Making a welded Damascus Knife

John Neeman Tools have posted a beautiful video of manufacturing a welded Damascus patterned knife.

5 layers of 3 different steels were forge-welded, folded, and forged. With each step being repeated 8 times. This produces a patterned with 320 layers. Finally twisting and forging the steel produces a more complex pattern.

Just checking the number of layers, I get their total to be different. My calculation of the number of layers is 5 × 28 = 1280, that is 4 times more than claimed (320 layers should be the result of folding 6 times (6 folds 5 × 26).

With 1280 folds, if we assume the thickness of the knife is 2 mm, that means each layer is 1.6 μm, 320 folds would be 6 μm layers. These are both lower than what can be resolved using the naked eye. It’s very close to the wavelength of visble light — if the metal were folded one more time, or the final thickness of the knife is less than 1 mm you would be there.


Effect of tempering upon the tensile properties of a nanostructured bainitic steel

This paper is now available at for those with access by science direct. I made final proof corrections last Saturday, so when the final version is released the conclusions will change… in that “hard–nanostructured–bainitic steels” will become “hard nanostructured bainitic steels”.

M23 Vs M23C6

Can Metallurgy contribute to understanding of political geography? By analogy we have grain boundaries rather than national boundaries. In metallurgy, thermodynamics is the driving force depending on interaction between atoms, in politics the fundamental interaction is human-to-human. In both cases the details are complex, and difficult to determine. For atoms there is a fundamental theory which explains the interactions, the Schroedinger equation, but it can only be solved by using approximations. There is no fundamental equation for human-to-human interactions (it’s actually the same one but no one even proposed to solve it for such a complex system).

Back to the scale of grains and countries, national boundaries can move as larger countries absorb smaller countries which is the phenomenon of Otswald Ripening. National boundaries are often along geological features such as mountain ranges, there are pinning the boundaries.

In metallurgy we have new phases which nucleate, these usually form on grain boundaries since there regions are more disordered. Here we can see comparison of M23C6 carbide forming on a grain boundary in steel, to the political group M23 formed in the border region of congo.





Adventures in Physical Metallurgy of Steels

During July 2013 I attended Adventures in Physical Metallurgy of Steels hosted by the Phase Transformations and Complex Properties research group of the Department of Materials Science and Metallurgy.

The programme looked like this, videos are appearing on bhadeshia123’s channel on youtube (links). There is also a playlist available.

Introduction to Adventure. H. Bhadeshia

Architectured Steels, T. Koseki

Magneto-structural coupling. I. Abrikosov

Quench and partitioning. J. Speer

Crystallographic variant selection. S. Kundu

Secondary hardened bainite, J. R. Yang

Welding of high carbon steel, K. Fang

Isotropy and Fatigue: P. Ölund

Atoms in bainite, atomic mechanisms. F. Caballero

Pulsed steels, R. Qin

Fullerenes & buckyballs in steel: I. V. Shchetinin

Boron: Type IV cracking, F. Abe

Low-density steel, H-L. Yi

Friction stirring of steel, T. Debroy

Flash Processing, G. Cola

Reliable first principles calculations for iron: A. Paxton

Steels composites for energy applications, C. Capdevila-Montes

Microstructures without contact, C. Davis

Pop-in deformation, H. N. Han

Plausibility of fine bainite, C. García-Mateo

Reduced Activation, K. Wu

Architectured microstructures, G. Anand

Flash microstructure, S. Babu

Energetic TWIP, D. Dye

Mass production of fine bainite: A. Rose

Voids and 30000 atoms, S. Munetoh

Soft Particles, T. Tsuchiyama

Mechanochemistry, F. Miani

Simplex and Kappa steels, I. Gutierrez-Urrutia

Innoculated high-speed steel, A. Chaus

Non-cubic ferrite, D-W. Suh

Montage of events

Fictional Materials: Vibranium alloy

An alloy of ‘Vibranium’ and steel created by accident, this industructable alloy was only made once, in the shape of a test piece which was then presented to Captain America to use as a shield. The indestructible nature of the alloy means it is not possible to characterise. Attempts to recreate the conditions of the alloy lead to the development of Adamantium. The nearly indestructible alloy forcibly implanted into Wolverine.

Captain America

Captain America before he received his iconic round shield made from Verbranium. Without it he was only able to defeat Nazi’s.

Grain Boundary Allotriomorphic Ferrite and Polygonal Ferrite

Bodnar and Hansen (writing in 1994) note that Polygonal ferrite can occur as grain boundary allotriomophs and intragranular idiomorphs. They then demonstrated the similarity between grain boundary allotriomorph and polygonal ferrite  by showing the same grain boundary area at two different magnifications with different labels. In the combined image you can see that the arrow is pointing at very similar position in two figures.

Grain Boundary Allotriomorph in Figure 1 A





Polygonal Ferrite Figure 1 B

Polygonal Ferrite in Figure 1 B


Posiiton of Figure A in Figure B

Posiiton of Figure A in Figure B