am trying to calculate the Debye temperature, $\theta_D$, of copper using the following: $$ \theta_D = \frac{\hbar v_s}{k_B} \left( \frac{6\pi^2N}{V} \right)^{1/3} $$ I have the following values: $...
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1answer
192 views

Using the Debye model, show that the contribution of the zero point energy to the lattice vibrational energy is given by $𝑈=(9/8)𝑁𝑘_B𝜃_𝐷$

Using the Debye model, show that the contribution of the zero point energy to the lattice vibrational energy is given by $𝑈={9\over8}𝑁𝑘_B𝜃_𝐷$. I know that The zero point energy is $E={1\over2}\...
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0answers
20 views

Using Miller indices to determine interference from a particular plane in a crystal lattice

In terms of x-ray diffraction from crystals. I was wondering how you can use the miller indices to determine whether there will be constructive or destructive interference from a particular plane in ...
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0answers
21 views

What values or equations do I look up to find the energy dissipated of a sound wave through a specific material?

Generally when a sound passes through a massive object, many of the higher frequencies get cut off and the volume of the sound that passes through has been partially dampened. I'm sure the magnitude ...
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0answers
18 views

Is there any epoxy/sealant that is optically clear and can withstand temp up to 400C? [duplicate]

Any polyimides-type or any glue that can tolerate that temp AND be able to transmit visible light not uner 80% transmission?
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4answers
73 views

Possible to have a string that can bend but not twist?

I am looking for a string that can bend and flex easily but not twist. I want it to be able to snake through pipes, around bends, but not allow rotation of the thing at the end of the string. The ...
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0answers
43 views

Physical limits of multiplying the elasticity tensor of a material by an arbitrary constant

Can all the elements in the elasticity tensor $(C_{ijkl})$ be multiplied by the same, positive constant (say $\lambda$)? If so, what are the physical limits? I've done some research myself and ...
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0answers
44 views

First Brillouin zone for a centered rectangular network

The Wigner-Seitz cell is a primitive cell constructed from planes that bisect the lines connecting a chosen point to the neighboring network points. The cell of Wigner-Seitz in the reciprocal space is ...
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1answer
72 views

Which material has the highest diamagnetism? [closed]

I know that graphite and bismuth have the strongest diamagnetism, but between the two, which one is stronger?
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2answers
43 views

Why does the strength of a sheet of material under strain increase with thickness?

For instance, why is a thick plywood table able to bear heavier loads than a thin plywood table? I am aware of the concept of tensile strength but, seeing as that only says things about the strength ...
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3answers
78 views

Ray sun heating

I recently got a curious question about the sun rays. Is there a material that can absorbs most of them and turn it into pure heat? For example, we all know that dark material (black t-shirts) get ...
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2answers
78 views

Why do we use wool for insulation? [closed]

I'm really struggling to understand the science behind wool, and why it's a good insulator. I'm doing an investigation about heat transfer, and the topic I chose is insulators.
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5answers
21k views

Why does paper cut through things so well?

Paper is an extremely flexible material, at least when it is in sheet form. It will deform significantly according to the pressure applied and it is easy to fold. Therefore, it's extremely ...
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0answers
41 views

Issues with Miller indices

I have read that to find the intercepts of a plane represented by Miller indices is to take the reciprocal of each index. However, I noticed that does not give the original plane if we had to reduce ...
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1answer
117 views

Can I uncut a piece of paper?

I've inadvertently cut a piece of paper that I wasn't meant to. I've repaired it pretty well using single sided sticky tape and I think, so long as no-one looks at it too closely, I'll get away with ...
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1answer
43 views

Cast metal vs. machined metal

Why is it, that machined metals, milled out of a primitive shape, tend to bend upon impact rather than crack or shatter? Why do they behave differently to stresses when they are cast into the final ...
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0answers
15 views

How severe is the damage of surface contamination on Quartz Glass?

During a vacuum PVD (Physical Vapour Deposition) process I use tubular resistive heaters with a Quartz Glass shell around it (around 1.5m long) to heat up my organic material. During the process my ...