Questions tagged [material-science]

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22 views

Is there a cloth-fabric that hardens on impact?

I am researching if there is a cloth/fiber (that can be worn) that instantly hardens on impact? I am well aware of oobleck - but this is a liquid. I also know of D30, which is a material that hardens ...
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18 views

Compressive load of a cylinder with holes along the length [closed]

I am trying to find the compressive load of a Q235A steel cylinder with a length of 248 mm, ID of 59mm, and an OD of 64 mm. The cylinder has holes along the entire length that are 18 mm apart. I know ...
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1answer
16 views

Is it possible to estimate the young's modulus of an aluminum alloy purely based off its alloy designation?

I recently had an interview where the interviewer asked what the young's modulus would be like for an alloy like 5052 versus 6061. was a bit stumped on this one, saying that 5052 might be lower ...
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3answers
37 views

Difference between fast or slow rising force on materials' breaking strength

Assume that force is applied to a material like a rope, steel cable or a beam until it tears apart. Does it make any difference for the breaking point if the force rises slowly or really fast?
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3answers
123 views

Does hitting an obstacle hard enough to break it actually reduce self harm?

Lets say that Car-A hits barrier that is fixed to immovable posts on either side of the road. The car's momentum is such that the barrier absorbs the impact and the car comes to a near instantaneous ...
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0answers
25 views

What tools are used to design and 'program' shape-memory polymers?

I've been reading about shape-memory polymers. However, it is not clear to me what tools could be used to design the ultimate shape (the shape one obtains after applying for example electricity or ...
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2answers
72 views

How does shear/viscous stress change in liquids as applied shear force is changed?

As per Newton's law of viscosity, the dynamic viscosity of a Newtonian fluid is constant (doesn't change with applied shear stress).Consider the Couette flow used to explain viscosity . Whenever we ...
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2answers
56 views

What is meant by Material Toughness being the 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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133 views

How do I EXACTLY calculate the k-factor for metal bending?

Introduction I've recently started to work with metals and the process of bending them. There is a lot more math involved than I initially thought. All the break press operators just have a ...
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3answers
90 views

Can we say that stress strain curve for a tensile test is function of strain rate and temperature?

I am currently studying about tensile test where it is saying that it is conducted at a constant strain rate. Also, it is said that it is conducted at a particular temperature. So can we say that ...
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29 views

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

Here is the correct answer from another stack website. The higher shunt resistance means that higher the polycrystalline lattice irregularity and many grain boundaries. This means higher current ...
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1answer
57 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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49 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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19 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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21 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
88 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
23 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
43 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
79 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
130 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
41 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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1answer
42 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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20 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
52 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
25 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
39 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 ''...
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1answer
182 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
21 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
54 views

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

I asked my material-science professor if forging a cast part (inside a mold to prevent shape change) can increase its strength to that of a forged part. She told me to find out myself and tell the ...
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1answer
58 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
71 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
70 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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16 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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2answers
15 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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2answers
51 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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39 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
524 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
695 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
36 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
16 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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15 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
44 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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11 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
75 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
95 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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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 ...