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dp
09-13-2012, 01:10 AM
http://www.sciencedaily.com/releases/2012/09/120911151945.htm

Doesn't take much to impress them :)

Evan
09-13-2012, 02:15 AM
The behavior was captured in movies that show the flow in color-coded layers just below the surface of the copper specimen. Copper is commonly used to model the mechanical behavior of metals.

Perhaps we should send them a note mentioning that "by the way, copper doesn't really act like most other metals..."

High thermal conductance, extreme and nearly instant work hardening from very soft to very hard, huge variation of ductility and the fact that copper and its many compounds have a range of anomalous magnetic and mechanical properties at the same mesoscale being studied.

darryl
09-13-2012, 02:37 AM
I think if you apply enough pressure the bonds between grains are going to give. These bonds are variable in strength, so the give is not going to be completely linear. It is no surprise to me that on that small of a scale there's going to be variations in how the grains move around. Now give me the research money please.

Black_Moons
09-13-2012, 03:40 AM
Next they are going to patent the forming tap.

rohart
09-13-2012, 04:44 AM
Maybe they'll stumble across friction welding if they carry on like this.

Forrest Addy
09-13-2012, 05:21 AM
They need to talk to some experienced bench machinsts. My view of a gall is it starts with a nucleation particle penetrating the oil film, followed by friction plating from relative motion, followed by momentary or intermittant adhesion producing a scratch that propagates laterally something like a boat wake. I've seen it in soft metals, hard metals, glass, waxes, large scale (glacier) small scale (watch screws) etc.

Galling is not a specific mechanism limited to an isolated class of materials. It's a general phenomenom widely found whereever closely fitted parts are subject to loaded localized bearing.

It's odd that galling is being investigated anew even though (dubious) anti-galling remedies have been around since the Egyptians. Soot and animal grease for example. Still works.

beanbag
09-13-2012, 08:12 AM
This sounds like a materials science issue, so I am kind of surprised it was on the cover of PRL, a respectable journal (not magazine) that is usually for physicists.

vpt
09-13-2012, 08:23 AM
What a breakthrough!

Duffy
09-13-2012, 09:34 AM
Forrest, Forrest, Forrest! Shame on you! To be so ARROGANT as to think that a PURE REASEARCH SCIENTIST would even CONSIDER asking a dirty-handed real-world metal worker his/her ideas on ANYTHING! WELL, I am shocked I tell you, SHOCKED!

lazlo
09-13-2012, 10:29 AM
This sounds like a materials science issue, so I am kind of surprised it was on the cover of PRL, a respectable journal (not magazine) that is usually for physicists.

That's the same read I get -- they're observing the effects of galling at the micron level.

Too bad you knuckleheads didn't publish your micrographs of fluid-flow at the point of contact, and noted the material folding was responsible for galling. You might have gotten a paper out of it :)

http://images.sciencedaily.com/2012/09/120911151945.jpg

Jpfalt
09-13-2012, 10:55 AM
You see a lot of this when you run the end mill backwards.

boslab
09-13-2012, 11:06 AM
The NHS in the UK had a rather interesting problem with hip joints, Galling perhaps?
mark
http://www.dailymail.co.uk/health/article-2114129/ALL-metal-hip-joints-banned-Failure-rate-times-higher-types.html

bob_s
09-13-2012, 02:19 PM
[QUOTE=boslab;795838]The NHS in the UK had a rather interesting problem with hip joints, Galling perhaps?
mark
/QUOTE]

Or corrosion caused by two metal contact.

Forestgnome
09-13-2012, 03:28 PM
That's funny! Sounds like they've discovered cutting as well. "The folding and cracking were most pronounced when the steel piece was held at a sharp angle to the copper surface".

beanbag
09-13-2012, 03:34 PM
Come on now. As scientists, they are interested in uncovering the first principles origins of Things That Everybody Already Knows. I can also assure you that many young and upcoming scientists are unaware of the concept of galling.

RancherBill
09-13-2012, 05:22 PM
This Post Doctoral research.

If the esteemed members of this Forum knew it all, this research would not have to be done. The research has been funded by the National Science Foundation, U.S. Army and General Motors.

