# Questions tagged [material-science]

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### 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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### 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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### Can someone explain to me von Mises equation for multi-axial (2D or 3D) stress

I am trying to understand what is in the wiki about the multi-axial (2D or 3D) stress https://en.wikipedia.org/wiki/Von_Mises_yield_criterion An equivalent tensile stress or equivalent von-Mises ...
3k views

### Why would the flexural modulus be different than the elastic modulus?

I'm reading the Wikipedia page on flexural modulus. It is said: Ideally, flexural or bending modulus of elasticity is equivalent to the tensile modulus (Young's modulus) or compressive modulus of ...
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### 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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### 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 ...
33 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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### 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 ...
28 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 ...
78 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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### 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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### Determine compressive modulus from compressive strength data in spec sheet?

Is it possible to determine the compressive modulus of a polyethylene foam using the following spec sheet? Minicel Type M Foam It doesn’t contain any information regarding the compressive modulus, ...
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### 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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### 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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### 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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### 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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### 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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### 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 ...
40 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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So, I did a quick search around and didn't seem to find anything regarding this, so I thought perhaps I should just ask a question. Metals are malleable and will generally flow/deform if you roll it ...
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### 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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### 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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### 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.
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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### 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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### 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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### 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 ...
180 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 ...
692 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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### 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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### 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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### 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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### 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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### 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 ...
57 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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### 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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### 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 ...
516 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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### 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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### 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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### 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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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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### 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 ...
60 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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### 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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### 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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### 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 ...