Tubaryan12 wrote:Hey Rick:
Titanium vs Stainless steel vs Brass - Please give us the hardness of all 3 and their ability to resist that nick on the rim that, of course, renders any mouthpiece unusable
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With titanium it depends significantly on the alloy.
Commercially Pure (CP) titanium is not that strong. Yield strength is 20,300 psi, and ultimate strength is 31,900 psi. Stiffness is 16,800 ksi (ksi = 1000 psi). Brinnell hardness is 60.
Mix a little aluminum and vanadium in it, though, and it gets strong in a hurry. 3Al2.5V titanium yields at 72,500 psi and breaks at 89,900 psi. Brinnell hardness is 256. But it's actually a bit less stiff with a modulus of elasticity of 14,900 ksi.
70-30 brass is less strong but more tough that CP titanium, with a yield strength of 14,000 psi and an ultimate strength of 44,500 psi. This is worked brass, not annealed, and I don't know how work-hardened it is. If you annealed it, it would be less strong but elongation at failure would be greater. It's about as hard as CP titanium, but much less hard than 3Al2.5V titanium alloy. Stiffness is very similar to titanium at 16,000 ksi.
Stainless steel also depends on alloy. Typical medical-grade stainless (Type 316) yields at 34,800 psi and breaks at 79,800 psi. It's much stiffer than titanium or brass, with a modulus of elasticity at 29,000 ksi. It's harder than brass and CP titanium, but not as hard (or as strong) as high-strength titanium alloys.
I don't know what Ivan uses--maybe he'll tell us.
From an acoustic point of view, all these materials are highly elastic below their yield strengths, so any notion of a mouthpiece damping vibration makes no sense to me. The mass of the mouthpiece might change it's resonance, though I can't see how that matters. But they all ring efficiently when you ring them like a bell.
Titanium is the lightest, at .163 pounds/cubic inch. Steel is heavier at .289 pounds/cubic inch. Brass is the densest at .308 pounds/cubic inch. Their specific stiffness varies, with titanium and steel being not that far different and brass being a little over half as stiff pound-for-pound. That means a heavy brass mouthpiece won't be as stiff as an equally heavy steel or titanium mouthpiece. A titanium mouthpiece that is the same weight as a steel mouthpiece will be about as stiff, but it will be a lot chunkier because it's only a little over half the density, and it could potentially be
very much stronger because of that chunkiness. It also means that when the pendulum swings the other way and the fad goes to ultralight mouthpieces, the titanium mouthpiece can be very light and still have adequate strength for durability, assuming the machinists can turn them down that thin. Titanium is the most difficult to machine of the three.
In terms of durability, the stainless steel will be best unless Ivan is using a high-strength titanium alloy.
Given that the mouthpiece's ring is fully damped by the gooey face pressed against it, I suspect that all of the differences between the materials would be mighty hard to quantify in any objective way. Overcoming placebo effect to study the results objectively would be a daunting challenge, but in music, placebo effect counts.
I personally like the feel and durability of stainless steel, and think the right alloy of titanium would do just as well. Steel feels like gold-plating on my lips.
Stainless steel and titanium are also the most inert of the options, and can really be scrubbed to keep them clean.
Rick "we report, you decide" Denney
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