A group of scientists from the National Institute of Standards and Technology,
the University of Wisconsin-Madison and the Argonne National Laboratory have pinpointed specific 17-4 steel compositions that,
when printed, have properties identical to those of the conventionally produced version.
The researchers used high-energy X-rays from a particle accelerator to obtain high-speed data about the printing process,
which they used to develop their strategy, which was published in the journal Additive Manufacturing.
Strength and durability are crucial for nuclear power plants, airliners, cargo ships, and other critical technologies.
For this reason, many are made of the remarkably durable alloy 17-4 precipitation hardening (PH) stainless steel.
For the first time, 17-4 PH steel can now be reliably 3D printed while maintaining its beneficial properties.
The methodology used to examine the material in this study may also lay the groundwork for a better comprehension of how to print other types of materials and predict their properties and performance.
Although 3D printing has advantages over traditional manufacturing, some materials can produce results that are too erratic for some applications.
Due to the process’ rapid temperature changes, printing metal is particularly difficult.
Optimising additive manufacturing
The goal of the new study’s authors was to shed light on what transpires during rapid temperature changes
and identify a strategy for accelerating the internal structure’s transition to martensite.
Just as a high-speed camera is required to capture a hummingbird’s flapping wings,
specialized equipment was required by the researchers to capture rapid structural changes that take place in milliseconds. They discovered synchrotron X-ray diffraction, or XRD, to be the ideal tool for the job.
According to Lianyi Chen, PhD, professor of mechanical engineering at UW-Madison and study co-author, “in XRD, X-rays interact with a material and will form a signal that is like a fingerprint corresponding to the material’s specific crystal structure.”
Mechanical testing revealed that the 3D-printed steel had the same strength as conventionally produced steel due to its martensite structure and strength-inducing nanoparticles.
A new frontier
The recent study might be influential beyond 17-4 PH steel as well.
The information obtained from the XRD-based method could be used to develop and test computer models intended to forecast the quality of printed parts in addition to optimizing other alloys for 3D printing.
“The barrier to commercial use is lowered by our 17-4’s dependability and reproducibility.
Manufacturers should be able to print 17-4 structures that are just as good as traditionally manufactured parts if they adhere to this composition, according to Chen.
Source: Journal Additive Manufacturing