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I saw this & thought it might be of interest to my fellow forumites.
Link: http://www.sciencemag.org/news/2017/10/3d-printing-doubles-strength-stainless-steel
The first 3 paragraphs are filler. The last 3: "
The problem has been that, on a microscopic level, printed stainless steels are usually highly porous, making them weak and prone to fracture. “The performance has been awful,” says Yinmin “Morris” Wang, a materials scientist at Lawrence Livermore National Laboratory in California. Several years ago, Wang and his colleagues came up with an approach for using lasers and a rapid cooling process to fuse metal alloy particles together in a dense, tightly packed structure.
Now, they’ve extended that work by designing a computer-controlled process to not only create dense stainless steel layers, but to more tightly control the structure of their material from the nanoscale to micron scale. That allows the printer to build in tiny cell wall–like structures on each scale that prevent fractures and other common problems. Tests showed that under certain conditions the final 3D printed stainless steels were up to three times stronger than steels made by conventional techniques and yet still ductile, the scientists report today in Nature Materials.
“What they have done is really exciting,” says Rahul Panat, a mechanical engineer at Carnegie Mellon University in Pittsburgh, Pennsylvania. What’s more, Panat says, is that Wang and his colleagues used a commercially available 3D printer and laser to do the work. That makes it likely that other groups will be able to quickly follow their lead to make a wide array of high-strength stainless steel parts for everything from fuel tanks in airplanes to pressure tubes in nuclear power plants. And that, in turn, will likely only increase the growing fervor over 3D printing."
The link in the text leads to a nature.com article behind a paywall:
"Additively manufactured hierarchical stainless steels with high strength and ductility"
Link: https://www.nature.com/articles/nmat5021
Abstract: "Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength–ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications."
Link: http://www.sciencemag.org/news/2017/10/3d-printing-doubles-strength-stainless-steel
The first 3 paragraphs are filler. The last 3: "
The problem has been that, on a microscopic level, printed stainless steels are usually highly porous, making them weak and prone to fracture. “The performance has been awful,” says Yinmin “Morris” Wang, a materials scientist at Lawrence Livermore National Laboratory in California. Several years ago, Wang and his colleagues came up with an approach for using lasers and a rapid cooling process to fuse metal alloy particles together in a dense, tightly packed structure.
Now, they’ve extended that work by designing a computer-controlled process to not only create dense stainless steel layers, but to more tightly control the structure of their material from the nanoscale to micron scale. That allows the printer to build in tiny cell wall–like structures on each scale that prevent fractures and other common problems. Tests showed that under certain conditions the final 3D printed stainless steels were up to three times stronger than steels made by conventional techniques and yet still ductile, the scientists report today in Nature Materials.
“What they have done is really exciting,” says Rahul Panat, a mechanical engineer at Carnegie Mellon University in Pittsburgh, Pennsylvania. What’s more, Panat says, is that Wang and his colleagues used a commercially available 3D printer and laser to do the work. That makes it likely that other groups will be able to quickly follow their lead to make a wide array of high-strength stainless steel parts for everything from fuel tanks in airplanes to pressure tubes in nuclear power plants. And that, in turn, will likely only increase the growing fervor over 3D printing."
The link in the text leads to a nature.com article behind a paywall:
"Additively manufactured hierarchical stainless steels with high strength and ductility"
Link: https://www.nature.com/articles/nmat5021
Abstract: "Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength–ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications."
