Amazing stuff! Humans transcending nature!
"... Most common alloys, like stainless steel or bronze, are made with one primary metal mixed with smaller amounts of other elements. But an emerging class of materials known as high entropy alloys (HEAs) involves mixing five different elements together in roughly equal proportions. The resulting alloys end up with intriguing and useful properties, like high strength-to-weight ratios and stiffness that rises with the temperature. ...
The new study focuses on a HEA containing aluminum, cobalt, chromium, iron and nickel in equal measures. This particular mix has been experimented with for a few years now, but the team made it using a technique that hadn’t been applied to it yet – laser powder bed fusion. Essentially, powdered forms of the original metals are laid out on a surface, then blasted with a high-powered laser that causes them to rapidly melt and resolidify.
This technique, a form of 3D printing, gives the final alloy a very different microstructure than it gets from other manufacturing methods. ...
net, with alternating layers of different cubic crystalline structures. This gives the HEA a yield strength of around 1.3 Gigapascals, almost three times stronger than when it’s made using conventional casting methods. At the same time, it’s also more ductile, countering a common trade-off. ..."
net, with alternating layers of different cubic crystalline structures. This gives the HEA a yield strength of around 1.3 Gigapascals, almost three times stronger than when it’s made using conventional casting methods. At the same time, it’s also more ductile, countering a common trade-off. ..."
From the abstract:
"Additive manufacturing produces net-shaped components layer by layer for engineering applications. The additive manufacture of metal alloys by laser powder bed fusion (L-PBF) involves large temperature gradients and rapid cooling, which enables microstructural refinement at the nanoscale to achieve high strength. However, high-strength nanostructured alloys produced by laser additive manufacturing often have limited ductility. Here we use L-PBF to print dual-phase nanolamellar high-entropy alloys (HEAs) of AlCoCrFeNi2.1 that exhibit a combination of a high yield strength of about 1.3 gigapascals and a large uniform elongation of about 14 per cent, which surpasses those of other state-of-the-art additively manufactured metal alloys. .... The large tensile ductility arises owing to the high work-hardening capability of the as-printed hierarchical microstructures in the form of dual-phase nanolamellae embedded in microscale eutectic colonies, which have nearly random orientations to promote isotropic mechanical properties. The mechanistic insights into the deformation behaviour of additively manufactured HEAs have broad implications for the development of hierarchical, dual- and multi-phase, nanostructured alloys with exceptional mechanical properties."
No comments:
Post a Comment