Schmid’s law

Schmid’s law

[@syedhasnainali8282]

Critical resolved shear stress is the minimum resolved shear stress required to produce slip (which in turn causes plastic deformation) in a crystal. We also know that the tensile stress at the onset of plastic deformation is called yield stress. From the relation of yield stress and CRSS we know that at least one property of the two must change on changing orientation or Schmid's factor. Schmid experimentally determined that the yield stress changes with the orientation of the slip plane w.r.t the tensile stress axis. This must mean that the CRSS is independent of the orientation or angle of slip plane w.r.t the stress axis and is constant for the specific material. This is known as Schmid's law.

[@NITian-]

I am very very very...... Thankful sir Amazing concept. ❤️❤️ Outstanding, the way of teaching 🙏🙏🙏🙏🙏❤️❤️

[@bronktug2446]

Wonderfully explained!

[@harikrishnan3112]

Hi Sir. I have 3 doubts 1.On what basis we can classify a MATERIAL as isotropic and anisotropic? 2.When we classify materials as isotropic and anisotropic does it mean that all the properties of that material are isotropic and anisotropic respectively? 3.Can a isotropic material have anisotropic property?

[@introductiontomaterialsscience]

1. Well, generally crystalline materials are expected to be anisotropic (because different crystallographic directions have different atomic arrangements) whereas amorphous materials are expected to be isotropic because all directions are statistically identical. 2. Materials are isotropic or anisotropic with respect to a given property. For example, cubic crystals are isotropic with respect to electrical conductivity but are anisotropic with respect to Young's modulus. 3. As answer to 2 shows, a material isotropic for a given property may be anisotropic for another property.

[@sunilugadi3653]

Sir, at 10:23, is it not contradicting the statement of " yield strength is a material property " ?

[@rajeshprasad101]

No, it is not a contradiction. A material property can be isotropic or anisotropic. For a single crystal yield strength becomes anisotropic material property, i.e., it depends upon the direction of loading.

[@johnrebeiro1066]

​@@rajeshprasad101 for isotropic material tau crss is variable ? is tau crss is principal shear stress ?

[@himabindu8185]

Thank you sir..very useful

[@benishasim]

Thank you so much

[@priyanshusinha1209]

Sir what will happen if our sample will not composed of a single crystal.If our sample will be pearlite what will happen??

[@Vickysahu0092]

Can we say that, As sigma y is anisotropic due to this fact single crystal is also anisotropic ?

[@introductiontomaterialsscience]

I will put it the other way round. Yield stress in different directions of a single crystal is different. So a single crystal is anisotropic for yield stress.

[@samndf24]

@@introductiontomaterialsscience So Sir, Schmid's law is true for polycrystalline material as well but since we have many crystals oriented in different directions we get more or less the same yield stress values i.e isotropy and only appreciable changes can be seen when the surfaces are textured (like in rolling). Am I right sir?

[@introductiontomaterialsscience]

@@samndf24 You are right.

[@Rycamcam]

Thank you sir

[@KaranKumar-yg2gs]

Reference for Schmid's law?

[@introductiontomaterialsscience]

You can look up Mechanical Metallurgy by G.E. Dieter. The following website may also be useful: www.doitpoms.ac.uk/tlplib/slip/slip_geometry.php

[@benishasim]

Thank you so much