A D V A N C E D M A T E R I A L S & P R O C E S S E S | A P R I L 2 0 2 2 8 METALS | POLYMERS | CERAMICS IMPROVING PROTECTIVE GEAR A versatile foam-like material was created by researchers from Johns Hopkins University, Baltimore, with applications in the development of protective gear and parts for the auto and aerospace industries. The new shock-absorbing material protects like a metal, but is lighter, stronger, and reusable. The research team was able to add strength while reducing weight with high energy-absorbing liquid crystal elastomers, which have mainly been used in actuators and robotics. During experiments to test the material’s ability to withstand impact, it held up against strikes from objects weighing about four to 15 pounds, coming at speeds of up to 22 mph. The tests were restrained to this speed due to limits of the testing machines, but the team is confident the padding could safely absorb even greater impacts. The team is exploring a collaboration with a helmet company to design, fabricate, and test next-generation helmets for athletes and the military. www.jhu.edu. The sti ness of the high-entropy Elinvar alloy remains invariant with temperature. Courtesy of City University of Hong Kong. SUPERELASTIC ALLOY A research team led by the City University of Hong Kong discovered a first-of-its-kind superelastic alloy that can retain its stiffness after being heated to 1000 K (~726.85°C) or above with nearly zero energy dissipation. The high-entropy alloy reveals the Elinvar effect, where the alloy firmly retains its elastic modulus over a very wide range of temperature changes. The team believes that the alloy can be applied in manufacturing high-precision devices for space missions. The mechanism behind the discovery is a special highly distorted lattice structure with a complex atomic-scale chemical composition. Because of the combination of unique structural features, the high-entropy Elinvar alloy has a very high energy barrier against dislocation movements. Consequently, The private equity firm Core Industrial Partners, Chicago, announces the acquisition of Haven Manufacturing by CGI Automated Manufacturing, also owned by Core. Haven specializes in components for medical devices and equipment, offering design assistance, prototyping, EDM, waterjet, laser etching, blasting, grinding and passivation, and CNC machining. havenmanufacturing.com. BRIEF it displays an impressive elastic strain limit and a nearly 100% energy storage capacity. The team also discovered that the alloy has an elastic limit of about 2% in bulk forms at room temperature, in sharp contrast to conventional crystalline alloys which have an elastic limit of less than 1%. The team developed three atomic structural models for the same alloy with different distributions of the element atoms and compared the properties. They patented the discovery based on this systematic investigation. Researchers say the alloy could be used for energy storage for subsequent energy conversion, since its elasticity doesn’t dissipate energy. The team envisions many applications for the alloy, particularly in aerospace engineering, in which devices and machinery are expected to undergo drastic temperature changes. www.cityu.edu.hk. Researchers studied the energy-absorbing capability of liquid crystal elastomers. Courtesy of Johns Hopkins University.
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