Evan
09-13-2012, 05:31 PM
I don't take issue with the research however, the use of copper as a representative of metals in general is more than questionable. Copper has certain properties that are not common in the most often used alloys of many metals that are frequently used in situations where galling is a potential problem. Stainless steel alloys come to mind as do just about any alloy of steel in general. So does aluminum and its huge number of alloys. Insights derived from the investigation of copper are not likely to be directly transferable to other more commonly used materials.

boslab
09-13-2012, 06:26 PM
Here is another interesting one;
http://www.dtic.mil/dtic/tr/fulltext/u2/648744.pdf
While this refers to high vacuum welding by cohesion it is neither new nor radical, adhesive welding is also common in rolling mills, the mechanisms are similar, in a cold rolling mill there is a persistent problem with 'sticker wrench marks' where the strip steel momentarily 'welds' to the roll, there is visible tear out on the roll and steel strip, adding an increased amount of chrome to the steel seems to help but evidence is only anecdotal.
Also i have seen the effects of cohesive welding on slip gauges left wrung for too long
http://www.tresnainstrument.com/slip_gauges.html
altogether an interesting and 'sticky' subject
mark

lazlo
09-13-2012, 06:27 PM
This Post Doctoral research.

It's also in collaboration with Purdue, which is a top-tier engineering school.

uncle pete
09-13-2012, 06:47 PM
I could be missing the obvious scientific reasons, but isn't this is why lube is applied between two moving surfaces? That thin oil wedge is why a infernal combustion engine can roll over billions of times in it's lifetime. Without the lube? Your not going to get 10 seconds out of it. The reporter who wrote that must have missed the important points of what the test was actually trying to show.

Pete

Forestgnome
09-13-2012, 06:53 PM
This Post Doctoral research.

If the esteemed members of this Forum knew it all, this research would not have to be done. The research has been funded by the National Science Foundation, U.S. Army and General Motors.
My problem with it is there is no description of how this research differs from the reams of existing research using similar photographic techniques I've seen on cutting tool interaction with metals. By the way, the NSF is no stranger to useless research grants.

beanbag
09-14-2012, 01:26 AM
By the way, the NSF is no stranger to useless research grants.

OMG LOL u should see some of the [poop] people do on NSF money... I mean... we should all support science funding because science is very important for human knowledge.

RancherBill
09-14-2012, 09:57 AM
My problem with it is there is no description of how this research differs from the reams of existing research using similar photographic techniques I've seen on cutting tool interaction with metals. By the way, the NSF is no stranger to useless research grants.

Science Daily News is a newspaper! Back when Scientific American was scientific, I happily struggled through the biology and physics articles learning about new exciting topics. When they would do stuff on computers I would realize that the magazine was giving a layman's view of the topic.

I think it is kind of neat that they think they can make a mathematical model of the process. The picture is, to me, fascinating. They are pushing a wave of copper ahead of the tool. After the tool, you can still see all the layers, but, they are thinner.

There was a video posted here a few months ago showing a closeup of cutting action. It would be interesting to find out how much the resolution has increased on this new project.

Paul Alciatore
09-15-2012, 03:20 AM
I think what many here are missing is that this is NOT a scientific paper written by the researchers. It is a publicity piece which is probably written by a PR person who may not even have a bachelor's degree in any area of science, much less in the area of physics involved here. This person listened to (or read) the researchers description of what they were doing and wrote a piece of publicity. Not a scientific paper. Oh, and since the actual paper may not be published yet, the really important details would be withheld to prevent another researcher, who has better contacts at the scientific journals, from beating them to the punch.

It is surprising that the article is as good as it is. I certainly would not expect it to be informative as to the actual discoveries that were made.

PS: I too moan the fate of Scientific American. It used to be a good source of a general knowledge of new discoveries. Now it has degenerated to little better than Popular Science magazine and is of little value. You certainly will not get any real knowledge about the subject of the articles in it no matter how carefully or often you read them. Pablum.

Richard King
09-15-2012, 11:07 AM
Should show them how gauge blocks stick when you ring them together. They could get a billion dollar grant to study this. The main reason machine tools gall is from lack of lubrication and not dirt. That's why if your machine is cutting straight and the scraping is disappearing you can just 1/2 moon oil flake it or square cut the ways to add new and deeper oil pockets. :-)

dp
09-15-2012, 04:17 PM
I think what many here are missing is that this is NOT a scientific paper written by the researchers.

http://prl.aps.org/abstract/PRL/v109/i10/e106001

darryl
09-15-2012, 05:12 PM
It should be pointed out here that we are not knocking nano-technology (are we? ) or the things we will learn about matter through studying the realm of the 'ultra-small'. My personal feeling is that there is a surface here that we've barely scratched- there is enough to learn or know that would take a tome or two to convey. I predict a break-through in materials science on the nano scale, including a more or less abrupt increase in solar to electric conversion efficiency.

