Talk:Slip bands in metals

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Moving to Slip band

@BillClyne thanks to your edit now I can move the page to slip band as it contains fatigue and non fatigue slipping. I organised things a little bit, but feel free to do what you want FuzzyMagma (talk) 20:48, 15 November 2022 (UTC)

Copy editing

FuzzyMagma, the article needs some serious copy editing. The prose is very difficult to parse and somewhat ungrammatical. I often cannot make out what it is intended to mean, and I have some background in metallurgy, albeit from about 40 years ago, and at undergraduate level, so I am probably at roughly the level of your target demographic. If I am confused, you are not reaching your audience. Cheers, · · · Peter Southwood ^(talk): 05:05, 4 March 2023 (UTC)

@Pbsouthwood let me do that. I will remove the GA nomination for now. Do you mind if I ping you back to check before I reinstate the GA nomination? FuzzyMagma (talk) 10:07, 4 March 2023 (UTC)

FuzzyMagma, We can do that. Cheers, · · · Peter Southwood ^(talk): 12:13, 4 March 2023 (UTC)

Proposed merge of Shear band into Slip bands in metals

They overlap and can provide a succinct description of the phenomenon FuzzyMagma (talk) 12:00, 9 March 2023 (UTC)

@SSMG-ITALY, @Forbes72 and @Corvus Ferrum (who contributed significantly to the Shear band article), and @Pbsouthwood and @BillClyne .. I wonder if I can get your opinion on this FuzzyMagma (talk) 12:07, 9 March 2023 (UTC)

Adiabatic shear band may also be the same thing. This is a bit more than a stub but seems to be the same subject. I suggest and support a merge of all three. NeedsGlasses (talk) 23:09, 9 March 2023 (UTC)

I think the Shear band can form a very coherent start before jumping to the details of slip bands in metals including fatigue and tensile and “adiabatic” slip bands FuzzyMagma (talk) 08:42, 10 March 2023 (UTC)

• I have no objections at this point. Presumably with the original articles becoming redirects to sections of the combined article. What title would be used for the combined article? Cheers, · · · Peter Southwood ^(talk): 10:56, 10 March 2023 (UTC)

  @Forbes72 what you described at the beginning is called Persistent slip bands and the 2nd example is Slip bands in the absence of cyclic loading both covered in the Slip bands in metals article

  .

  Your statement “On the other hand, a shear bands are larger scale faults that are not directly tied to crystallography” is true (for later stages of deformation when there is large lattice distortion, Raabe p. 2298), which also describes Luder bands which depends primarily on the microscopic (i.e. average grain size and crystal structure) and Portevin–Le Chatelier effect.

  Which all just types of Slip bands in the absence of cyclic loading. The 2nd images at that section is for a “coherent/Schmid” slip or shear band becoming “non-coherent/Schmid” due to large lattice distortion.

  .

  Shear bands and slip bands are the same thing. Crystal slip in shear weather it is dictated by crystallography or load direction at later deformation stages. The transition from Slip to a shear band is similar to the transition from a micro-crack (that crystallography sensitive) to a macro crack (that is not). Dislocation to slip to slip line to slip or shear band .. see: https://doi.org/10.1016/0956-716X(94)90201-1, https://hal.inrae.fr/hal-03462444/document

  I will later add some references where the word Slip band and shear band used interchangeably

  .

  but I understand your point as you want to keep the micro scale description away from the macro, although the micro can also be non-crystallographic. Let’s keep discussing this FuzzyMagma (talk) 16:34, 10 March 2023 (UTC)

@FuzzyMagma: As I read the Slip bands in metals article, both persistent slip bands and slip bands in the absence of cyclic loading are contained in individual metal grains. They can transfer stress to an adjacent grain, but for example you can't have the same slip band in both the alpha and gamma phases, since a slip bands are closely tied to crystallographic defects, but alpha and gamma phases have different crystal structures. (so a dislocation defect has trouble traveling across a grain boundary) The Shear band article describes macroscopic experiments which are too large to represent the shear within an individual grain. The papers you cited also mention these issues. The first one talks about the crystal directions for slip bands "CSB's [coarse slip bands] are different from MSB's [macroscopic shear bands] in two ways: i) they appear before any obvious necking and load drop, and ii) they are aligned closely with a slip plane.". (Dao 1993) The other one makes a similar macro/meso distinction, with "slip lines" at meso and "shear bands" at macro.

It's probably not worth worrying about the exact terminology, but if we keep the mechanistic distinction between the macroscopic behavior and the microscopic slipping along crystal planes, we should be in good shape. 〈 Forbes₇₂ | Talk 〉 01:02, 11 March 2023 (UTC)

I will expand the two article and a sentence about the difference in scale and events at beginning using the ‘about’ template. Will also added to the disambiguation page for Slip .. FuzzyMagma (talk) 17:37, 14 May 2023 (UTC)

These are related subjects, but not exactly the same. In crystallography, a slip usually refers to a dislocation that happens along a particular crystalline direction (e.g. along the <111> lattice plane in face centered cubic metals). These are faults that happen within single grains (crystallites). On the other hand, a shear bands are larger scale faults that are not directly tied to crystallography.

Here's a paper talking about a slip bands in a single crystal material:

"Under fatigue, plastic strain localisation and accumulation tend to occur in crystalline materials,leading to the formation of microscopic slip bands. This phenomenon is known to cause macroscopic damage to materials [1], with a significant effect on their deformation behaviour [2] and the nucleation of fatigue cracks [3]. The slip bands are of a discrete nature and follow certain slip planes of the crystal lattice," Zhang, P.; et al. (2021). "Discrete crystal plasticity modelling of slip-controlled cyclic deformation and short crack growth under low cycle fatigue". International Journal of Fatigue. 145. Elsevier BV: 106095. doi:10.1016/j.ijfatigue.2020.106095. ISSN 0142-1123.

Compare this to a book talking about shear bands:

"Shear bands are mesoscopic band-like deformation inhomogeneities in middle and heavily deformed metallic alloys. They appear under oblique angles relative to the main deformation axis and can penetrate multiple crystals in the deformation structure. They are characterized by a mesoscopic orientation that does not match a distinct crystallographic direction, for instance that of a specific slip or twinning system" Raabe, Dierk (2014). "Recovery and Recrystallization: Phenomena, Physics, Models, Simulation". Physical Metallurgy. Elsevier. p. 2335. doi:10.1016/b978-0-444-53770-6.00023-x.

I think it would be better to keep them in separate articles, but if we do merge the distinction should be kept clear. 〈 Forbes₇₂ | Talk 〉