/r/materials

Photograph via snooOG

Reddit for Materials Science and Engineering topics

Materials science - an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. With significant media attention focused on nanoscience and nanotechnology in recent years, materials science has been propelled to the forefront at many universities. It is also an important part of forensic engineering and failure analysis. Materials science also deals with fundamental properties and characteristics of materials.

Wikipedia: Materials science

Related subreddits:

/r/materials

18,084 Subscribers

7

material like ice that won’t melt (so my cats can chase it)?

my cats loveeee chasing ice cubes but i feel bad since they always melt. is there something slippery like ice but won’t melt?

7 Comments
2024/02/25
04:10 UTC

3

Oil on the surface of PVC tubing

I have been working on an art piece that involves filling PVC vinyl tubing with baby oil, food coloring, and water. I recently noticed a lot of my pieces have oil droplets on the surface of the tubing and I am trying to figure out why this is happening and what I should be doing to avoid it.

Currently, I have 2 theories

https://preview.redd.it/jwoo0w9qzlkc1.jpg?width=3024&format=pjpg&auto=webp&s=e8bb832058a8f026e3fc581e483187beec947277

  1. The baby oil is breaking down the plastic. But I keep seeing articles stating mineral oil-based lubricants don't attack most plastics, which is what baby oil is composed of.
  2. Some of my art pieces I have heated up with the oil inside to reshape the tubing and perhaps that is bringing the oil to the surface? All pieces have the tubing heated beforehand to relax the tubing shape that was held in the warehouse but a couple of pieces are then reheated with the oil and water liquid inside for me to reshape again.

What do people think is going on? Any suggestions on what I should do and how to fix this issue?

0 Comments
2024/02/24
22:24 UTC

0

Plastic breaks

this design seems good for metal but not plastic, not sure about other materials

1 Comment
2024/02/24
04:23 UTC

47

Some oxides are more equal than others

"Patina is the name for rust that we want"

0 Comments
2024/02/24
03:29 UTC

1

Off topic - toilet components

Hi everyone, I'm looking for advice for a goofy home improvement project. Years ago I modified a frustrating low-flow toilet to generate a more manly, full-tank, tsunami level flush.

I used stainless steel for the connecting parts. To my dismay, however, my mechanism corroded away after approx 8 submerged in water/bleach.

Can anyone think of a material or coating that might hold up better under these fairly hostile environmental conditions?

3 Comments
2024/02/23
17:59 UTC

2

Intro to semiconductors

Hey all,

I would like to get into semiconductors (and maybe end up working in the semiconductor industry). Currently an undergraduate student in MatE.

Any books/resource recommendations? Any advice for the field? Is a Masters/PhD needed/useful for the semiconductor industry?

Thanks!

9 Comments
2024/02/23
03:04 UTC

0

4 parameter model question

Em= 120 MPa nm= 88 GPas Ev= 180 MPa nv= 1440 MPas

(a) Initially, a load sigma_not= 15MPa was applied. Suppose this load is removed at t=100sec and you wait a very long time (t>> tau). What will be the residual strain?

(b) Suppose the load is never removed. What will the strain be in the limit of extremely long times?

Any help is appreciated!

0 Comments
2024/02/22
22:15 UTC

2

Injection Molding for PHA

I'm currently running a senior year design project where we want to create an injection-mold friendly blend of PHA. We're currently looking at Calcium Sulfate and Microcellulose as additives to increase tensile stress, but we were looking for something to reduce crystallinity in the blend. Are there any additives that work with PHA or similar polymers that would have this effect?

0 Comments
2024/02/22
21:23 UTC

11

Day in the Life

Hello,

To all the materials engineers and materials scientists, could you describe what a normal day in the life looks like for you? I am curious to know, but it is hard to find anything online for this. Thanks!

8 Comments
2024/02/22
02:13 UTC

0

See-through heat conductive material for brazen-bull torture

Hey guys,

I am sure many of you are familiar with the ancient Greek torture method "Brazen-bull" where a victim was placed inside a hollow brass bull, which was then heated until the metal became unbearably hot.

I was wondering, hypothetically and in the interest of studying the science of torture of course, what material could be in today's age used to create the bull so that it would be see-through while maintaining enough heat conductivity for effective torture.

So what material would you use today?

12 Comments
2024/02/20
18:29 UTC

2

Does UK Tippex Correction Tape deteriorate over time? (Ideally in a predictable way)

Hi there, I've always been a bit in awe of the level of the people on this thread; I hope it's OK to ask my question here.

My question is this; I'm sure that correction tape (in this case UK Tippex Correction Tape, like a "mouse" dispenser) isn't Archival standard, but does anyone have any experience with how it ages over time?

