Talk:Ductility

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 Love Grapes!

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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 17:02, 18 October 2005 (UTC)

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)

Measuring?

Is there a standard system to measure ductillity?

Brittle/ductile transition

It is not true that the brittle/ductile transition is a hard boundary. The position of the transition changes with strain rate, orientation of stress, pH2O (for rocks) and lots of other factors.

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