What’s the difference between single-crystal and equiaxed casting for fuel modules?

Microstructure and Grain Orientation

In single crystal casting, the alloy solidifies as one continuous grain, eliminating grain boundaries that typically serve as weak points under thermal and mechanical stress. This provides superior creep resistance and durability for high-pressure fuel system zones. In contrast, equiaxed crystal casting produces multiple grains with random orientation, providing good strength but lower performance under extreme heat.

Performance Under High Temperature and Stress

Single-crystal alloys such as PWA 1484 and TMS-75 excel in extreme temperature applications, offering excellent creep resistance for fuel injector housings and turbine interface modules. Equiaxed casting is still effective for moderate temperature zones but may require additional reinforcement for fatigue resistance.

Manufacturing Complexity and Cost

Single-crystal casting demands strict directional solidification control, resulting in higher cost and longer production time. It is best suited for critical aerospace fuel system components requiring extended lifecycle. Equiaxed casting offers broader material flexibility and shorter lead times, making it suitable for complex geometries and non-critical aerospace fuel modules that still require strong mechanical integrity.

Post-Processing and Performance Enhancement

Regardless of casting method, components must undergo hot isostatic pressing (HIP) and material testing and analysis to ensure reliability. Final shaping via precision superalloy CNC machining guarantees fitment with fuel channels and sealing surfaces in aerospace and power generation systems.