My gut tells me it would either yellow or shrink and crack over time. A lot of that would come down to its UV exposure, I'm sure, but the paper it's on isn't on a notice board or anything like that.

Any thoughts on how stable UK Tippex Correction Tape is over about 20/25 years? Or if I could tell it's it application is more recent?

BTW, I checked and it was introduced to the UK in 1992 but the document I'm trying to figure out is from 2000 - that would have been a VERY easy answer 😃

0 Comments
2024/02/20
13:31 UTC

0

Best gripping material for a project

Please give suggestions on good gripping for a project. Planning on applying it on wheels for a robot so that it can withstand a great amount of pushing. Suggestions will be greatly appreciated

5 Comments
2024/02/19
18:20 UTC

2

Hardenability of Steel

Hello,

I am looking for some reference material on SAE steel grades for hardenability curves and other general data books. Does anyone know any good reference links or materials? I've found some links that appear to be behind paywalls but don't want to waste resources for info I possibly won't need.

3 Comments
2024/02/19
15:25 UTC

6

Cracking problem under small but long-term loads

We have a product and we have a problem with cracking after a certain period of time. We cannot experience this in our own workshop, this problem occurs during the use of the product in the field, for example after 3-4 months. Which test method should we use to test its strength under small but long-term loads? We have a tensile strength testing machine, but does this test method give an idea about this problem? Or should we apply impact strength test? We got confused. Thanks in advance.

https://freeimage.host/i/reddit-soru-1.JE8lERn

7 Comments
2024/02/18
12:40 UTC

0

What if every mass is a time crystal? The idea is that mass isn't curving the geometry of space, it's increasing the density of time in the area around mass. A Unified Field Theory is core to all science including Materials Science and Engineering.

What if every mass is a time crystal?

The idea is that mass isn't curving the geometry of space, it's increasing the density of time in the area around mass. At a large scale we experience this as gravity, the curvature of paths in space, and effects like time dilation. At the quantum scale what is happening is that space is updating more frequently in areas near mass, and this creates the gravitational interaction, instead of a gravitational force, it is changing the odds that a particle will move towards mass. As the additional density of time, is at the quantum scale the same as an additional area of space, it is warped space in time.

To explain in more detail I have included a long article about it, two long articles, both of the articles contain equations, the first article has some drawings. I will answer all serious questions about this theory. Please be a nice person though if you wish to have real dialog.

First article:

New Unified Field Theory: Quantum Gradient Time Crystal Dilation: explains quantum mass as a time crystal dilating time at quantum scale & making gravity by increasing time frames. https://www.svgn.io/p/a-new-unified-field-theory-called

Second article:

Quantum Gradient Time Crystal Dilation breaks the assumption that gravity equals metric curvature alone.

Unveiling the Fabric of the Cosmos with QGTCD, a Unified Field Theory, Part II: Christoffel Symbols, a Slow Metric Tensor, Theoretical Considerations & Challenges. https://www.svgn.io/p/quantum-gradient-time-crystal-dilation
This theory is published on substack & github for the world to review. I'm hoping folks can provide quality professional feedback before I upload them to ARXIV as this theory is an early stage pre-pre-print.

1 Comment
2024/02/18
10:16 UTC

0

Finding the right material

Hello all. I’ve been struggling to find the right sort of thing for my needs with a new product. The issue I face is simple.

I’ve designed something that needs to tightly slip over the outside of a cylinder. I have the fitting right but because of the materials used for manufacturing it won’t grip to the cylinder as tightly as I’d like.

My plan is to get something similar to a silicone hot cup sleeve but elasticated- however I need it to be much much thinner. Like 0.1mm thin and 25mm wide but I can’t find anywhere in the UK online that can offer something like that. Can anyone help advice a place or a term I can search up to find what I need?

3 Comments
2024/02/17
19:35 UTC

3

Sorbothane in space

Hi all, trying to understand how a viscoelastic urethane like Sorbothane would perform during a rocket launch. I am considering this material to damp vibrations and absorb shock in order to protect sensitive electronics.

But does it work in a vacuum???

As the rocket reaches closer to low earth orbit, there will be almost no atmosphere, so could the Sorbothane still damp / absorb when there is no air to convectively cool it? It is my understanding that these forces are only dissipated by releasing the deformation energy as heat.

Thanks for your thoughts!

0 Comments
2024/02/17
12:53 UTC

1

What sort of properties (electrical / thermal / tensile) should one expect from a sintered aluminum bar?

