Questions tagged [material-science]

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19 views

Problem with relationship between shunt resistance and grain boundaries in a solar cell

Here is the correct answer from another stack website: electronics.stackexchange.com/a/570917/288858 The higher shunt resistance means that higher the polycrystalline lattice irregularity and many ...
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1answer
34 views

At what length does my spaceship snap on landing?

I'm planning some fiction involving a very long spaceship landing. Initially I wanted the ship to be the same length as the NEC railroad, at 750 km. However looking at the mathematics of the situation,...
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44 views

Why do solar cells need to be square-shaped?

There were circular solar cells 30 years ago. Why do we have square-shaped solar cells now? Why square? Furthermore, Why do monocrystalline solar cells have rounded/cropped edges?
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17 views

Why is it more convenient to express stress tensor in Material rather than Spatial coordinates?

I was reading chapter introduction about Stress and the author wrote the following about stress tensors: "Since the current configuration of many problems, especially those involving solids, is ...
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18 views

Heat treatment processes in Nickel-Based Superalloys?

What is the difference in heat treatment process between Wrought Ni-Based superalloys &cast Ni-Based superalloys
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2answers
46 views

Heat Deflection VS Coefficient of Thermal Expansion?

I was looking at a spec sheet for a photopolymer and saw these two different subsections under the "Thermal" section. I tried Googling around as I usually do, but no site could give me the ...
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1answer
22 views

Rubber that remains Elastic in Hot and Dry Application

I work for a valve manufacturing company and our customers have an application where very large volumes of hot (200F), dry air pass through our valve. As a consequence, the rubber (carboxylated ...
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3answers
37 views

Equivalent sheet metal thickness of different alloys

I want to replace steel plates that are being used as trim tabs on a boat with 90-10 cupronickel. The main design parameter is to make sure the plate has no less flex than the part being replaced. In ...
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1answer
50 views

Stress strain curve stress and resilience

When calculating 0.2% offset from stress strain curve please, do I take 0.2% of the original length and then, divide this by original length to get strain and plot this please? And for resilience, is ...
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1answer
52 views

How to find yield strength and Young Modulus from S-S curve

I have a S-S curve and am not sure how to find yield strength from it as when I did 0.2% strain (0.002 * strain at fracture) I get a small number that plots close to (0,0)? For young modulus, I am not ...
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1answer
37 views

What does time temperature specifically give us? [closed]

What is a Time Temperature curve basically? I have come across this a couple of times while dealing with heat treatment in my industry. A detailed reply to this is most welcome.
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22 views

What impact does reduction internal stress cause?

I have noted that recovery primarily reduces the internal stresses of the material.What is particularly confusing is why would that work out.A slightly detailed answer to this is most recommended.Also ...
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2answers
3k views

Why doesn't epoxy stick to silicone?

Why doesn't epoxy stick to silicone? Is there a type of epoxy that does?
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17 views

Alternative materials for reflectors in solar concentrating systems

Other than the usual silvered mirrors, that are expensive to form into parabolas, what can be used as an effective reflector in parabolic troughs/dishes. I saw a few people tried using Mylar and Al-...
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1answer
38 views

Why does decrease in dislocation density result in higher ductility?

Why does a decrease in dislocation density result in decrease in yield strength and increase in ductility?A slightly detailed explanation is what I am looking forward to.
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1answer
21 views

Relevancy of (neutron energy loss and atomic weight) and the material selection of fast and thermal nuclear reactor

From this https://www.nuclear-power.net/glossary/neutron-moderatoraverage-logarithmic-energy-decrement/, I have found that the relationship between atomic weight and neutron energy loss can give the ...
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1answer
32 views

Mirror specification used in Solar Fresnel Collector systems

Im designing a Linear Fresnel collector system, and wanted to know what type of mirrors would be suitable for use as the reflectors. Thickness, type, coating etc. I couldnt find a manufacturer of ''...
1
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1answer
177 views

How do the constraints imposed on a material increase the stiffness?

