Hot sections. Superalloys. Up to 1500°C+.

Continuous service temperature ranges. Above these, materials degrade rapidly or fail.

Nickel superalloys dominate high-temperature structural applications from 600-1000°C.

Generally: materials lose 10-30% strength for every 100°C above room temperature. Specifically: 6061 aluminum loses 50% strength by 200°C. Mild steel loses 30% by 400°C. 304 stainless loses 30% by 600°C. Inconel 718 loses 20% by 650°C (its designed service temp). For design, use temperature-derated material data, not room-temperature values.

Creep becomes dominant design consideration above ~30% of melting temperature (absolute scale, K). For room-temperature materials: aluminum above 100-150°C, mild steel above 400°C, stainless above 500°C, Inconel above 600°C. For applications with sustained load at elevated temperature, creep is the primary design criterion. Short-term or intermittent exposure: creep less critical.

Molybdenum oxide (MoO3) is volatile — sublimes away above 500°C in oxidizing atmosphere. Instead of forming protective layer, MoO3 evaporates, exposing fresh Mo metal which oxidizes further. Catastrophic mass loss. In vacuum or inert atmosphere, Mo is stable to 1800°C+. For Mo service in air above 500°C, silicide or aluminide coatings required. Same issue for tungsten and some other refractory metals.

Yes, but limits. Standard thermoplastics: up to 100°C continuous. Engineering plastics (PEEK, Ultem, PPS): 150-260°C. Polyimides (Vespel, Meldin): up to 300°C. Above 300°C, plastics generally not viable — use metals or ceramics. For specific high-temperature polymer applications, consult specific material data sheets — temperature ratings vary with load and time.

Specify: (1) Continuous service temperature, (2) Peak temperature (short-term excursion), (3) Atmosphere (air, vacuum, inert, reducing), (4) Loading (static, cyclic, pressure), (5) Expected service life, (6) Thermal cycling frequency. These together determine material. Never over-specify — high-temperature alloys are expensive ($50-150/kg vs $2-8/kg for steel).

High-temperature alloys often require specific heat treatment for optimal properties. Inconel 718: solution treat at 980°C + age at 720°C + age at 620°C to achieve full precipitation hardening. Without heat treatment, properties significantly lower. We coordinate heat treatment with NADCAP-qualified heat treat partners for aerospace parts.