July/August_AMP_Digital

6 FEEDBACK A team of researchers led by the University of Michigan is looking to de- velop a metamaterial that changes properties based on how an object comes into contact with it. The five- year, $7.5 million grant from the Of- fice of Naval Research, is a part of the Department of Defense’s 2020 Multi- HISTORICAL PERSPECTIVES STILL RELEVANT I read through nearly the entire issue of the May/June AM&P and just had to write you about how fantastic it is. The great article about a century of Wilson hardness testers by Matthias Pascher (“Hardness Testing Retrospec- tive: A Century of Wilson”) featured ex- cellent historical coverage and the ar- ticle on testing automotive aluminum (“Taking the Guesswork out of Auto- motive Aluminum Testing”) was inter- esting. The Michels and Michels article about the health benefits of copper in combating the coronavirus (“Can RESEARCH TRACKS We welcome all comments and suggestions. Send letters to joanne.miller@asminternational.org . disciplinary University Research Initia- tive program. Physicist Xiaoming Mao received the grant to bring her theoretical work of turning a metamaterial whose phys- ical properties are changeable from the nanoscale to the macroscale. Metama- terials are a type of material that get their properties from the way the mate- rial is structured rather than the materi- al itself. This means that, using the right method, the material can be construct- ed to have specific properties. In this case, when an object comes in contact with the edge of this meta- material, it changes the geometry of the material’s structure and quickly trans- forms its ability to carry stress and re- spond to forces. This allows a piece of solid material to absorb shock, direct stress, and help prevent damage. “For cars, you can easily imagine that if you change the material’s surface between the stiffness of a metal and the METAMATERIAL CHANGES PROPERTIES ON IMPACT softness of rubber, that could be very useful in collision protection,” says Mao, associate professor of physics. “These materials may have applications in de- fense, where it could be used to design helmets and armor.” The research team will use the grant to verify their method, original- ly published in a 2017 study in Nature Communications, in two ways: by us- ing 3D printing and by using self-assem- bling building blocks. Team member Ellen Arruda at the U-M College of Engineering, will use her expertise in 3D printing to print the ma- terial at the macroscale. Nicholas Kotov of U-M and Qian Chen of the University of Illinois will use their expertise in de- signing building blocks that can self-as- semble into any structure, which will create the material at the nanoscale. Other researchers include U-M physicist Kai Sun and engineer Zi Chen of Dart- mouth College. www.umich.edu . Copper Help Fight COVID-19?”) was ex- tremely interesting, and not surpris- ing to me as copper has been known to fight health problems from various germs for thousands of years! The nano- technology article also discussed sim- ilar problems in dealing with bacteria and was full of great information. I was so impressed by the qual- ity of this issue that I felt that I had to write to you and ex- press my pleasure in reading it. George Vander Voort, FASM ERRATA The May/June issue included duplicate figures in the article, “Im- proved Matrix Material for Diamond Cutter Bits” by Jonathan W. Bitler and Samuel Lomasney. Correct Figs. 6a and b are included below and also on- line in the revised digital edition avail- able at asminternational.org . A 3D printed specimen of topological mechanical metamaterials. Courtesy of Ellen Arruda, Xiaoming Mao, University of Michigan. 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 | J U L Y / A U G U S T 2 0 2 0 EBSD of samples after subsequent heat treatment: (a) Kennametal’s TMS formula (blend 1) after thermal cycling; and (b) conventionally carburized formula (blend 2) after thermal cycling. Gray phases represent a lattice structure that could not be indexed. (a) (b)