Twins and Martensite

The development of improved metallic materials is a vital activity at the leading edge of science and technology. Metals offer unrivalled combinations of properties and reliability at a cost which is affordable. They are versatile because subtle changes in their microstructure can cause dramatic variations in their properties. For example, it is possible to buy commercial steel with a strength as low as 50 MPa or as high as 5500 MPa. They can be made with a microstructure which is finer than that of carbon nanotubes. An understanding of the development of microstructure in metals, rooted in thermodynamics, crystallography and kinetic phenomena is essential for the materials scientist. The majority of the 1.4 billion tonnes of metals produced annually are the result of developments within the last ten years
H. K. D. H. Bhadeshia
Producer: H. K. D. H. Bhadeshia
Cameraman: Brian Barber
Camerawoman: Carol Best

[@tunceris]

Thank you so much for this lecture. It was impossible to understand twinning from my local lectures , but here I got it in 5 mins. Thank you so much, again.

[@bhadeshia123]

You are welcome.

[@user-lk4ow6ej1e]

your lecture is really splendid, I adore it. And nearly all of my doubts have been removed. Thank you prof. Bhadeshia.

[@bhadeshia123]

Thank you.

[@user-yo1nd2lh3i]

I am also quite impressed by your lecture because so simlply you explained all the contents that students could understand hard. Anyway, I am so thanksful your lecture that you are sharing.

[@bhadeshia123]

Thank you.

[@wanghou6219]

Generally ,why material which deform by twin is brittle than material by slip?

[@bhadeshia123]

That may not be the case. TWIP steels are not brittle.

[@ahmedtaiforazeez399]

A great lecture

[@bhadeshia123]

Thank you!

[@G-HZhao]

can't be more grateful

[@bhadeshia123]

You are welcome.

[@yaribsuarez8725]

I didn't get why the sharp end shape for mechanical twin reduce strain energy :/ 10:23

[@bhadeshia123]

A twin involves a large shear, which pushes against the surroundings. The thin plate shape and sharp tip help minimise the strain energy as explained in kzbin.info/www/bejne/q4W1oJKJqqetmK8