Talk:Ductility

Not really a material property

ductile is not really a material property but rather related to the fracture of the correct mechanics. steel will have a ductile fracture if heated enough. enough frozen gold will have brittle fracture mechanics. have you ever tried to put a rose in a bath of liquid nitrogen and then drop on the floor?

bedrupsbaneman What do you mean by ductility?

17:02, 18 October 2005 (UTC)

Most and least ductile metal?

Gold is the most ductile metal, what is the least ductile metal?

Surely platinum is more ductile?

No, gold is correct. The least ductile is hard to define, because of the ill-defined differences between metals, semi-metals and non-metals, but see e.g. tin pest for a very brittle allotrope of tin - MPF 14:27, 2 February 2006 (UTC)

I'm sorry, you're wrong. Platinum is more ductile than gold. You have to understand that gold is the solid metal (at room temperature) that can be hammered to the finest sheet possible (malleability) and that the longest wire ever extruded from a die (ductility) was made of extremely pure platinum. Please read the topic "References that are unreliable, better books to replace them" in this same discussion page and check the books I mentioned, they're highly reliable, much more than a book about materials for sculpture...which says it all.82.240.163.245 (talk) 21:52, 4 January 2012 (UTC)

You are correct; gold is one of the most, if not the most, malleable metals, while platinum is the most ductile. Ductility and malleability differ. — Preceding unsigned comment added by 68.32.64.203 (talk) 23:29, 5 December 2018 (UTC)

I am pretty sure that Indium is softer than gold. (Mohs hardness and Brinell hardness are lower). So I guess it is more ductile. The malleability is more complicated because I guess this has to do with shear hardening, but it might even be more malleable. —Preceding unsigned comment added by 84.75.180.70 (talk) 22:23, 15 February 2011 (UTC)

this is not a stupid question at all. Indium's property to stick to itself , being a pure metal, solid at room temperature, and it's "softness" which makes it much more easy to plastically deform (at room temperature again) than pure gold , all this tells me that you have to find a paper or a study which compares it to say gold , platinum and silver, but myself I haven't found any, I find this odd.If anyone finds such a (reliable) comparison, please include these elements in the article.82.240.163.245 (talk) 21:54, 4 January 2012 (UTC)

I was just about to come post a question about qualitative measures. :) Are Mohs hardness and Brinell hardness the closest/only numeric measurements of malleability and ductility? I wanted to volunteer/seek guidance on making a chart to show the relations between the metals in this sentence in the article:

The following list ranks metals from the greatest ductility to least: gold, silver, platinum, iron, nickel, copper, aluminium, zinc, tin, and lead.[1]

--— robbiemuffin ^{page talk} 11:56, 14 April 2011 (UTC)

Robbiemuffin, your list is worthy of the 19th century, it is a carbon copy of lists found in encyclopediae of materials published starting in approx 1820 in Great Britain. This list you mention is outdated and not based on recent research, but I agree that it is also extremely difficult to find reliable lists: engineering books only speak of the most ductile (platinum) and the most malleable (gold) but fail to provide similar long lists( short lists are available but differ from the outdated one you posted), after all it's not so important to nowadays' industry ...for the moment, but this time will come very soon when such lists will be needed.82.240.163.245 (talk) 21:53, 4 January 2012 (UTC)

The claim for platinum is based on a wire pulling technique that because of different melting points can't be applied to gold. And strictly speaking, it isn't a proper measure of ductility anyway. So, AFAIK, at this point, the alleged greater ductility of platinum is, at best, speculative. See the section on "Measurement" further down in this talk page. Also see:

http://www.technology.matthey.com/resources/view-questions-answers/platinum-ductile-gold/

Plasticity?

What is the difference between plasticity? If there is no difference, should these pages merge? —BenFrantzDale 21:03, 8 December 2005 (UTC)

According to a professor, plasticity is the phinominon whereas ductility is the property. —BenFrantzDale 16:56, 14 December 2005 (UTC)

Plasticity is also a more general term. Ductility is specifically about deformation without rupture under TENSION. Ductility is something for which you can specify a test, pick a unit, make a measurement, and get a number for. Ductility doesn't seem to have a precise universally agreed upon definition, so, at present, you do have to specify the test procedure, but usage universally recognizes that the response to TENSILE deformation is the essence, whereas plasticity is a more generic concept, not really subject to measurement.