I'm a hobbyist that tinkers with additive / other sintering techniques (lately it's been mostly microwave sintering) and I've achieved moderate success to my untrained eye, but wondering what expectations I should actually have for parts sintered in my workshop? I've measured electrical resistance and have a basic tensile strength rig, but it's been hard for me to find other references to guage how well my samples actually compare to industry... help?

12 Comments
2024/02/17
03:22 UTC

6

What material has the highest elastic energy storage per Kg?

What material, if made into an idealized spring, could store the most amount of energy per Kg of material? How would that compare to chemical energy per unit mass of lithium batteries or gasoline?

10 Comments
2024/02/16
18:46 UTC

1

Selecting tools for my metallography lab

Hello,

Building a metallography lab in the US here. Thinking of having a high-speed saw, low-speed saw, auto polisher, vibromet, and microscopy. I have some brands off the top of my mind like Buehler, Allied High Tech, and Struers. We're looking at criteria like well-function, durability, customer service, etc. Does anyone have any experience using equipment from these vendors before? Thanks!

P/S: reposted from another subreddit as wanting to get as much info as possible.

14 Comments
2024/02/16
15:19 UTC

1

Can you make a sink out of scagliola, or add an additive to the scagliola mix to harden it and make it resistant to water? or seal it?

" Scagliola is vulnerable to water ingress. Being made of gypsum, it will quickly return to its natural state when water is added. Water running over the surface will etch runs and pitting as it washes out the gypsum. If soaked, salt crystals will effloresce on the surface of the scagliola as it dries, as crystals of calcium sulphate migrate and form on the surface. Water will also loosen the bond between the surface and deeper layers of the build-up, leading to delamination and an abnormally hollow sound when tapped. Prolonged exposure to moisture will eventually weaken and destroy scagliola. " But could you make a variation of scagliola that is resistant to water?

3 Comments
2024/02/16
15:12 UTC

3

I would like to learn something useful in practice about materials for mechanical engineering

I am a mechanical engineer and all my academic and (short) professional experience brought me to focus mainly on topics like turbomachinery, robotics, mechatronics, mechanisms design... Always neglecting or giving for granted topics related to materials.

To make an example, the kind of problems and solutions I addressed were of the kind "I need something to be light" "Then use aluminum, or eventually titanium if you're rich" without even knowing what alloys actually exist and their properties. So just going with the flow of stuff I heard around.

I would like to get a bit more of a consistent background on the subject of materials science and engineering. I know some basics about materials behavior (dislocations, cristalline lattice, some treatments, composites...) but especially on the practical side I would like to be able to understand/make some educated guesses in real situations.

Can someone suggest some sources? A YouTube channel would be great. Also academic books of lectures would be nice.

Not that I will ever make of that my main business, but I don't like this kind of unconsciousness :)

2 Comments
2024/02/15
22:00 UTC

0

Heat resistant fabric?

6 Comments
2024/02/15
17:52 UTC

2

Does anyone know of any heavyweight materials that are also thermally insulative? (similar density to brick)

As the title says, I'm looking for a material that is a similar density to brick or concrete that is thermally insulative (a lot more than brick). Looked around online but couldn't find any great answers.

Many thanks in advance!

10 Comments
2024/02/15
15:51 UTC

11

New Episode of the Materialism Podcast on Radar Absorbing Materials (Links in Comments)

3 Comments
2024/02/15
14:46 UTC

2

Measuring Tensile Strength

Hi,

I'm trying to compare the tensile strength of different materials. They were measured using different methods, one was measured using a WDW-05 electromechanical tester and the other with a commercial tensile tester (Instron 3343), the samples were prepared using different shapes and sizes. I'm sure it would be better to use the same test on both, but are they still comparative?

I'm not sure if there are drawbacks on either as I'm not familiar with these tests?

Thanks so much

14 Comments
2024/02/15
13:38 UTC

4

Dilemma to choose Study specialization

So, I am doing my masters in Material Science and Engineering and I have to choose a track on my next semester. One track is Smart surfaces and Functional Materials and the other is Advanced Metallic Materials.

I am kinda swinging between which tracks to choose because both seem really interesting to me.

Any experts here who can give me some points which would help me make a decision?

8 Comments
2024/02/14
17:02 UTC

0

Garry Nolan presents preliminary data from unusual materials allegedly recovered from UAP sightings

4 Comments
2024/02/14
07:44 UTC

4

Is there an acoustic impedance database?

Is there a database that has the acoustic impedance values of various materials?

Like I need to find a material with an acoustic impedance of 7.3371 MRayl or close to it. I need several others for various impedance values.

Any thoughts or suggestions are greatly appreciated.

2 Comments
2024/02/13
00:04 UTC

Back To Top