Page 14 - 3D Metal Printing Fall 2017

3D MATERIALS
Nanoparticles Advance 3D Printing
by Making the Unweldable Manageable
A technique for 3D printing parts made of unweldable aluminum alloys, including Al7075 and Al6061, appears to have solved an ages-old challenge associated with such materials—hot crack- ing, a condition that renders a metal part to be pulled apart like a flaky biscuit during the additive
manufacturing (AM) process when the thin layers of alloy powders are heated with a laser or some other direct heat source.
A team of engineers at HRL Laboratories, Malibu, CA, addressed this challenge using a nanoparticle functionalization technique, which solves the problem by decorating the alloy powders with specially
selected nanoparticles. The nanoparticle-functionalized powder feeds into a 3D printer, which lay- ers the powder. During melting and solidification, analogous to welding, the nanoparticles act as nucleation sites for the desired alloy microstructure, preventing hot cracking and allowing for retention of full alloy strength in the manufactured part. This AM technique is scalable and also can be applied to high-strength steels and nickel-based superalloys.
"We're using a 70-yr.-old nucleation theory to solve a 100-yr.-old problem with a 21st-century machine," says Hunter Martin, who co-led the team with Brennan Yahata. Both are engineers in HRL's Sensors and Materials Laboratory, and Ph.D. candidates at the University of California, Santa Barbara (UCSB). Together with UCSB Professor Tresa Pollock and HRL engineers Jacob Hundley, Justin Mayer and Tobias A. Schaedler, they co-authored the paper, “3D printing of high- strength aluminum alloys,” published in the September 21, 2017, issue of Nature.
To find the correct nanoparticles—in this case zirconium-based nanoparticles—the HRL team enlisted Citrine Informatics software to sort through the myriad possible particles to find the one with the right properties. “The point of using the software was to do a selective approach to the nucleation theory we knew to find the materials with the exact properties we needed,” says Yaha- ta. “This big-data analysis narrowed the field of available materials from hundreds of thousands to a select few. We went from a haystack to a handful of possible needles."
HRL Laboratories: www.hrl.com
Stainless Steel Expands Metal 3D-Printing Repertoire at Materialise
Materialise NV, headquartered in Leuven, Belgium, has introduced 316L and 1.4404 stainless steel into its metal 3D-printing portfolio. The additions join a menu of more than 30 materials, including titanium and aluminum, at one of Europe’s largest factories for 3D printing. This announcement follows the 2016 opening of Materialise’s new metal 3D-printing factory in Bre- men, Germany. By expanding its material portfolio, Materialise aims to better serve its industrial customers in the sectors of manufacturing, automotive and aeronautics.
Through the introduction of 316L, a low-carbon high-strength stainless alloy with corrosion- resistant properties, the company plans to capitalize on applications in machine-building and toolmaking. In addition, the material is widely used for food-safe applications and medical instru- ments, and is well-suited to the production of durable prototypes, spare parts and ductwork. Materialise: www.materialise.com
OR Laser and Heraeus Partner to Develop
AM Materials
OR Laser has entered into an agreement with materials developer Her- aeus to develop optimized metal-powdered materials for AM applications using OR Laser’s Orlas Creator platform. As part of the agreement, Heraeus will obtain an Orlas Creator sys- tem, which the company will test with a range of its pow- dered materials. Heraeus then will seek to develop specific 3D-printing param- eters and guidelines for its powders.
OR Laser: www.or-laser.com/en Heraeus: www.heraeus.com/en
ATI, GE Aviation Announce Meltless-Titanium Joint Venture
Allegheny Technologies Inc. (ATI), Pittsburgh, PA, announced a joint venture with GE Aviation on develop- ment of a new meltless-titani- um-alloy powder-manufactur- ing technology and construction of an R&D pilot production facility.
ATI will provide opera- tional, technical and project support to the joint venture, which also will draw upon GE Aviation’s engineering and development capabilities and technical knowledge of the use of alloyed titanium powders.
“We are pleased to join
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