3D Printing Single Nickel Crystals with Flat Top Lasers

By on July 15th, 2022 in news, research

Tags: , , , ,

Researchers have developed a method of 3D printing single crystal nickel structures.

Crystallinity is a key goal of metal additive manufacturing systems: if the microstructures formed within the hot meltpool are aligned, the part will be much stronger. One way to do this is to encourage the formation of a crystal as the metal cools.

It’s easy to describe a crystal, but much harder to actually make one with a laser system.

There apparently have been research projects that have accomplished this feat, but the results have had limited size and are tricky to do. Often these experiments require a crystal “seed” from which the main crystal grows.

The new research is able to produce relatively large nickel crystals without using a seed at all. They explain:

“The exploration of flat-top laser profile in fabricating a single crystal (SX) structure using selective laser melting (SLM) in pure Ni was investigated. Optimization of the parameters led to the formation of a planar melt pool. A homogeneous near-{001}<100> texture with suppressed high-angle grain boundary (HAGB) in high building heights of >20 mm was achieved without an SX seed. In addition, the planar melt pool suppressed the geometrically necessary dislocation accumulation and prevented strain-induced continuous dynamic recrystallization that could cause HAGB formation. Thus, an SX structure with homogeneous near-{001}<100> texture and suppressed HAGB was successfully achieved without an SX seed.”

But what is a flat top laser, anyway? It’s a different form of laser. The normal laser type in use is Gaussian, which has a curved peak of energy composing the laser dot, while a flat top has a different profile that produces equal energy throughout the laser dot. This image illustrates the difference:

[Source: Edmund Optics]

This research could prove incredibly important for metal additive manufacturing, where considerable effort is spent each day by metallurgists and engineers try to tweak out the best possible print outcomes — meaning the best microstructures.

The ability to more easily create crystalline structures when printing will be attractive. It could be that metal 3D printer manufacturers might take a good look at flat top lasers, if this new process is able to scale.

Via Science Direct

By Kerry Stevenson

Kerry Stevenson, aka "General Fabb" has written over 8,000 stories on 3D printing at Fabbaloo since he launched the venture in 2007, with an intention to promote and grow the incredible technology of 3D printing across the world. So far, it seems to be working!

Leave a comment