Mcgyver
09-15-2012, 05:34 PM
a lot hubris in this thread.


Perhaps we should send them a note mentioning that "by the way, copper doesn't really act like most other metals..."
.

really? go ahead, here's his email: chandy@purdue.edu

A PhD and full professor and you want to start by telling them how they doing it all wrong? A more intelligent approach (many here should consider) is asking questions when you don't understand something; often enlightenment follows. Prof C, why do you use copper...."

As a general comment, I don't think anybody here (self included) has a clue what's going at the molecular level between sliding surfaces. Always been that way and me pappy told me so are hardly reasons....and a lot of what gets posted seems conflicted with the science and engineering writings in the of bearings and tribology, or at least there's bits missing or not fully explained. Me, I want science and engineering, have no time for religion and find the know-it-all attitude is unbecoming....if somebody here does read the paper perhapos we could learn something?

lazlo
09-15-2012, 06:34 PM
http://prl.aps.org/abstract/PRL/v109/i10/e106001

That's an excellent paper. I have access to the full version via Cite Seer if anyone's interested.


"Using in situ imaging, we report surface fold formation and fluidlike flow instabilities in sliding of annealed copper. We demonstrate using simulations that folding is principally driven by grain-induced plastic instability. The phenomenon shows remarkable similarities with Kelvin-Helmholtz-type flow instabilities in fluids. While such instabilities have been conjectured to exist in sliding interfaces at the nanoscale, we find vortices and folding in metals at the mesoscale. The occurrence of folds impacts many applications, including surface generation processes and tribology."

They link to a companion article from the Department of Materials Science at the University of Saarlandes (Saarbrücken, Germany). It walks you through the micrograph I posted above:

http://physics.aps.org/assets/ae7e6dae29cd7359

"Figure 1: Schematic sketch of the temporal and spatial evolution of the folding instability: The wedge, moving from right to left, displaces the material in the machined solid, causing a compressive stress in front of the wedge. (1) Due to this compressive stress, the grains with a larger deformability already form bumps several hundreds of microns in front of the wedge. (2) When different bumps are close enough, they often interact to form a fold. (3) Under the wedge the fold is flattened to finally form a tear (4) when it reappears from underneath the wedge. Thin red lines represent streak lines indicating laminar flow away from the surface."

BobL
09-15-2012, 08:40 PM
I've been interviewed a few of times about my research. One interview was on nuclear waste. I provided a number of appropriate photos and drawings but the reporter/editor chose to run with one picture, of a child carrying an antinuclear poster and a black and white peace sign painted on their face. On another occasion the interview was about cosmic dust. Most of the published article was spent discussing a song called Stardust, composed in 1927 by Hoagy Carmichael? Another time I spent half an hour on the phone with a reporter trying to get me to to agreed with his points of view on nuclear energy - when I wouldn't give him the quotes he wanted he said the story was unlikely to run as it wasn't newsworthy enough. After that I stopped talking to reporters.

Forestgnome
09-16-2012, 10:04 AM
Okay, I still don't get what's new about this research. I look at the diagram and I see the same thing that happens in many materials when they're pushed. You can push dirt with a bulldozer and see the same thing. Obviously I'm missing something.

Evan
09-16-2012, 11:32 AM
Plastic behaviour in metals is in no way a surprise. It happens at all scales and with all metals.

Evan
09-16-2012, 11:37 AM
a lot hubris in this thread.

Oh really? I am very well informed by both theory and long personal practical experience. Letters after a name do not make a person superior to another, knowledge and experience trump credentials every time. I also do a significant amount of research of my own in the same area.

Incidentally, I also have over 200 semester hours of credit. That's enough for a masters in engineering, either mechanical or electrical.

vpt
09-16-2012, 11:46 AM
I agree, I still don't see any break threws or "new" information here. But seeing these galling pictures all I want to do is grab a hammer to pound the hill back down and stone flat.

