Refractory Metal TZM · heat-treated state
Refractory Metal TZM Vacuum Annealed
Properties of the Vacuum Annealed condition, compared with the other TZM tempers.
Choose when maximum dimensional stability and creep resistance above 1400 °C matter more than room-temperature strength; more brittle at RT because DBTT rises.
What is TZM Vacuum Annealed?
TZM Vacuum Annealed is TZM heat treated to Vacuum Annealed — choose when maximum dimensional stability and creep resistance above 1400 °C matter more than room-temperature strength; more brittle at RT because DBTT rises. TZM Vacuum Annealed has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 65% of refractory metal grades. Elongation at break is 25% and the elastic modulus is 315 GPa (45.7 Msi). TZM Vacuum Annealed has a density of 10.22 g/cm³ (0.369 lb/in³), heavier than 67% of refractory metal grades. It melts at 2,617°C (4,743 °F). Stress Relieved is the default condition FabDigit quotes; Vacuum Annealed is available on request or by drawing note.
Advantages
- Easy to machine — 50/100, better than 101% of refractory metal grades
- High service temperature — 1,500°C (2,732 °F), better than 85% of refractory metal grades
- Conducts heat well — 126 W/m·K (72.8 BTU/hr·ft·°F), better than 85% of refractory metal grades
- High electrical conductivity — 30 % IACS, better than 84% of refractory metal grades
- Stiff — 315 GPa (45.7 Msi), better than 76% of refractory metal grades
Limitations
- Needs corrosion protection — 45/100, worse than 87% of refractory metal grades
- Difficult to weld — 20/100, worse than 79% of refractory metal grades
TZM Vacuum Annealed properties
Typical room-temperature values for TZM Vacuum Annealed — 12 properties are specific to this condition; the rest are grade-level values shared by every TZM temper. Each bar shows where the value sits among the refractory metal grades in FabDigit's library — further right is higher.
Physical3
TZM Vacuum Annealed has a density of 10.22 g/cm³ (0.369 lb/in³), heavier than 67% of refractory metal grades. It melts at 2,617°C (4,743 °F).
Mechanical16
TZM Vacuum Annealed has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 65% of refractory metal grades. Elongation at break is 25% and the elastic modulus is 315 GPa (45.7 Msi).
Thermal6
TZM Vacuum Annealed is rated for continuous service to 1,500°C (2,732 °F). It conducts heat at 126 W/m·K (72.8 BTU/hr·ft·°F), better than 85% of refractory metal grades. Thermal expansion is 5.3 µm/m·K (2.94 µin/in·°F).
Electrical3
TZM Vacuum Annealed conducts electricity at 30 % IACS, better than 84% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 87% of refractory metal grades.
Sustainability4
Producing a kilogram of TZM Vacuum Annealed takes about 380 MJ of energy and emits 26 kg of CO₂ — less than 77% of refractory metal grades. Typical recycled content is 25%.
Manufacturability7
TZM Vacuum Annealed's machinability is fair (50/100, better than 101% of refractory metal grades); weldability poor (20/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other TZM tempers and conditions
TZM is also supplied in 4 other conditions. The full side-by-side table is on the TZM overview.
- Stress RelievedDefaultStandard stocked condition for rod, plate and forgings — best combination of room-temperature strength, ductility and dimensional stability up to ~1300 °C.760 MPa yield · 26 HRC
- Cold WorkedHighest room-temperature strength and hardness (thin sheet, wire, small rod); limited ductility and residual stress, not for service above ~1000 °C.940 MPa yield · 31 HRC
- Vacuum AnnealedChoose when maximum dimensional stability and creep resistance above 1400 °C matter more than room-temperature strength; more brittle at RT because DBTT rises.420 MPa yield · 12 HRC
Working with TZM Vacuum Annealed
Is TZM easy to machine?
Machines like a hard, abrasive cast iron — sharp positive-rake carbide or PCD tools, rigid setup, generous coolant, avoid dull edges that cause chipping and subsurface cracks; grinding and EDM work well.
Can TZM be welded?
Fusion welding (EB, laser, GTAW in chamber) recrystallizes and embrittles the joint — prefer vacuum brazing, mechanical fastening or friction/diffusion bonding for structural parts.
Can TZM be formed, bent or molded?
Form warm (200–500 °C, higher for recrystallized stock) to stay above the DBTT; generous bend radii, no sharp cold bends, and stress relieve at 900–1100 °C after heavy work.
What surface finishes work on TZM?
Cannot be anodized; use electropolishing or mechanical polish for clean vacuum surfaces and Si-Cr-Fe silicide, aluminide or CVD coatings when the part must see air above ~500 °C.
TZM chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Ticarbide former, main strengthener | 0.4 – 0.55 | 0.5 |
| Zr | 0.06 – 0.12 | 0.08 |
| Cforms TiC/ZrC dispersoids | 0.01 – 0.04 | 0.03 |
| O | ≤ 0.03 | — |
| N | ≤ 0 | — |
| Fe | ≤ 0.01 | — |
| Ni | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| Mobalance, ≥99.2 % with additions | balance | — |
TZM Vacuum Annealed — frequently asked
What is TZM Vacuum Annealed used for?
TZM Vacuum Annealed is typically used for rocket nozzles and thrust chamber inserts, hot-work extrusion and forging dies, furnace hot-zone structures and fixtures, die-casting core pins and shot sleeves, isothermal forging tooling and X-ray rotating anode substrates. In short: higher-strength molybdenum alloy.
What is the yield strength of TZM Vacuum Annealed?
TZM Vacuum Annealed has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 65% of refractory metal grades. Strength varies by condition: see the 5 listed tempers.
Is TZM Vacuum Annealed easy to machine?
Reasonably — machinability is rated fair (50/100, better than 101% of refractory metal grades). Machines like a hard, abrasive cast iron — sharp positive-rake carbide or PCD tools, rigid setup, generous coolant, avoid dull edges that cause chipping and subsurface cracks; grinding and EDM work well.
Can TZM Vacuum Annealed be welded?
Not readily — weldability is rated poor (20/100). Fusion welding (EB, laser, GTAW in chamber) recrystallizes and embrittles the joint — prefer vacuum brazing, mechanical fastening or friction/diffusion bonding for structural parts.
What surface finishes work on TZM Vacuum Annealed?
Cannot be anodized; use electropolishing or mechanical polish for clean vacuum surfaces and Si-Cr-Fe silicide, aluminide or CVD coatings when the part must see air above ~500 °C.
Can TZM Vacuum Annealed be formed, bent or molded?
Form warm (200–500 °C, higher for recrystallized stock) to stay above the DBTT; generous bend radii, no sharp cold bends, and stress relieve at 900–1100 °C after heavy work.
What is the maximum service temperature of TZM Vacuum Annealed?
TZM Vacuum Annealed is rated for continuous use to about 1,500°C (2,732 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in TZM Vacuum Annealed?
Yes — TZM Vacuum Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B387 — Molybdenum and Molybdenum Alloy Bar, Rod, and Wire (Type 364 TZM) — ASTM International (2018)
- ASTM B386 — Molybdenum and Molybdenum Alloy Plate, Sheet, Strip, Foil — ASTM International (2018)
- TZM molybdenum alloy material properties — Plansee SE (2023)
- ASM Handbook Vol. 2 — Properties of Refractory Metals and Alloys — ASM International (1990)
- Molybdenum and TZM technical data — H.C. Starck Solutions / Ed Fagan Inc. (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.