Titanium-Molybdenum alloy?

[Jack Lewis]

Hi guys,

Forgive me if this has been discussed -- I had a look around and couldn't find it. I'm looking for information on the viability of titanium-molybdenum alloys (known some places as TMA) as a blade material. It seems to have all the characteristics of a fantastic candidate, but maybe I'm overlooking something. Of maybe cost is the issue?

As a secondary question: I'm trying to sort out what happens when there's too much molybdenum in a metal. I'm not seeing any of the downsides you might see with vanadium, for instance, but I'm also unable to find examples of alloys containing more than about 4 percent molybdenum. Does it get brittle at higher amounts? Soft? Expensive?

I appreciate any help, pointers, suggestions, advice, cussing or discussing --

Thanks!

 

[The Mastiff]

The Moly ( M-series) High speed steels get much higher amounts of moly. http://www.sousacorp.com/ts-comp.htm#MOLYBDENUM%20HOT%20WORK%20TOOL%20STEEL

I see moly percentages as high as 8.50%. Edit: 10.50% in M62 ( Aka REX 20 from Crucible "rex" line), in a class called "ultrahard high speed steels". In these steels the moly is essentially a tungsten ( more expensive ? ) replacement ( and Cobalt replacement in M62) and gives "red hardness" meaning it doesn't loose hardness at higher temps and can be used at higher speeds on the line. etc. That's a rough outline and more can be found be reading about the different steels, classes, and effects of elements and combinations.

I have read that the moly carbide is similar in size and hardness to the tungsten carbide ( both smaller and softer than vanadium, but harder and more wear resistant than chrome carbides.

Moly at lower amounts are used for different purposes that would probably be better explained by someone more knowledgeable than me.

I don't know about Titanium as a carbide former in steels. My main interest is cutlery steels so that may be why.

Joe

 

[Jack Lewis]

Hey, thanks for the response, Joe.

And thank you for the link. Sounds like Molybdenum is good stuff. I figure there must be a downside somewhere, or we'd see all-Moly blades. Any idea what happens when there's too much in the mix?

 

[james terrio]

An all-moly blade would be awfully expensive, for one thing. Moly, in addition to forming carbides, is used mainly to increase steel's hardenability and as Mastiff mentioned, maintaining hardness at high temperatures.

 

[all 41 + 14 all]

My Google results suggest that roughly 2% Moly acts to stabilize beta phase Ti. Perhaps the OP is simply referring to Beta Titanium?