As the title of this post says, how do the contraints increase the stiffness. For example, I was doing an exercise where I had to calculate the deflection on a rubber block with and without deflection ...
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1answer
19 views

Injection moulding

What are some examples of real polymer products that can be be produced by injection moulding ? I thought plastic bottles may be one but I think that is done mainly using injection blow moulding
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1answer
30 views

can simply beating cast material with a hammer inside a mold improve it's strength

I asked my materials science proffesor if forging a cast part (inside a mold to prevent shape change) can increase it's strength to that of a forged part. She told me to find out myself and tell the ...
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1answer
37 views

Polymer based disc brakes

I know that you can have metallic and ceramic composite brakes. My question is can you have disc brakes for a car that consists of polymetric materials or would this be impossible due to its low melt ...
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0answers
27 views

Burrs on the wire surface after drawing

I have been involved in wire drawing for some years now. But only recently, I noticed that the wire surface was uneven and had burrs when inspected under a microscope (see photos). The wire is a Ni-Fe ...
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1answer
46 views

Why carbon ceramic brakes

What key physical, chemical and mechanical properties of carbon ceramic brakes make it better compared to other brakes for example metallic brakes made of cast iron ? I know that they are much more ...
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1answer
55 views

Salt grinder and corrosion

I am looking for a kitchen salt grinder. I know salt is an aggressive compound and it needs a little bit of attention when we design products. Since most of grinders have plastic-made or stainless ...
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0answers
12 views

why did my ceramic matrix composite turn out brittle as snow?

I have attempted making a ceramic matrix composite (cmc) by wetting glass fiber cloth with waterglass and baking it at 200°C. The resulting material disintegrated on touch. Unwetted fibers did not ...
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1answer
10 views

Is there a name for a process of constructing gradient/smoothly distributed material density?

Are there conventional processes by which one can construct a material that gradually transitions from one alloy or molecular density to another? For instance if I wanted a material that gradually ...
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1answer
32 views

Question about a particular statement on plastic deformation of single crystals

"...the wider the dislocation, the lower is the elastic energy of the crystal because the atomic spacing in the slip direction is closer to its equilibrium spacing." What has elastic energy ...
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0answers
30 views

Doubt in triaxial stress state in a notched specimen

In the book titled "Mechanical Metallurgy" written by G.E.Dieter I am having problems to understand why a notch in a material would mean a triaxial state of stress.I do well understand that ...
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2answers
512 views

Why does corrosion take place at certain stressed regions?

Why does certain parts of metal show more corrosion at the place where there is high dislocation density in comparison to the place where the dislocation density is less? I do sincerely feel that this ...
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1answer
689 views

Is it possible to determine how the steel was made, having its microstructure (for example, to distinguish forging from rolled products)?

How do you think the steel in these images was made? Example1 (https://i.stack.imgur.com/oZLRM.jpg) Example 2 (https://i.stack.imgur.com/jrDE7.jpg) Example 3 (https://i.stack.imgur.com/fpl2d.jpg) ...
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1answer
28 views

What Rubber is Best for Laser Cut McKibbens PAMs?

I'm a layman engineer who's decided to take another step forward in my research and work with McKibbens Pneumatic Artificial Muscles. I’m new to creating custom rubber components and laser cutting, so ...
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0answers
15 views

How to judge the character and sign of a dislocation?

I do understand that $ \mathbf b||\mathbf t$ for screw dislocation but I am unable to judge the sign of the dislocation. Again if $\mathbf b \perp \mathbf t$ how do I judge its sign? Any formula which ...
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0answers
14 views

Difference in the properties arising from precipitates and intermettallics

What are the key differences in the mechanical properties caused by precipitates and intermettallics in metal alloys? So far I've found that intermettallics are larger phases, and are usually hard and ...
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2answers
37 views

How effective are screen protectors?