Mcgyver
09-16-2012, 11:56 AM
Oh really? I am very well informed by both theory and long personal practical experience. Letters after a name do not make a person superior to another, knowledge and experience trump credentials every time. .


and that's not over the top hubris? You know as much and have done as much research as these men in this discipline? In between fixing photocopiers and running a computer store? its not letters its the time, attention, intelligence, specialization and resources they represent.

btw, did you read the paper?

how do you even have access to the things you'd have to read to be well informed? Not newsy reporting magazines like the link or SA, but real scientific journals. Most are a small fortune to subscribe to and you usually have to be part of fairly high end research institute or university to get access online or through their library. Few public libraries would subscribe to any but most common and then they are in the reference section of the main branch.

did you email him advising he's going about it wrong? I provided the email address.

The hubris isn't thinking you know a lot, its the "I'm right, he's wrong" response. I suspect it was done without having read the paper. The hubris causes the assertion reaction rather than the more sensible asking of a question "why does he use copper".

Evan
09-16-2012, 07:11 PM
In between fixing photocopiers and running a computer store?

I have done far more than fix photocopiers.


You know as much and have done as much research as these men in this discipline?

No idea. I haven't met them. I do know that copper is not representative of the majority of metals, especially the ones normally used in applications where galling is a problem. One does not require a PhD to figure that out.



how do you even have access to the things you'd have to read to be well informed? Not newsy reporting magazines like the link or SA, but real scientific journals.

Many are online and have free access to many of the articles. They seem to have discovered that a paywall simply means that nobody else will cite the papers.


The hubris isn't thinking you know a lot, its the "I'm right, he's wrong" response. I suspect it was done without having read the paper. The hubris causes the assertion reaction rather than the more sensible asking of a question "why does he use copper".

You have missed the point. Go back and read the article. It states that copper is used to represent other metals. Poor choice if that is the reason. I have no reason to believe that that statement was not correctly representing the study.

Your problem is in thinking that because you don't know much about a subject then neither can anybody else if they aren't some sort of professional scientist. I have a rather large library that covers many subjects in the sciences and I read in the range of five or more hours per day from it and on line, all of it non fiction and nearly all of it science related. Materials science is one of the areas in which I am extremely interested and have not just studied but also experimented a lot. I also have some pretty good micrographic equipment for the purpose. The things I am missing are an electron microscope and an atomic force microscope. The latter is buildable, the former more difficult.

Your primary problem though is resorting to ad hominem attacks on other members. That is unproductive and resolves nothing. It adds nothing to the discussion. It makes many of your posts worthless.

Forestgnome
09-16-2012, 11:22 PM
Not specifically referring to the scientists in the article, but you could earn 5 Phd's and still not have a lick of sense or have intuition about the world around you.

aostling
09-17-2012, 12:44 AM
Not specifically referring to the scientists in the article, but you could earn 5 Phd's and still not have a lick of sense or have intuition about the world around you.

I have worked with PhDs who were creationists. I have no idea how they could believe in science and disavow it, without imploding.

Not that it matters much, but the researchers in the article are industrial engineers, not scientists.

Mcgyver
09-17-2012, 08:26 AM
IYour primary problem though is resorting to ad hominem attacks on other members. That is unproductive and resolves nothing. It adds nothing to the discussion. It makes many of your posts worthless.

what ad hominem attack? I attack BS, it's what gets me going :). Are you referring the photocopy repairman/computer store point? Each is a perfectly respectful vocation....the point was time and attention. You wouldn't have access to the same info or the time compared to what someone in post graduate work is doing at a major university.

You would go on for 100 posts about it accomplishing nothing insisting you're right (as per always).... but I think the point is made, when in ignorance it's better to ask questions than barge in making assertions


I have worked with PhDs who were creationists. I have no idea how they could believe in science and disavow it, without imploding

you can have PhD's in just about any subject, some of which I'd have no use for nor would such subjects conflict with wacky beliefs. I'm hardly arguing PhD's are the be all end all in every instance....but do you think it makes sense to assume and assert how a PhD and full professor of physical sciences working in his field of study is going about it wrong....in reference to a paper you haven't read?

dp
09-17-2012, 08:35 AM
The days are getting short, the shops are getting cold, and people are getting crabby. The turning of the seasons at HSM has begun.

Mcgyver
09-17-2012, 08:44 AM
The days are getting short, the shops are getting cold, and people are getting crabby. The turning of the seasons at HSM has begun.

lol you may be right.

Evan
09-17-2012, 09:07 AM
what ad hominem attack? I attack BS, it's what gets me going

You do know what "ad hominem" means, don't you? It's an attack on the person rather than the argument. The term "hubris" means "false pride". That is an attack on the person and therefore an ad hominem statement.

So is your statement I just quoted above. What BS did you mean in particular? Try to justify your opinion with a reasoned argument instead of calling my statement BS.


