Technical guide · 2026-08-14
Molybdenum Alloys
Molybdenum combines high-temperature stiffness with lower density than tungsten, while TZM and lanthanum-doped systems improve recrystallization or creep behavior only when processing and grain structure are controlled.
01
Definition and boundary
Includes pure Mo, TZM and Mo-La; excludes molybdenum-bearing steel and nickel alloys.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Mo retains stiffness at heat.
Ti-Zr carbides strengthen TZM.
Lanthanum oxide stabilizes elongated grains.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| Pure molybdenum | General vacuum/inert high-temperature product. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
| TZM | Mo-Ti-Zr-C strengthened alloy. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
| Mo-La | Oxide-dispersed recrystallization-resistant system. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
04
Properties and trade-offs
Hot stiffness
Low thermal expansion
Rapid oxidation in air at elevated temperature
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Vacuum furnace parts
- Glass-melting electrodes
- Semiconductor hardware
Properties and trade-offs
- Define atmosphere first.
- Use TZM for load, not generic oxidation resistance.
- Specify grain direction for formed parts.
07
Fabrication, durability and inspection
Protect from oxidizing heat.
Use large bend radii by condition.
Qualify electron-beam, laser or brazed joints.
08
Procurement checklist
- State pure Mo, TZM or Mo-La.
- Define stress-relieved/recrystallized condition.
- Specify O/C impurities, grain direction and surface.
09
Standards, sources and review
Standards and designation context
- Applicable ASTM B10 product specification
- Buyer drawing and material condition
- Qualified joining and inspection procedure