Measuring?

Is there a standard system to measure ductillity?

No, "ductility" isn't quite as well defined as, for example, "density". There are several reasonably good types of tests, but no standard. The historical standard seems to be "how fine a wire can I draw from this stuff?" but that presumes a particular wire pulling technique. When you deviate from those historical techniques, you have to ask if you want "ductility" to mean a property of the substance or simply to reflect the state of the art of wire making. For example the claims for ductility of platinum higher than that of gold are based on a technique in which the platinum wire being drawn is supported and prevented from breaking by a silver coating so, in a sense, it's a cheat. And if that isn't an extreme enough example consider where 3d printing is heading. It should, in principle, be possible to make a wire 1 or 2 atoms thick out of pretty much any metal and a lot of non-metals, so if you don't assume a specific technique of fabrication & merely define ductility in terms of how fine a wire can be made, it loses any real utility as a word as new techniques are developed. See: https://www.physicsforums.com/threads/what-are-ductility-and-malleability.750473/ [unsigned]

Article says or implies ductility is expressed or measured as a percentage elongation before fracture under tension (or percentage area reduction at the neck). If that is accepted can we have a table of values ? Comments above say gold can be drawn to a single atom so the percentage elongation depends on the diameter you start with ? - Rod57 (talk) 17:18, 30 November 2019 (UTC)

Malleability measure

Article seems to regard malleability as how thin a sheet can be beaten or rolled. If this accepted, can we have a table of such thicknesses ? Zinc, bismuth and arsenic apparently are "not malleable". - Rod57 (talk) 17:18, 30 November 2019 (UTC)

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 09:48, 10 November 2007 (UTC)

Image

The image of the gold sheet shows malleability not ductility. Does anyone have an image showing ductility? Stephen B Streater (talk) 07:38, 16 May 2008 (UTC)

The current image should be removed then if it doesn't reflect ductility. Wizard191 (talk) 12:53, 16 May 2008 (UTC)

Just to illustrate the difference, these platinum cubes were manufactured by making thick square intersection bars and stretching them until they were 1cm by 1cm (and then slicing them to make cubes). This happened without them cracking because platinum is ductile. Stephen B Streater (talk) 18:45, 16 May 2008 (UTC)

So added the image with a description of that. You might also want to add why they were manufactured that way, as opposed to other methods. --Wizard191 (talk) 20:15, 16 May 2008 (UTC)

Done. Stephen B Streater (talk) 18:54, 17 May 2008 (UTC)

I don't think this photo of platinum cubes illustrates ductility very well. There should be some indication of deformation, such as necking in a tensile specimen. Sigmund (talk) 15:56, 19 May 2008 (UTC)

I disagree. Gold is very ductile, therefore it can be hammered into sub-micron thickness. Malleability is directly related to ductility and yield strength. Ductility and yield strength are quantifiable properties; malleability is not. Sigmund (talk) 15:56, 19 May 2008 (UTC)

The definitions I have seen say ductility is about stretching, and malleability is about hammering into thin sheets. So the fact you can hammer gold shows it is malleable, not ductile. Ideally, we would have an image of something being stretched into a wire, but the question at the moment is whether this image is better than no image, as we don't have a more wiry one. Stephen B Streater (talk) 17:18, 19 May 2008 (UTC)

Your argument is not valid: Ductility does not exclude malleability. —Preceding unsigned comment added by Sigmund (talk • contribs) 14:14, 20 May 2008 (UTC)

So perhaps merging the articles would be appropriate then. Ductility seems to be biased towards stretching, and malleability towards squashing, but they can both mean generally pliable. Stephen B Streater (talk) 15:25, 20 May 2008 (UTC)

I don't mind either way. The concept of malleability is historically important, but it doesn't see much use in modern materials science. —Preceding unsigned comment added by Sigmund (talk • contribs) 15:52, 20 May 2008 (UTC)

I disagree with the idea that malleability is only of historic importance, as the property is required when rolling sheet metal. However, I agree that it is rarely called malleability, and often referred to as ductility, in industry and educational institutions. --Wizard191 (talk) 16:03, 20 May 2008 (UTC)

Merge?

