A practical engineer's guide to material selection beyond the spec sheet
The Real Cost Gap
Let's get the numbers out of the way first.
At Alloyer, we machine both materials daily. Here's what you can expect for a typical small-to-medium part (roughly 50?50?25mm):
| Material | Raw Material Cost | Machining Cost | Total Part Cost |
|---|---|---|---|
| 6061-T6 Aluminum | -12/kg | Baseline (1x) | -40/part |
| Ti-6Al-4V Titanium | -120/kg | 1.5-2x (slower feeds/speeds) | -140/part |
Bottom line: Titanium typically costs 2.5-3.5x what you'd pay for aluminum.
The question isn't whether titanium is better??t usually is. The question is whether your application justifies the premium.
When Aluminum is Good Enough (And It Usually Is)
About 80% of the parts we machine at Alloyer are aluminum. Here's why:
Strength-to-Weight That Gets the Job Done
6061-T6 offers:
- Density: 2.7 g/cm? (vs titanium's 4.5 g/cm?)
- Yield strength: 276 MPa
- Machinability: Excellent (we can run high feeds and speeds)
For most robotics brackets, drone frames, and electronic enclosures, that's plenty. If your part isn't seeing extreme temperatures or corrosive environments, aluminum is probably your answer.
The Prototyping Sweet Spot
When you're on iteration #3 of a new design and the geometry keeps changing, aluminum lets you:
- Get parts in 5-7 days
- Make design tweaks without crying about material costs
- Validate your fit and function before committing to exotic materials
When Titanium is Non-Negotiable
That other 20%? Those are the parts where choosing aluminum would be a mistake you'd regret in the field.
1. Medical Implants and Surgical Tools
Biocompatibility isn't negotiable. Ti-6Al-4V is:
- Biocompatible (ASTM F136 standard)
- Osseointegrating (bone bonds to it)
- Non-ferromagnetic (MRI-safe)
We machine titanium fixtures for surgical robots where a failure isn't just expensive??t's dangerous. No aluminum substitution possible.
2. Aerospace Structural Components
At 35,000 feet, material properties matter.
Titanium's advantages:
- Fatigue resistance: Maintains strength over millions of cycles
- Creep resistance: Won't deform under sustained load at temperature
- Corrosion resistance: No galvanic issues with carbon fiber composites
We see titanium in UAV airframes, satellite components, and high-performance drone mounts where every gram matters??ut only when aluminum can't survive the mission profile.
3. High-Temperature Applications
Aluminum starts losing strength around 150?C. Titanium? It keeps going past 400?C.
Exhaust components, high-temp fixtures, and parts near engines??itanium is the only practical choice.
4. Chemical and Marine Environments
316 stainless is corrosion-resistant. Titanium is essentially corrosion-proof.
Marine hardware, chemical processing equipment, and parts exposed to salt spray for years??itanium outlasts everything else.
The Hidden Cost of Choosing Wrong
Here's what doesn't show up in the BOM:
The Redesign Tax
We had a client specify aluminum for a robotic arm joint that saw cyclic loading. Six months after deployment, cracks appeared. The redesign in titanium cost:
- New tooling: ,400
- Engineering time: 80 hours
- Delayed product launch: 6 weeks
Total cost of "saving" on material: ~,000.
The Field Failure Cost
A medical device company used aluminum for a surgical guide that needed autoclave sterilization (134?C steam). After 50 cycles, the part warped out of tolerance. Switching to titanium fixed it??ut not before a recall and regulatory filing.
Quick Decision Matrix
| Application | Recommended Material | Why |
|---|---|---|
| Drone frame (non-structural) | 6061-T6 | Weight savings, cost-effective |
| Drone motor mount (high vibration) | Ti-6Al-4V | Fatigue resistance |
| Robotic arm (light duty) | 6061-T6 | Cost, machinability |
| Robotic arm (joint/transmission) | Ti-6Al-4V | Strength, wear resistance |
| Medical implant | Ti-6Al-4V | Biocompatibility only |
| Surgical tool (reusable) | Ti-6Al-4V | Autoclave compatibility |
| Electronics enclosure | 6061-T6 | EMI shielding, cost |
| Heat sink (high temp) | Ti-6Al-4V | Thermal stability |
| Marine hardware | Ti-6Al-4V or 316 SS | Corrosion resistance |
| Prototype (iterating design) | 6061-T6 | Fast, cheap iterations |
Machining Considerations
If you do choose titanium, know what you're getting into:
Tool Wear
Titanium work-hardens as you cut it. Carbide tools last maybe 20-30% as long as they do on aluminum. This drives up machining costs.
Speed Limits
We run titanium at roughly 40-50% of the surface speed we'd use for aluminum. The part takes longer to machine.
Chip Control
Titanium chips are razor-sharp and tend to weld to tooling. Proper coolant and chip evacuation are critical.
At Alloyer, we have dedicated titanium workflows??eparate tooling, adjusted feeds/speeds, and post-machining inspection protocols. Not every shop is set up for this, which is why titanium quotes vary widely.
The Verdict
Choose aluminum when: You're prototyping, the loads are moderate, temperatures stay below 150?C, and you need parts fast and affordable.
Choose titanium when: Biocompatibility is required, you're in high-temp or corrosive environments, fatigue life is critical, or the cost of failure exceeds the material premium.
The 3x cost isn't just about the material??t's insurance against the scenarios where aluminum fails.
Get a Quote for Either
Upload your STEP file to alloyer.com/pages/quote and we'll quote both materials. Our AI DFM analysis will flag potential issues with either choice, and our engineers review complex parts within 24 hours.
Questions about material selection? Chat with our Engineering Bot or email us at support@alloyer.com.
Alloyer Engineering Team
Published: April 26, 2026