Multi-alloy titanium katana and titanium miao dao

[Mecha]

Hello again,

Here is a sword from last summer you might like to see.

It is a katana blade made from three different titanium alloys, with a springy spine, hardened edge, and a "hamon" weld. The billet was first welded, then forged. Then ground, hardened, and ground some more. Finally, it was mounted in shirasaya, with a silver habaki and seppa.

Video:

Next is a titanium miao dao. This one was forged from 90Ti 10Nb bar stock, hardened, and mounted in a reinforced shirasaya suitable for cutting use. Tsuba is also titanium alloy.

Thanks for looking! :]

 

[yaammoo]

Hey Mecha,

you bet that we want to see those extraordinary works of yours. Thank you very, very much for sharing. Do you want to explain how you welded, forged etc. the alloys? Do you have pictures of the different processing steps?

Greeting

yaammoo

 

[Geonohl]

Gorgeous, to see that made from titanium.
Is the third thin colour in the “hamon weld” an migration area of alloy elements?
Is it to the volume of historical swords and therefore lighter or did you make it bigger?

 

[Mecha]

Glad you like the sword!

For the layered sword, the "hamon" is a TIG/GTAW weld, between the spine alloy and the edge alloy which is more hardenable. The visible line is the filler rod that was welded between the two before forging and grinding.

The hardened edge is Russian BT23 armor plate alloy, and the spine is 6al4v common titanium alloy.

The BT23 gets hard, low to mid 50s HRc, while the spine is an alloy that is extremely resistant to crack propagation. The weld is in between the two. So the blade has a real trimetallic effect going for it.

The miao dao is pure 90 Ti 10 Nb alloy, which is a shallow-hardening alloy akin to high carbon steel like 1095. Soft in the core, hard on the surface to a depth of about 1/16" or so.

Lately I've made forge-welded san mai three-layer swords of titanium, with tough cladding over a hard core. I'll post them when completed.

 

[Geonohl]

Yes, your blades are really astounding.
Now I see a surface structure on the TSUBA.
Did you etch it before cutting it out?

 

[yaammoo]

Mecha,

thank you for your explanations. I am curious about your forge-welded san mai three-layer swords of titanium.

yaammoo

 

[Mecha]

Re: AW: Multi-alloy titanium katana and titanium miao dao

Yes, your blades are really astounding.
Now I see a surface structure on the TSUBA.
Did you etch it before cutting it out?

Thank you!

That surface pattern is the natural surface of an ATI425 alloy plate that's been conditioned for use as ballistic armor, but has been sandblasted, then touched to a polishing belt. The armor plate iteration of that alloy is pretty rough, while the annealed pre-fabrication version is very smooth and flat.

 

[Mecha]

Re: AW: Multi-alloy titanium katana and titanium miao dao

Mecha,

thank you for your explanations. I am curious about your forge-welded san mai three-layer swords of titanium.

yaammoo

The san-mai billets are very laborious to make. About as complicated and difficult as it can get, in this endeavor of making ti alloy swords. In them, the core is of the best hardenable blade alloy, while the cladding is tougher stuff. It's also possible to make go-mai or hachi-mai, whatever is desired. I intend to explore layered billets further, but will need more heavy equipment.

Between the two, I secretly like the welded edge billets better, but due to difficulties making them and the dimensions of the alloys I've been able to get, they are more appropriate for smaller swords, while the san-mai can make really large blades.