Seeing as ductility and malleability are easily confused as it is, merging the articles may make be even more confusing. Stephen B Streater (talk) 18:55, 17 May 2008 (UTC)

Not if the article is rewritten to clarify the point.Peterlewis (talk) 19:14, 17 May 2008 (UTC)

So would all (physical?) properties of eg metals be combined into one article? What would be the underlying rationale for a merge? Stephen B Streater (talk) 19:20, 17 May 2008 (UTC)

Not necessarily. Ductility and malleability are so closely related that they could easily be written up as though they were two aspects of one phenomenon, the ductility of metals. The the article could discuss the reasons: low slip forces, mobile dislocations etc, as well as talking about applications. Peterlewis (talk) 19:39, 17 May 2008 (UTC)

I'm unconvinced it's an improvement, but not strongly opposed either. I suggest, if you want to do it, that you start by writing a new article called "Ductility and Malleability", and when it's done, redirect the other articles to there. In that way, we will never be without a complete set. Stephen B Streater (talk) 19:51, 17 May 2008 (UTC)

You sound better qualified and in any case it needs a sceptic to pare the arguments and description down to reality! Peterlewis (talk) 19:55, 17 May 2008 (UTC)

That's very kind from a distinguished author such as yourself. I think I'll look for some more information first from a materials science source, as the articles don't match up very well at the moment. The properties do mirror each other quite well, as you point out. Stephen B Streater (talk) 20:02, 17 May 2008 (UTC)

Are these distinct thing? I assumed they weren't. My exposure to materials science (focusing on metals) only mentioned ductility. Can anyone cite malleability being different? If so, how do you measure the ability to be drawn through a die as opposed to being flattened? I assume this extreme deformation is well outside of simple models of material properties used in fracture-mechanics? —Ben FrantzDale (talk) 20:07, 20 May 2008 (UTC)

According to my materials and processes book (Degarmo), ductility is mentioned throughout (to describe the amount of plastic deformation a material can endure before "failure"), but malleability is only mentioned once. And when it was mentioned it was lumped with "workability" and "formability" to describe how suitable a material is for plastic deformation processing. I read that as there is a technical difference between malleability and ductility, which is that malleability actually references a process (flattening), but that it is just a subset of ductility. As such, I think the articles should be merged, with a paragraph explaining the slight difference. --Wizard191 (talk) 21:23, 22 May 2008 (UTC)

Just to point out that this article is not just about metals. In structural geology the term ductile is used to describe any deformation of rocks to large strains that occurs without significant fracturing and brittle faulting, regardless of the deformation geometry. By all means merge the articles, just don't make the definition for ductile too narrow. Mikenorton (talk) 20:53, 24 May 2008 (UTC)

Ductility's Proper Definition

In science class I was taught that ductility is the ability of a material to be stretched into wires, whereas malleability is the ability of a material to be shaped. The currently given definition of "a mechanical property used to describe the extent to which materials can be deformed plastically without fracture." seems to fit better with malleability. I think that the "stretched into wires" part is key for the definition.24.83.148.131 (talk) 15:02, 1 September 2008 (UTC)BeeCier

The articles definition for ductility is consistent with the field of materials science and engineering.The Lamb of God (talk) 01:17, 1 December 2009idea (obviouslyC)

Who gave material scientists and engineers the authority to change the meanings of words that already had practical definitions? I grant that such individuals are very qualified to do what they do: but they are not qualified to be linguistic prescriptionists. At ANY rate, as it stands, the article states that platinum is the most ductile metal but gold the most malleable. IF this is true, then malleability and ductility CANNOT be one-and-the-same. Not within any reasonable definition - if one wanted to go to extreme lengths, every single thing that exists could be reduced into only a handful of fundamental cosmologic categories - this would not a good idea (obviously). Firejuggler86 (talk) 22:43, 25 November 2020 (UTC)

Is gold the most ductile?

