Questions tagged [material-science]
168 questions
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Why doesn't epoxy stick to silicone?
Why doesn't epoxy stick to silicone? Is there a type of epoxy that does?
Geremia
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11
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4 answers
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?
Adam
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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 explains the sign and magnitude (to some…
user586228
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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 is particularly because of the fact that the…
user586228
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4
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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 environment, I have no little idea. Please help me about…
Satya
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4
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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 This answer and comments claim:
Wall thickness…
mart
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How the choice of etchant can affect the severity of hydrogen embrittlement during pickling and passivation?
Following this question, I am trying to understand how/if the choice of acid we might use during the pickling and passivation of certain metals, can influence the severity of hydrogen embrittlement. To my best understanding, all etchants will induce…
Foad
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Plastic hardness after machining vs molding
Should there be any difference in the hardness of a plastic material that is machined vs one that is pressed from a mold?
This question is in specific reference to vinyl record production where records pressed/stamped from molds are seen to be more…
Lukas L
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3
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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 halt and incurs some degree of smash damage.
An…
Lorry Laurence mcLarry
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3
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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 standardized list of k-factors that they either use or…
Kapfy
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3
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2 answers
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 clear difference between the two and some simply defined the…
Sophia
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3
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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 elasticity. In reality, these values may be…
S. Rotos
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What KB means in 38NiCrMo4 (KB)?
I've been dealing with an engineering drawing that has a material called 38nicrmo4(kb) in Italian UNI standard. It appears that it is equivalent of 36crnimo4 in DIN or commercially named VCN100.
In the drawing "kb" part is absent and it has had me…
2012User
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What practical use is knowing the extrusion direction for a piece of polycarbonate?
I noticed after cutting this piece of polycarbonate that there is an extrusion direction indicated. Can that be useful for cutting or other downstream use?
user391339
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What determines the rate of electron discharge machining (EDM) for different materials?
Wire EDM makes no contact with the work piece and disregards hardness.
I am using EDM to cut different materials, and I notice a clear distinction between the rate each material gets cut. For example, copper is extremely slow, while aluminum is much…
FlakR
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