When to pay for titanium (and when aluminum or steel is wiser).

Titanium has a specific combination of properties that other materials don't match:

• Strength-to-weight ratio: Ti-6Al-4V tensile strength is 1,070 MPa at density 4.43 g/cm³. Per gram, it's stronger than most steel and all aluminum.
• Corrosion resistance: titanium forms a self-healing oxide layer that resists seawater, most acids, body fluids, and chlorine. Better than 316 stainless in most chemistry.
• Biocompatibility: titanium integrates with bone (osseointegration). Used in dental implants, hip stems, surgical instruments. FDA-cleared grades are the standard.
• High-temperature strength: Ti64 retains strength to 350°C continuous. Higher grades (Ti-6Al-2Sn-4Zr-2Mo) go to 500°C+.
• Low thermal expansion: half of aluminum's CTE. Useful in precision structures with other low-CTE materials.
• Non-magnetic: suitable for MRI-compatible medical devices and magnetic-sensitive scientific equipment.

Common patterns where titanium costs more than it's worth:

• Structural brackets in non-critical applications: 6061-T6 aluminum does the job for 1/15 the cost. Titanium brackets appear on hobbyist drone builds and non-flight consumer products — often marketing rather than engineering choice.
• Consumer EDC (everyday carry) items: knives, pens, watch backs. Stainless or high-carbon steel work fine mechanically. Titanium is a marketing proposition.
• Fasteners with low load: titanium bolts for small assemblies. Steel fasteners work; the weight savings rarely justify the cost beyond aerospace.
• Parts in dry environments: if the service environment doesn't attack stainless 316, you don't need titanium's corrosion resistance. You're paying for a property you don't use.
• Parts that don't need biocompatibility: for medical devices that don't contact patient tissue (equipment housings, brackets), medical-grade stainless is FDA-accepted and far cheaper.

Most structural and medical work uses Gr5 (Ti-6Al-4V). Gr2 for chemical and heat-exchanger applications where strength isn't critical. Gr23 ELI only when implant certification requires it.

Titanium is 3-5× the per-hour machining cost of aluminum at the same quality level:

• Cutting speeds 30-50 SFM (vs 500+ for aluminum)
• Tool life 1/4 to 1/10 of same part in aluminum
• Flood coolant mandatory (fire risk with chip buildup)
• Requires rigid setups — titanium springs more than steel
• Work-hardens at the cut edge

For a simple bracket taking 5 minutes in aluminum, expect 20-30 minutes in titanium. Combined with the 10-15× higher material cost, titanium parts often end up 15-25× more expensive than aluminum equivalents.