I checked out the source for the claim that gold is the most ductile metal, and the book clearly is ranking metals used in sculpture, NOT all metals. http://books.google.com/books?id=hW13qhOFa7gC&pg=RA1-PA129&vq=most+malleable&source=gbs_search_r&cad=1_1 How is it that gold is more malleable and ductile than any of the alkali metals? I think if this "fact" remains in the article, it should be clarified. If there is no disagreement about this, I will make the necessary change. Brittlandk (talk) 19:15, 14 February 2009 (UTC)

I was the one who added that reference. It was the closest thing I could find to a listing of the most ductile metals. However, I also found this source which backs it up: http://books.google.com/books?id=4hbhBsRAOAoC&pg=PA410&lpg=PA410&dq=list+of+most+ductile\+metals&source=web&ots=MXkhtdT3cs&sig=n1YvGNaguoWqD9aeyXeRzMxfptQ&hl=en&ei=pIKYSd6NFYLqNIisnIMM&sa=X&oi=book_result&resnum=8&ct=result. If you can find a different reference that backs up your point, I'm all for it. Wizard191 (talk) 21:06, 15 February 2009 (UTC)

Lead

There appears to be a contradiction between the statement early in the article that "lead is only malleable [not ductile]" and the placement, one screen later, of lead in the list of ten "most ductile metals" (albeit at the end). Maybe that is the complete list of metals from that source and lead, being at the end, is supposed to have zero ductility. But in that case the phrasing "most ductile metals" should be changed. Derek1G (talk) 06:21, 2 March 2009 (UTC)

I see what you are saying. I looked up the ref to the list and have modified it accordingly. Let me know what you think. Wizard191 (talk) 12:48, 2 March 2009 (UTC)

I disagree completely with the statement that lead is only malleable and not ductile. When loaded in tension, lead stretches (and necks down) prior to rupture. This is ductility. A stress strain curve for pure lead is shown here: http://books.google.ca/books?id=up5KS9fd_pkC&pg=PT804&lpg=PT804&dq=lead+stress+strain+curve&source=bl&ots=exgSmMEibw&sig=Vk5R-b6NbgU0CyZDxPE0wNofJ6I&hl=en&ei=RkrpStWQMZa9jAeFqoHHAg&sa=X&oi=book_result&ct=result&resnum=6&ved=0CCUQ6AEwBQ#v=onepage&q=lead%20stress%20strain%20curve&f=false

I recommend this statement be removed. Lead is both ductile and malleable. Quoting a reference on sculpting when the article is about materials science is not appropriate, either. —Preceding unsigned comment added by 195.220.252.125 (talk) 08:20, 29 October 2009 (UTC)

interwiki

Please, fix interwiki list. The list contains double link on the same wikis, for examle, double link to pl, de, and simple --Dnikitin (talk) 06:28, 13 September 2009 (UTC)

Easier said than done. As far as I can tell, I can only understand some of the languages, the double links have arisen because of the merger of the ductility and malleability pages, in the other wikis these are still treated as separate articles. Therefore, the double links are correct, if admittedly confusing. So the only 'fix' available is to either separate the two articles again here or to merge all those in the other languages. Mikenorton (talk) 10:58, 13 September 2009 (UTC)

Simple.wikipedia.org

simple:Ductility
simple:Malleability
As seen in the "in other languages" box on the left. Which will it be? 77.249.229.249 (talk) 20:10, 12 January 2010 (UTC)

Both, since this article is about both. Wizard191 (talk) 20:58, 12 January 2010 (UTC)

Ductility of mercury

What about Mercury? Is it infinitly ductile or does it come under a different sort of system because it is a liquid metal @ STP? —Preceding unsigned comment added by Cybergothiche (talk • contribs) 15:03, 24 July 2010 (UTC)

Ductility is a property for solids, therefore it doesn't apply to liquids nor mercury at STP. Wizard191 (talk) 15:11, 24 July 2010 (UTC)

Is there any accessible published work on the physical properties of solid mercury? Roger (talk) 07:57, 15 June 2011 (UTC)

References that are unreliable, better books to replace them

The reference used in the wikipedia article to claim that iron is more malleable than platinum or copper is a book ("The Materials and Methods of Sculpture", description on http://books.google.fr/books?id=hW13qhOFa7gC&hl=fr , written by an ARTIST who compiles data and interprets them accordingly to his background . It is not worth much. When reading materials handbooks destined to be used by design engineers working in the industry, books such as "Materials Handbook" by McGraw-Hill, 15th edition, 2002, are much more valuable http://www.mhprofessional.com/product.php?isbn=007136076X . In the entry "platinum" for example, it is explained that platinum is more ductile than gold (hence platinum is the most ductile metal) and in the "gold" entry, it is explained that gold is the most malleable of metals.

