Researchers achieve breakthrough in 3-D printed marine grade stainless steel (US)

LLNL materials scientist Joe McKeown looks on as postdoc researcher Thomas Voisin examines a sample of 3D printed stainless steel.; Researchers say the ability to 3D print marine grade, low-carbon stainless steel (316L) could have widespread implications for industries such as aerospace, automotive, and oil and gas.

“Marine grade” stainless steel is valued for its performance under corrosive environments and for its high ductility—the ability to bend without breaking under stress—making it a preferred choice for oil pipelines, welding, kitchen utensils, chemical equipment, medical implants, engine parts and nuclear waste storage. However, conventional techniques for strengthening this class of stainless steels typically comes at the expense of ductility. Lawrence Livermore National Laboratory (LLNL) researchers, along with collaborators at Ames National Laboratory, Georgia Tech University and Oregon State University, have achieved a breakthrough in 3-D printing one of the most common forms of marine grade stainless steel—a low-carbon type called 316L—that promises an unparalleled combination of high-strength and high-ductility properties for the ubiquitous alloy. The research appears online Oct. 30 in the journal Nature Materials .

“In order to make all the components you’re trying to print useful, you need to have this material property at least the same as those made by traditional metallurgy,” said LLNL materials scientist and lead author Morris Wang. “We were able to 3-D print real components in the lab with 316L stainless steel, and the material’s performance was actually better than those made with the traditional approach. That’s really a big jump. It makes additive manufacturing very attractive and fills a major gap.”

Wang said the methodology could open the floodgates to widespread 3-D printing of such stainless steel components, particularly in the aerospace, automotive and oil and gas industries, where strong and tough materials are needed to tolerate extreme force in harsh environments.

To successfully meet, and exceed, the necessary performance requirements for 316L stainless steel, researchers first had to overcome a major bottleneck limiting the potential for 3-D printing high-quality metals, the porosity caused during the laser melting (or fusion) of metal powders that can cause parts to degrade and fracture easily. Researchers addressed this through a density optimization process involving experiments and computer modeling, and by manipulating the materials’ underlying microstructure.

“This microstructure we developed breaks the traditional strength-ductility tradeoff barrier,” Wang said. “For steel, you want to make it stronger, but you lose ductility essentially; you can’t have both. But with 3-D printing, we’re able to move this boundary beyond the current tradeoff.”

Using two different laser powder bed fusion machines, researchers printed thin plates of stainless steel 316L for mechanical testing. The laser melting technique inherently resulted in hierarchical cell-like structures that could be tuned to alter the mechanical properties, researchers said.

“The key was doing all the characterization and looking at the properties we were getting,” said LLNL scientist Alex Hamza, who oversaw production of some additively manufactured components. “When you additively manufacture 316L it creates an interesting grain structure, sort of like a stained-glass window. The grains are not very small, but the cellular structures and other defects

LLNL postdoc researcher Thomas Voisin, a key contributor to the paper, has performed extensive characterizations of 3-D printed metals since joining the Lab in 2016. He believes the research could provide new insights on the structure-property relationship of additively manufactured materials.

“Deformation of metals is mainly controlled by how nanoscale defects move and interact in the microstructure,” Voisin said. “Interestingly, we found that this cellular structure acts such as a filter, allowing some defects to move freely and thus provide the necessary ductility while blocking some others to provide the strength. Observing these mechanisms and understanding their complexity now allows us to think of new ways to control the mechanical properties of these 3-D printed materials.”

Wang said the project benefitted from years of simulation, modeling and experimentation performed at the Lab in 3-D printing of metals to understand the link between microstructure and mechanical properties. He called stainless steel a “surrogate material” system that could be used for other types of metals.

The eventual goal, he said, is to use high-performance computing to validate and predict future performance of stainless steel, using models to control the underlying microstructure and discover how to make high-performance steels, including the corrosion-resistance. Researchers will then look at employing a similar strategy with other lighter weight alloys that are more brittle and prone to cracking.

The work took several years and required the contributions of the Ames Lab, which did X-ray diffraction to understand material performance; Georgia Tech, which performed modeling to understand how the material could have high strength and high ductility, and Oregon State, which performed characterization and composition analysis.

Source :

https://www.llnl.gov/news/lab-researchers-achieve-breakthrough-3d-printed-marine-grade-stainless-steel

THE FUTURE OF MATERIALS SUMMIT- November 13th – 14th 2017 | Luxembourg (US)

Innovations such as 3D printing, robotics, extreme customisation and high-performance computing are just some of the elements that will shape the future of manufacturing. But nothing will impact how things are made, and what they are capable of, more than the materials manufacturers use.

