The nickel superalloys worth printing are the ones that crack

High gamma-prime content gives high-temperature strength and makes the alloy crack during solidification. That tension defines the field.

By LasersNews Desk·14 Jul 2026·2 min read

A close-up of an illuminated 3D printer in action, highlighting modern technology. — Photo by Jakub Zerdzicki on Pexels

Nickel superalloys are the reason turbine engines work at the temperatures they do, and their high-temperature strength comes largely from the gamma-prime precipitate phase. The alloys with the most gamma-prime are the strongest at temperature and the most difficult to weld or print.

The mechanism

Two related cracking behaviours affect these alloys.

Solidification cracking occurs in the mushy zone during freezing, where thermal contraction pulls apart a partly solid structure that liquid cannot feed.

Strain age cracking occurs during post-build heat treatment. The gamma-prime phase precipitates rapidly, the material hardens while residual stress is still present, and it cracks rather than relaxing.

Additive processing makes both worse than casting does, because thermal gradients and cooling rates are far higher and the stress state is more severe.

The printable and the difficult

Alloys with modest gamma-prime — IN718, IN625, Haynes grades — print reliably and have established parameter sets and property databases. They are the workhorses of additive superalloy production.

Alloys with high gamma-prime — CM247LC, René 108, similar — are the ones with the temperature capability that makes turbine hot sections possible, and they crack under standard processing.

That is the tension: the alloys people most want to print are the ones the process handles worst.

What is being done

Parameter development. Reduced thermal gradients through plate heating, modified scan strategies and slower cooling narrow the cracking window somewhat.

Alloy modification. Adjusting composition to reduce cracking susceptibility while retaining most of the temperature capability, which parallels what happened with aluminium.

Post-processing. HIP closes some cracks, though as with porosity it works better on some crack types than others.

Hybrid approaches. Building a printable alloy substrate and depositing a high-performance alloy where the temperature demands it.

Where it stands

Additive production of the most demanding hot-section components remains limited, and cast and directionally solidified components hold those applications. Additive has established itself firmly in the surrounding structures, in repair, and in components using the more printable alloys.

That is a real position rather than a disappointment, and the direction of alloy development suggests the boundary will keep moving — slowly, because each new alloy carries a qualification burden as large as the metallurgy.

This article was produced by the LasersNews AI desk and reviewed by our editors.