Refractory Metal TZM Stress Relieved
Heat-treated state · default condition
UNS R03640, R03630 · ASTM B387 Grade 363 · also Mo-Ti-Zr
Standard stocked condition for rod, plate and forgings — best combination of room-temperature strength, ductility and dimensional stability up to ~1300 °C.
Values for the Stress Relieved condition
Other TZM tempers and conditions
TZM is listed in 5 conditions; see the grade overview at TZM.
- As Sintered
- Vacuum Annealed
- Arc Cast
- Stress Relieved
- Cold Worked
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
powder-metallurgy blank, unworked | Pressed-and-sintered blank before forging/rolling; residual porosity means low strength and ductility — normally an intermediate product, occasionally sold for crucibles and furnace parts. | 350 | 450 | 4 | 170 HB | 27 % IACS |
fully recrystallized in vacuum | Choose when maximum dimensional stability and creep resistance above 1400 °C matter more than room-temperature strength; more brittle at RT because DBTT rises. | 420 | 560 | 25 | 12 HRC | 126 W/m·K |
vacuum arc cast and wrought-worked billet | Vacuum-arc-cast route giving very low interstitial content and coarse grain — preferred for large forged dies and high-temperature creep parts. | 560 | 700 | 18 | 20 HRC | 32 % IACS |
Stress RelievedDefaultThis page wrought, stress relieved below recrystallization | Standard stocked condition for rod, plate and forgings — best combination of room-temperature strength, ductility and dimensional stability up to ~1300 °C. | 760 | 900 | 15 | 26 HRC | 118 W/m·K |
as-swaged / as-rolled, unrecrystallized | Highest room-temperature strength and hardness (thin sheet, wire, small rod); limited ductility and residual stress, not for service above ~1000 °C. | 940 | 1,050 | 8 | 31 HRC | 29 % IACS |
What is TZM Stress Relieved?
TZM Stress Relieved is TZM heat treated to Stress Relieved — standard stocked condition for rod, plate and forgings — best combination of room-temperature strength, ductility and dimensional stability up to ~1300 °C. TZM Stress Relieved has a yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 88% of refractory metal grades. Elongation at break is 15% and the elastic modulus is 315 GPa (45.7 Msi). TZM Stress Relieved has a density of 10.22 g/cm³ (0.369 lb/in³), heavier than 68% of refractory metal grades. It melts at 2,617°C (4,743 °F).
Advantages
- Easy to machine — 45/100, better than 99% of refractory metal grades
- High strength — 760 MPa (110 ksi), better than 88% of refractory metal grades
- High electrical conductivity — 30 % IACS, better than 83% of refractory metal grades
- Conducts heat well — 118 W/m·K (68.2 BTU/hr·ft·°F), better than 81% of refractory metal grades
- Stiff — 315 GPa (45.7 Msi), better than 78% of refractory metal grades
Limitations
- Needs corrosion protection — 45/100, worse than 86% of refractory metal grades
- Difficult to weld — 20/100, worse than 79% of refractory metal grades
TZM Stress Relieved properties
Typical room-temperature values for TZM Stress Relieved; 11 are specific to this condition. Other listed values are TZM reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
TZM Stress Relieved has a density of 10.22 g/cm³ (0.369 lb/in³), heavier than 68% of refractory metal grades. It melts at 2,617°C (4,743 °F).
Mechanical16
TZM Stress Relieved has a yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 88% of refractory metal grades. Elongation at break is 15% and the elastic modulus is 315 GPa (45.7 Msi).
Thermal6
TZM Stress Relieved is rated for continuous service to 1,300°C (2,372 °F). It conducts heat at 118 W/m·K (68.2 BTU/hr·ft·°F), better than 81% of refractory metal grades. Thermal expansion is 5.3 µm/m·K (2.94 µin/in·°F).
Electrical3
TZM Stress Relieved conducts electricity at 30 % IACS, better than 83% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 86% of refractory metal grades.
Sustainability4
Producing a kilogram of TZM Stress Relieved takes about 380 MJ of energy and emits 26 kg of CO₂ — less than 78% of refractory metal grades. Typical recycled content is 25%.
Manufacturability7
TZM Stress Relieved's machinability is fair (45/100, better than 99% of refractory metal grades); weldability poor (20/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with TZM Stress Relieved
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 Stress Relieved — frequently asked
What is TZM Stress Relieved used for?
TZM Stress Relieved 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 Stress Relieved?
TZM Stress Relieved has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 88% of refractory metal grades. Strength varies by condition: see the 5 listed tempers.
Is TZM Stress Relieved easy to machine?
Reasonably — machinability is rated fair (45/100, better than 99% 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 Stress Relieved 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 Stress Relieved?
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 Stress Relieved 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 Stress Relieved?
TZM Stress Relieved is rated for continuous use to about 1,300°C (2,372 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
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.