Advancements in material science are at a turning point. From programmable matter to smart polymers Continue reading

Boeing Invests in Gamma Alloys a supplier of reinforced aluminum alloys (US)

CHICAGO, Nov. 1, 2017 /PRNewswire/ — Boeing [NYSE: BA] announced its investment in Valencia, Calif.-based Gamma Alloys, a leader in aluminum alloys focused on developing advanced metal-matrix composites for use in aerospace, automotive and other industries. This investment by Boeing HorizonX Ventures, which was established earlier this year, is its first in advanced materials and machining development and applications. “The wear, strength, durability and machining characteristics of Gamma’s materials have the opportunity to further reduce the weight ofContinue reading

Greg Mulholland, the founder and CEO of the machine learning materials startup Citrine Informatics (US)

Greg Mulholland is the Chief Executive Officer and Co-Founder of Citrine Informatics, the data analytics platform for materials and chemicals. He works with partners along the materials value chain to use state of the art data science techniques to identify areas of improvement and optimization in advanced materials discovery, product design, and manufacturing. He has co-authored 20 peer-reviewed publications in materials science andContinue reading

High-Entropy Alloy-Coated Nanolattice Structures (US)

In this work microfabricated three-dimensional polymeric nanolattices were conformably coated with a thin layer of high-entropy alloy (CoCrFeNiAl0.3) film via physical vapor deposition.

Periodic three-dimensional (3D) structures with nanoscale constituents, often referred to as ‘‘nanolattices’’, are of extensive interest recently due to the rapid advances in additive manufacturing (such as 3D printing) at the micro/nano-scale. They have great potentials to be used for a variety of engineering applications, such as light-weight structural materials, functional frameworks for sustainable energy, scaffolds for cells culturing and drug Continue reading

New-York Governor Visits Norsk Titanium Plant (US)

Norsk Titanium is the only company that manufactures FAA-approved structural titanium components for the aerospace industry using a patented rapid plasma 3D printing technique.  Based in Norway, its global manufacturing facility is located in Plattsburgh.  On Tuesday, New York Governor Andrew Cuomo visited the plant and officiallydedicated the facility. New York State and SUNY Polytechnic invested $125 million to bring the company toContinue reading

Welding trials of new Aubert & Duval nickel alloy, AD730® (US)

Introduction

Aubert & Duval designed the new nickel alloy AD730® in response to the need for metals that can function at high temperatures in fields such as aerospace, energy, and the automotive industry.

The industrial environment

The need to enhance the efficiency of aero engines has been the driving force for the development of new materials that combine high tensile strength, resistance to fatigue and creep with the capability to operate in the 700°C/750°C (1292°F/1382°F) temperature range. In the same way, new power generation concepts, aiming at higher

Continue reading

ArcelorMittal R&D hopes ‘to be here another 50 years (US)

Originally part of the Purdue University Calumet campus in Hammond, Inland Steel moved its research and development facility to Cline Avenue and Columbus Drive in East Chicago, a few miles south of its steel mill in Indiana Harbor, 50 years ago. At the time, the steel company’s researchers didn’t have computers or even calculators. They did all the math by hand. Today about 200 scientists and researchers work on state-of-the-art technologies in 25 different laboratories in Skidmore, Owings & Merrill-designed buildings on a 49-acre dune- and swale-lined campus. It’s a key research facility that develops new grades of steel and ways to improveContinue reading

US Army Researchers Discover Aluminum Alloy That Reacts With Water To Create Hydrogen (US)

Researchers with the U.S. Army accidentally discovered a new way to produce hydrogen with aluminum. The new aluminum nanomaterial produces hydrogen when exposed to water.  (David McNally | U.S. Army )

Car manufacturers have turned to hydrogen as one of the go-to sources of fuel for clean energy in vehicles, but despite its abundant nature, the gas is difficult to store and transport. However, an accidental discovery may just have found the solution to the hydrogen problem that could potentially turn things around for the industry. A team of U.S. Army researchers hard at work during a routine materials testing at the Aberdeen Proving GroundContinue reading

Researchers Evaluate Aluminum Alloy Using Neutron (US)

Neutrons peered inside an aluminum-cerium engine component to see how it reacted to high heat and stress

In a first-of-its-kind experiment, researchers at Oak Ridge National Laboratory used neutrons to investigate the performance of components made of a new aluminum-cerium alloy on a gasoline-powered engine while it was running. They wanted to determine if the alloy would hold up under the heat and stress of an internal combustion Continue reading