Screen protectors are supposed to protect your devices from nicks and scratches, as well as the stress of impacts which might otherwise lead to cracks or shattering. The fundamental principle behind ...
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0answers
15 views

Readily available PVC plasticizer

I'm looking for products that can be used as non-toxic PVC plasticizers. I've used ATBC as a product that I can add to, for example, the inside of a pool toy, which with time absorbs it and becomes ...
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0answers
10 views

Would outside reinforcement increase thermal shock resistance of a glass cyllinder?

Would a glass cyllinder reinforced on the outside with tensioned glass fiber be more resistant to thermal shock than an unreinforced one? I understand that the failure happens when the glass starts to ...
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0answers
57 views

Finding fraction of liquid and solid from isomorphous alloy phase diagram

if alpha of 82% B and liquid of 57% B are in equilibrium in an alloy of 73% B,the fraction of liquid is? I know formula for it, but confused in finding property. Any help will be of great use & ...
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2answers
81 views

Machinability index for ferrous and nonferrous material [closed]

What are the machinability index for ferrous and non-ferrous materials? Please help me so that I can learn more about it. Thanks
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0answers
14 views

Verifying MERV Integrity for Specified Material

This is a question related to materials science. Essentially I want to purchase MERV 16 material from a manufacturer and I want to verify that it's true MERV 16 material when I receive the order. ...
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0answers
14 views

Is there any ecological modifier which can be added to PLA to make it not brittle, and good for some heavier-duty outdoor food-grade use?

Is there any modifier which can be added to PLA to make it not brittle, and good for some heavier-duty outdoor food-grade use? The criteria is that adding the modifier still keeps the material ...
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1answer
93 views

How to estimate the tensile strength of inch diameter steel round?

The tensile strength for 1045 TGP Precision Steel Round is said to be 91 ksi. Although, different diameters must be a factor, right? Would a 1" diameter rod be 104.5 ksi or 1045 ksi? Say I want ...
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1answer
16 views

Is there a way to visualize or quantify atomic clusters in crystalline materials?

For multi-component crystalline materials, can we detect atomic clusters containing just 2, 3, or 4 atoms? Take a material $A_4B_3C$ for example. Can we detect clusters of A with 2 atoms (pairs), 3 ...
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1answer
20 views

How many kind of material resistance are there in engineering?

I have seen many kind of material resistance mentioned scattering around, such as fracture resistance / deformation resistance / chemical resistance / weathering resistance and so on But I cannot find ...
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1answer
112 views

How is linear motion achieved in this automatic blackboard eraser?

In the animation shown below what can be the mechanism used for this purpose? I know it can be achieved by using rack and pnion gear arrangement. But how are this set up arranged in classroom ...
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4answers
4k views

Why are most jigsaw blades designed to cut on the up stroke and have teeth that point towards the shank?

Why are most jigsaw blades designed to cut on the up stroke with teeth that point towards the shank? Why are reverse teeth jigsaw blades less popular?
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2answers
173 views

How does a pressure vessel fail when the interal pressure exceeds the yield stress of the material?

When we design a pipe or pressure vessel, we look at hoop stress and longitudinal stress and then look at the material properties. We assume that the material reacts to the load as a solid. However ...
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3answers
97 views

Beginners material science for handling a load

I’ve got a reasonably strong grasp of Newtonian mechanics, but as far as material science goes I don’t know which of the many material properties I need to use to solve my problem: I’m trying to mount ...
2
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1answer
49 views

I have a small piece of stainless steel that I need to remove 1-2mm of material. The hardness is 200. What type of file do I need to get?

This is a part of a mounting system for an Olight pistol flashlight. The universal adapter that they include isn't so universal when it comes to a Canik handgun. I've talked to the people at Olight ...
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1answer
246 views

Hansel-Spittel equation parameter determination

I am currently learning how to determine the Hansel-Spittel equation parameters. The equation has following form: $$\sigma= A \cdot e^{m_1\cdot T}\cdot(\epsilon^{m_2})\cdot \exp\left(\frac{m_4}{\...
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1answer
43 views

What is the relationship between the strain in different directions?

A cube made of an isotropic material is subjected to a tensile stress as shown in Figure 2. What is the relationship between the strain in different directions ? There is an elongation in $z$ ...