I erased the paragraph comprising "lists" that were posted in the article, they were not reliable and contradict all the data available in engineering books. Other engineering data books would be of better use for future reference instead of "art" books.

Another book which confirms the non-validity of the art book cited before is the "CRC encyclopedia of materials parts and finishes,second edition by M.Schwartz, 2002" http://www.crcpress.com/product/isbn/9781566766616 . M.Schwartz isn't a nobody, he's the editor of the "Advanced Materials Journal". His book, in the entries "gold" and "platinum" confirms that: -gold is the most malleable metal -platinum is the most ductile metal 82.240.163.245 (talk) 14:44, 25 December 2011 (UTC)

More: the ordered "list" of ductile metals in decreasing order, which is still on the wikipedia article for "ductility" , is the same as can be found in the book "Elements of Chemistry: theoretical and practical, Volume 2" by William Allen Miller. The problem is that this book is from ... 1864!!!! (link:http://books.google.fr/books?id=DBZDAAAAIAAJ&pg=PA318&dq=ductility+of+metals&hl=fr&sa=X&ei=TrAET5_0K4X-8gPF2Mi2AQ&ved=0CE0Q6AEwBTgK#v=onepage&q=ductility%20&f=false) Pure platinum wasn't available at the time and was still relatively hard due to it's impurities from the platinum group, nowadays, such "lists" have changed quite a lot. The element beryllium had been discovered only a few years before (in 1828). Time to uptade age old lists here on wikipedia, guys. Not that I would like beryllium to be mentioned or listed, it's very brittle, it's a simple remark to show that 1864 is a bit old as a references and many art books rely on mouth to ear "scientific" properties of materials,properties which are sometimes urban myths or thought to be true by the scientific community at the time (for example in this materials' properties book from 1864) but now proven wrong. 82.240.163.245 (talk) 20:21, 4 January 2012 (UTC)

units of Ductility and Malleability

Repeating robbiemuffin's request for units of malleabilty and ductility to be included in this article. http://www.engineersedge.com/material_science/ductility.htm uses "Percentage of Elongation after fracture" and "Percentage reduction in Area at fracture". Is maleability "the ratio of max achievable surface area/volume"? Or more simply the thickness of the thinnest coherent stable sheet formable from the material using stamping or hammering. Also requesting the creating of 2 articles like http://en.wikipedia.org/wiki/List_of_thermal_conductivities so http://en.wikipedia.org/wiki/List_of_Maleabilities_of_Substances and http://en.wikipedia.org/wiki/List_of_Ductilitiesies_of_Substances 124.170.2.66 (talk) 00:10, 12 February 2012 (UTC)

I think you could easily understand that malleability is NOT "the ratio of max achievable surface area/volume" with "achievable" being the equivalent of "by any means, methods". By electrodeposition, CVD,plasma beam deposition , ion beam deposition, etc you can create extremely thin atomic sized layers on a substrate. Malleabilty is all about hammering and stamping for example , in other terms purely mechanical forces are applied .Rolling into a sheet with a rolling mill could do the trick , it is a method used industrially, see "goldbeating" on wikipedia. 82.240.163.245 (talk) 05:56, 20 February 2012 (UTC)

Lists

Both the requested lists seem to have strange spellings - Maybe have : List_of_Malleabilities_of_Substances and List_of_Ductilities_of_Substances or even List_of_Malleabilities and List_of_Ductilities - Rod57 (talk) 17:52, 30 November 2019 (UTC)

Brittle nodular cast iron??

Is this picture really nodular cast iron? Cast iron is brittle, but nodular cast iron should have higher ductiliy.

--Eio (talk) 10:33, 9 January 2015 (UTC)

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Opening section

The opening section of the article was a bit of a mess so I replaced it with a more general and cohesive summary on the subject of ductility. I thing some of the content previously included in this section (e.g. the formulas on percent elongation) is useful, but would be more suitably placed in different sections of the article.

BirdmanOfHorseradish (talk) 23:43, 14 November 2020 (UTC)