You would go on for 100 posts about it accomplishing nothing insisting you're right (as per always)..

And yet again...

My reply above (#36) contained several ad hominems against you just to illustrate the point.

lazlo
09-17-2012, 09:31 AM
I have worked with PhDs who were creationists. I have no idea how they could believe in science and disavow it, without imploding.

I'm going to have to call bullsh!t on that Allan. :rolleyes: I've worked with some of the brightest Ph.D.'s on the planet, and in my 30 years in the field, I've never run across an engineer or scientist who was a creationist. Not surprisingly, most engineers and scientists are agnostic -- we have a problem believing in anything based purely on faith ;)


Not that it matters much, but the researchers in the article are industrial engineers, not scientists.

That's shocking coming from you Allan! They're researchers at the Center for Materials Processing and Tribology, Purdue University!

There are tens of thousands of engineers spending decades doing Navier-Stokes fluid-flow analysis for aerospace design, internal combustion engines, weather analysis, and yes -- laminar flow in materials.

"Ah don't need no high falutin' numbers to know how a engine wurks -- ah pull the cord, an it starts!" :D

Sigh. This forum can be so unsophisticated...

Mcgyver
09-17-2012, 09:33 AM
You do know what "ad hominem" means, don't you? It's an attack on the person rather than the argument. The term "hubris" means "false pride". That is an attack on the person and therefore an ad hominem statement.
.

good grief, there was no deflection from the argument toward personal attack, the hubris present in this thread and from you is the argument and subject of the post. false pride? Misplaced arrogance is a common definition.

I'll repeat myself: The hubris isn't thinking you know a lot, its the assumed "I'm right, he's wrong" response - given it was directed toward someone steeped in credentials where you have none and I suspect it was done without having read the paper. The hubris causes the assertion reaction rather than the more sensible asking of a question "why does he use copper". [/I]

Done with this nonsense.

Evan
09-17-2012, 09:36 AM
I'm going to have to call bullsh!t on that Allan. I've worked some of the brightest PhD's on the planet, and in my 30 years in the field, I've never run across an engineer or scientist who was a creationist.

I have met a mining geologist that also believed the Earth was only 6500 years old. That is some pretty good compartmentalization.

Evan
09-17-2012, 09:37 AM
Done with this nonsense.

You shouldn't have begun it.

boslab
09-17-2012, 05:36 PM
I have met a mining geologist that also believed the Earth was only 6500 years old. That is some pretty good compartmentalization.
Ah i see the J Witnesses have spread, I have a local infestation too!, I Do Believe in a God, I just don't like religion myself, makes life complicated when you listen to words written by liars
, after the event!
Lots of reasearch comes across as bollocks when you have a wider knowledge, a PHd is a qualification of minuscule proportion, it may be xray crystallography of al2o3 or laminar flow in Cu alloys or gamma brass impact strength, all of which i have had the misfortune of reading, however there is no PHd that gives a wide ranging qualification or knowledge, the peer review process is also very narrow.
A mechanic can have a wider knowledge than a doctor of materials engineering, trust me on that one, i work with PHds every day and some of their final thesis's are so specialized they get reviewed on the basis of its so complex they must know what their talking about!
If you want to know how things work in any organisation ask the janitor, not the boss!
all the best
mark

beanbag
09-18-2012, 01:24 AM
Hey guys, did anybody read the actual paper?
They did not say that copper is representative of all metals. I don't know about the rest of their research, but there were probably a few reasons they used copper. It happens to be softer than their scraper pusher tool thing. It is a pure metal, as opposed to an alloy, so it is crystalline at some mesoscale. It is relatively simple so that they can compare to FEA results etc

They can discover and analyze the effects in an "easy" system first and then expand to more general cases.

The word "metal" only appears in the abstract, the first paragraph, and the last paragraph. This is the very standard scientific writing technique of "make my research sound important and useful to everybody else".

Maybe wait for either the PRB version where they don't have the 4 page limit, or maybe they will have a dumbed down version in scientific american or something.

philbur
09-18-2012, 12:41 PM
The professor in question is Srinivasan Chandrasekar. He is professor of materials engineering at the University of Purdue IN. Two student graduates working under him work specifically in the study of deformation of metals during processing. However apparently by the standards of this forum he/they don't know squat. Clearly our in-house Professor of Everything is far more knowledgeable in ... well everything actually.

Once again Priceless.

Phil:)