Questions tagged [materials]
Use for questions about designing, manufacturing or synthesizing engineered materials or about the properties of specific materials. Questions concerning common construction materials, such as wood, steel or masonry do not need to use this tag; use the more specific tag instead.
922
questions
88
votes
9
answers
40k
views
Why do glass windows still exist? (Why haven't they been replaced by plastics?)
Glass is fragile and impractical to transport, install and repair. Even worse, glass kills and hurts people when it breaks. Falling to the streets like guillotines during earthquakes and bomb raids. ...
- 1,073
38
votes
10
answers
44k
views
Is it possible to build a perfectly spherical Prince Rupert's drop?
Prince Rupert's Drops are glass objects created by dripping molten glass into cold water. While the outside of the drop quickly cools, the inside remains hot for a longer time. When it eventually ...
- 778
19
votes
1
answer
981
views
Can we change steel properties by application of magnetic field while quenching?
Austenite is non magnetic while $\alpha$-ferrite and pearlite are magnetic. (Magnetic properties of pearlite vary as a function of carbon content)
If a strong magnetic field is applied in a ...
- 1,413
19
votes
1
answer
5k
views
How many train passes can railway tracks endure?
I know that the rubber on car and truck tires wear, and the road concrete wears out. I wondered:
While steel is hard and elastic, it still causes friction (interaction
between molecules) and ...
- 409
18
votes
2
answers
5k
views
Why doesn't epoxy stick to silicone?
Why doesn't epoxy stick to silicone? Is there a type of epoxy that does?
- 407
15
votes
2
answers
14k
views
Why do we even use engineering stress?
Surprisingly this hasn't been asked before, so I must be missing something simple.
We use engineering stress and engineering strain in this eq. Stress = (Young's modulus) × (strain). This eq. is ...
- 153
14
votes
7
answers
31k
views
Is stainless steel plating possible?
Is there a method for plating steel with stainless steel?
If so, is it chemical, electrical, or electrochemical?
I did a quick search on the internet but was unable to find a service. I'm ...
- 495
14
votes
1
answer
1k
views
Why does prestressing in trees make them stronger?
In "Structures: or Why Things Don't Fall Down" James Gordon talks about trees being prestressed with the outside in tension and the inside in compression. Why does it make a tree stronger to have it ...
- 141
14
votes
1
answer
756
views
What are some cost-effective metal substances that can wet glass?
A highly desirable property of metals like gallium and indium is that they are able to wet glass.
Normally, as metals, they wouldn't be able to form an airtight seal when in contact with glass. But ...
- 611
14
votes
3
answers
240
views
Looking for best material for a cryogenic ball mill cup and balls
I am working with a set of alloys that must first be ground up in a ball mill at cryogenic temperatures. It is important that no contamination makes it into the material and careful steps are taken to ...
- 716
13
votes
3
answers
2k
views
Do I need to worry about galvanic corrosion when inserting a steel bar through aluminium?
My design uses a round steel bar inserted through a hole in an aluminium component with a tight fit (no movement). The operating environment is dry, 20-40°C.
Do I need to worry about galvanic ...
- 5,970
13
votes
5
answers
4k
views
Are there any materials known to be sound-insulating but thermally-conductive?
Are there any materials known to be sound-insulating as well as thermally-conductive?
Cost is not an overriding concern, but preferably costing "reasonable amounts" and much less than national ...
- 230
13
votes
1
answer
1k
views
Can Zinc/Aluminum coated anchor rods be used in concrete?
Bolts and anchor rods that are very high strength ($F_u$ > 150ksi) are not supposed to be galvanized. This is because of concerns about hydrogen embrittlement. This includes ASTM A 490 bolts and ASTM ...
- 10.7k
12
votes
7
answers
8k
views
Why does a gear have extra holes?
In a gear you normally have a center hole for the shaft to be put into. Why do some gears have holes surrounding that center hole?
Is it for weight reasons? Does it add stability? Is it so you can add ...
- 265
12
votes
1
answer
486
views
Is steel relaxation plastic?
Hooke's Law defines a linear-elastic relationship between stress and strain.
$$ \sigma = E\epsilon $$
Steel behaves very much like a linear-elastic material, following Hooke's Law closely. It does, ...
- 13.1k