Mastering Extreme Heat: Key High-Temperature Alloys for Additive Manufacturing

Understanding their properties and capabilities is essential for pushing the boundaries of high-performance components.

1. GH4099: High-Strength Ni-Cr Solution & Precipitation Hardened Alloy

Use: Long-term service ≤ 900°C, short-term ≤ 1000°C (combustion chambers, afterburners).

Key: Combines Cr, Co, W, Mo (solution) with Al, Ti (γ' precipitation) plus B, Ce, Mg (grain boundary). Excellent strength, stability, workability, weldability.

Forms: Hot-rolled bars, plates, wires, forgings. Used directly after solution treatment.

2. GH4169 (Inconel 718-type): Versatile Ni-Cr-Fe Precipitation Hardened Alloy

Use: -253°C to 650°C long-term, ≤ 800°C short-term (turbine disks, rings, blades, casings).

Key: High strength ≤ 650°C, excellent fatigue, oxidation, corrosion resistance, weldability, stability. Available in standard, high-strength (HS), and direct-aged (DA) variants (HS & DA for critical rotating parts).

Forms:Bars (hot/cold), plate, sheet, wire, tube, rings, forgings.

3. K438/IN738: Premium Ni-Base Cast Superalloy for Hot Corrosion

Use: ≤ 900°C (turbine blades/vanes).

Key:Exceptional hot corrosion resistance, moderate strength, good stability (high Cr, Ta, Nb). Microstructure control (grain size/columnar zones) is vital for thermal fatigue resistance. Widely used in marine/industrial turbines and aero-engines.

Forms:Investment cast blades & vanes.

4. M247 (MAR-M247): High γ' Nickel-Base Casting Legend

Use: Long-term ≥ 980°C (turbine blades, nozzles).

Key:High γ' volume (>60%) delivers outstanding creep strength. Excellent castability (Hf addition) for equiaxed (EQ), directionally solidified (DS), or single-crystal (SX) forms. Good oxidation resistance. Derivative CM247LC offers optimized carbides for modern DS/SX applications.

Status:Remains a cornerstone high-temperature casting alloy.

5. GH3230 (Haynes 230-type): Robust Ni-Cr Solid Solution Alloy

Use: 700°C - 1050°C (combustion chambers).

Key: High strength, thermal fatigue resistance, excellent oxidation/hot corrosion resistance. W, Mo provide solid solution strengthening; Cr ensures oxidation resistance. Stable (no TCP after 800°C/1000h).

Forms: Cold-rolled sheet/strip.

6. GH5188 (Haynes 188-type): Oxidation-Resistant Co-Ni-Cr Alloy

Use:≤ 1100°C oxidation / ≤ 980°C strength (combustors, guide vanes).

Key: W (14%) provides strength; Cr + La (0.03-0.12%) ensures superb oxidation resistance. Good workability and weldability. Avoid carbon/copper contamination.

Forms: Sheet (cold/hot), plate, bar, forgings, wire. Superior corrosion resistance vs. GH3536.

7. GH3536 (Hastelloy X-type): Reliable Ni-Cr-Fe Solid Solution Alloy

Use: Long-term ≤ 900°C, short-term ≤ 1080°C (combustors, hot sections).

Key: Moderate creep strength, excellent oxidation/corrosion resistance, good fabricability/weldability. Widely used in aero-engines (combustors, diffusers) and industry.

Forms:Wrought product equivalents to cast alloy K4536.

Choosing the Right Alloy for AM Success

Selecting the optimal high-temperature alloy for your AM project depends critically on the application's maximum temperature, environmental conditions (oxidation, corrosion), required mechanical properties (strength, creep, fatigue), and post-processing needs. These alloys – GH4099, GH4169, K438, M247, GH3230, GH5188, and GH3536 – represent the core toolkit for pushing AM into the most extreme environments. Leverage their unique strengths to build the next generation of high-performance components.